Android项目——智能农业

总结一下这一周关于智能农业APP项目的学习。

一、布局

APP最重要的就是与用户的交互界面，布局很重要。在智能农业APP这个项目中，布局十分简单，用户不需要花费多少时间便能熟练使用。

1、APP界面：

2、重点、难点部分布局

在布局中，没有什么难度，只有在智能农业界面中把方形的图片设置成圆形时需要注意一下。
首先在gradle中添加依赖：

    compile 'com.makeramen:roundedimageview:2.2.1'

然后布局中代码如下所示：

  <com.makeramen.roundedimageview.RoundedImageView
            app:riv_oval="true"
            android:id="@+id/light_img"
            android:layout_width="120dp"
            android:layout_height="120dp"
            android:src="@mipmap/guangzhao" />

如果没有app:riv_oval="true"这句话，那么图片还是不会变成圆形的。

二、Java代码

1、添加依赖

由于需要gson解析、使用OKHttp快速访问网络，所以需要添加两个依赖：

  compile 'com.google.code.gson:gson:2.8.2'

    compile 'com.squareup.okhttp3:okhttp:3.10.0'

2、从首页进入后的三个界面——智能农业界面、设置界面、帮助界面

• 创建三个fragment——HomePagerFragment、SettingFragment、HelpFragment。
  在HomePagerFragment中把首页布局文件写好：

<TextView
        android:id="@+id/home_page_top_lin"
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:gravity="center_horizontal"
        android:text="智能农业"
        android:textColor="#24bd3b"
        android:textSize="30dp" />
    <View
        android:layout_width="match_parent"
        android:layout_height="2dp"
        android:layout_below="@+id/home_page_top_lin"
        android:background="#b5b5b5"
        />

    <ScrollView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
         android:layout_alignParentLeft="true"
        android:layout_below="@+id/home_page_top_lin"
        android:overScrollMode="never"
        android:scrollbars="none"
        android:layout_marginTop="5dp">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical">

            <android.support.v4.view.ViewPager
                android:id="@+id/home_page_vp"
                android:layout_width="match_parent"
                android:layout_height="150dp"
                android:background="@mipmap/bana1">
            </android.support.v4.view.ViewPager>
    <LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    <View
        android:layout_width="match_parent"
        android:layout_height="1dp"
        android:background="#716c6c"/>

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="5dp"
        >

        <com.makeramen.roundedimageview.RoundedImageView
            app:riv_oval="true"
            android:id="@+id/co2_img"
            android:layout_width="120dp"
            android:layout_height="120dp"
            android:src="@mipmap/co2" />

        <TextView
            android:layout_toLeftOf="@+id/co2_warn_img"
            android:id="@+id/co2_concentation_tv"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_alignTop="@+id/co2_img"
            android:layout_margin="5dp"
            android:layout_toRightOf="@+id/co2_img"
            android:text="CO2浓度"
            android:textColor="#100909"
            android:textSize="25sp" />

        <RelativeLayout
            android:layout_toLeftOf="@+id/co2_right_img"
            android:id="@+id/co2_relative"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_below="@+id/co2_concentation_tv"
            android:layout_margin="5dp"
            android:layout_toRightOf="@+id/co2_img">

            <TextView
                android:id="@+id/co2_co2_tv"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:gravity="center_vertical"
                android:text="CO2:"
                android:textColor="#100909"
                android:textSize="25sp" />

            <TextView
                android:id="@+id/co2_values_tv"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginLeft="15dp"
                android:layout_toRightOf="@+id/co2_co2_tv"
                android:gravity="center_vertical"
                android:text="200"
                android:textColor="#e80c0c"
                android:textSize="25sp" />

        </RelativeLayout>

        <RelativeLayout
            android:layout_toLeftOf="@+id/co2_right_img"
            android:layout_alignBottom="@+id/co2_img"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_below="@+id/co2_relative"
            android:layout_margin="5dp"
            android:layout_toRightOf="@+id/co2_img">

            <TextView
                android:id="@+id/co2_set_tv"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:gravity="center_vertical"
                android:text="设定值:"
                android:textColor="#1fa433"
                android:textSize="15sp" />

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginLeft="15dp"
                android:layout_toRightOf="@+id/co2_set_tv"
                android:gravity="center_vertical"
                android:text="200"
                android:textColor="#605858"
                android:textSize="15sp" />

        </RelativeLayout>

        <ImageView
            android:id="@+id/co2_right_img"
            android:layout_width="20dp"
            android:src="@mipmap/right"
            android:layout_centerVertical="true"
            android:layout_alignParentRight="true"
            android:layout_height="60dp" />

        <ImageView
            android:id="@+id/co2_warn_img"
            android:layout_alignParentRight="true"
            android:layout_alignParentTop="true"
            android:src="@mipmap/p2"
            android:layout_width="50dp"
            android:layout_height="20dp" />

    </RelativeLayout>

    <View
        android:layout_width="match_parent"
        android:layout_height="1dp"
        android:background="#716c6c"/>
</LinearLayout>

            <LinearLayout  
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical"
   >
    <View
        android:layout_width="match_parent"
        android:layout_height="1dp"
        android:background="#716c6c"/>

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="5dp"
        >

        <com.makeramen.roundedimageview.RoundedImageView
            app:riv_oval="true"
            android:id="@+id/light_img"
            android:layout_width="120dp"
            android:layout_height="120dp"
            android:src="@mipmap/guangzhao" />

        <TextView
            android:id="@+id/light_intension_tv"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_alignTop="@+id/light_img"
            android:layout_margin="5dp"
            android:layout_toLeftOf="@+id/light_warn_img"
            android:layout_toRightOf="@+id/light_img"
            android:text="光照强度"
            android:textColor="#100909"
            android:textSize="25sp" />

        <RelativeLayout
            android:id="@+id/light_relative"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_below="@+id/light_intension_tv"
            android:layout_margin="5dp"
            android:layout_toLeftOf="@+id/light_right_img"
            android:layout_toRightOf="@+id/light_img">

            <TextView
                android:id="@+id/light_light_tv"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:gravity="center_vertical"
                android:text="光照"
                android:textColor="#100909"
                android:textSize="25sp" />

            <TextView
                android:id="@+id/light_values_tv"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginLeft="15dp"
                android:layout_toRightOf="@+id/light_light_tv"
                android:gravity="center_vertical"
                android:text="200"
                android:textColor="#e80c0c"
                android:textSize="25sp" />

        </RelativeLayout>

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_alignBottom="@+id/light_img"
            android:layout_below="@+id/light_relative"
            android:layout_margin="5dp"
            android:layout_toLeftOf="@+id/light_right_img"
            android:layout_toRightOf="@+id/light_img">

            <TextView
                android:id="@+id/light_set_tv"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:gravity="center_vertical"
                android:text="设定值:"
                android:textColor="#1fa433"
                android:textSize="15sp" />

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginLeft="15dp"
                android:layout_toRightOf="@+id/light_set_tv"
                android:gravity="center_vertical"
                android:text="200"
                android:textColor="#605858"
                android:textSize="15sp" />

        </RelativeLayout>

        <ImageView
            android:id="@+id/light_right_img"
            android:layout_width="20dp"
            android:layout_height="60dp"
            android:layout_alignParentRight="true"
            android:layout_centerVertical="true"
            android:src="@mipmap/right" />

        <ImageView
            android:id="@+id/light_warn_img"
            android:layout_width="50dp"
            android:layout_height="20dp"
            android:layout_alignParentRight="true"
            android:layout_alignParentTop="true"
            android:src="@mipmap/p2" />

    </RelativeLayout>

    <View
        android:layout_width="match_parent"
        android:layout_height="1dp"
        android:background="#716c6c"/>

</LinearLayout>

    <LinearLayout 
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    >

    <View
        android:layout_width="match_parent"
        android:layout_height="1dp"
        android:background="#716c6c"/>

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="5dp"
        >

        <com.makeramen.roundedimageview.RoundedImageView
            app:riv_oval="true"
            android:id="@+id/soil_img"
            android:layout_width="120dp"
            android:layout_height="120dp"
            android:src="@mipmap/turang" />

        <TextView
            android:id="@+id/soil_tv"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_alignTop="@+id/soil_img"
            android:layout_margin="5dp"
            android:layout_toLeftOf="@+id/soil_warn_img"
            android:layout_toRightOf="@+id/soil_img"
            android:text="土壤指数"
            android:textColor="#100909"
            android:textSize="20sp" />

        <RelativeLayout
            android:id="@+id/light_relative"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_below="@+id/soil_tv"
            android:layout_margin="5dp"
            android:layout_toLeftOf="@+id/soil_right_img"
            android:layout_toRightOf="@+id/soil_img">

            <TextView
                android:id="@+id/soil_temp_tv"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:gravity="center_vertical"
                android:text="温度:"
                android:textColor="#100909"
                android:textSize="20sp" />

            <TextView
                android:id="@+id/soil_temp_values_tv"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_toRightOf="@+id/soil_temp_tv"
                android:gravity="center_vertical"
                android:text="35"
                android:textColor="#e80c0c"
                android:textSize="20sp" />

            <TextView
                android:layout_toRightOf="@+id/soil_temp_values_tv"
                android:id="@+id/soil_wetness_tv"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:gravity="center_vertical"
                android:text="湿度:"
                android:textColor="#100909"
                android:textSize="20sp" />

            <TextView

                android:id="@+id/soil_wetness_values_tv"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_toRightOf="@+id/soil_wetness_tv"
                android:gravity="center_vertical"
                android:text="35"
                android:textColor="#e80c0c"
                android:textSize="20sp" />

        </RelativeLayout>

        <RelativeLayout
            android:id="@+id/soil_set_relative"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginLeft="5dp"
            android:layout_below="@+id/light_relative"
            android:layout_toLeftOf="@+id/soil_right_img"
            android:layout_toRightOf="@+id/soil_img">

            <TextView
                android:id="@+id/soil_temp_set_tv"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:gravity="center_vertical"
                android:text="温度设定值:"
                android:textColor="#1fa433"
                android:textSize="15sp" />

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginLeft="15dp"
                android:layout_toRightOf="@+id/soil_temp_set_tv"
                android:gravity="center_vertical"
                android:text="200"
                android:textColor="#605858"
                android:textSize="15sp" />

        </RelativeLayout>

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginLeft="5dp"
            android:layout_marginTop="5dp"
            android:layout_alignBottom="@+id/soil_img"
            android:layout_below="@+id/soil_set_relative"
            android:layout_toLeftOf="@+id/soil_right_img"
            android:layout_toRightOf="@+id/soil_img">

            <TextView
                android:id="@+id/soil_wetness_set_tv"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:gravity="center_vertical"
                android:text="湿度设定值:"
                android:textColor="#1fa433"
                android:textSize="15sp" />

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginLeft="15dp"
                android:layout_toRightOf="@+id/soil_wetness_set_tv"
                android:gravity="center_vertical"
                android:text="200"
                android:textColor="#605858"
                android:textSize="15sp" />

        </RelativeLayout>

        <ImageView
            android:id="@+id/soil_right_img"
            android:layout_width="20dp"
            android:layout_height="60dp"
            android:layout_alignParentRight="true"
            android:layout_centerVertical="true"
            android:src="@mipmap/right" />

        <ImageView
            android:id="@+id/soil_warn_img"
            android:layout_width="50dp"
            android:layout_height="20dp"
            android:layout_alignParentRight="true"
            android:layout_alignParentTop="true"
            android:src="@mipmap/p2" />

    </RelativeLayout>

    <View
        android:layout_width="match_parent"
        android:layout_height="1dp"
        android:background="#716c6c"/>
</LinearLayout>





<LinearLayout
    android:layout_width="match_parent"
    android:orientation="vertical"
    android:layout_height="wrap_content"
   >
    <View
        android:layout_width="match_parent"
        android:layout_height="1dp"
        android:background="#716c6c"/>

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="5dp"
        >

        <com.makeramen.roundedimageview.RoundedImageView
            app:riv_oval="true"
            android:id="@+id/soil_img"
            android:layout_width="120dp"
            android:layout_height="120dp"
            android:src="@mipmap/kongqi" />

        <TextView
            android:id="@+id/soil_tv"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_alignTop="@+id/soil_img"
            android:layout_margin="5dp"
            android:layout_toLeftOf="@+id/air_warn_img"
            android:layout_toRightOf="@+id/soil_img"
            android:text="空气指数"
            android:textColor="#100909"
            android:textSize="20sp" />

        <RelativeLayout
            android:id="@+id/light_relative"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_below="@+id/soil_tv"
            android:layout_margin="5dp"
            android:layout_toLeftOf="@+id/air_right_img"
            android:layout_toRightOf="@+id/soil_img">

            <TextView
                android:id="@+id/soil_temp_tv"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:gravity="center_vertical"
                android:text="温度:"
                android:textColor="#100909"
                android:textSize="20sp" />

            <TextView
                android:id="@+id/air_temp_values_tv"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_toRightOf="@+id/soil_temp_tv"
                android:gravity="center_vertical"
                android:text="35"
                android:textColor="#e80c0c"
                android:textSize="20sp" />

            <TextView
                android:layout_toRightOf="@+id/air_temp_values_tv"
                android:id="@+id/air_wetness_tv"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:gravity="center_vertical"
                android:text="湿度:"
                android:textColor="#100909"
                android:textSize="20sp" />

            <TextView

                android:id="@+id/air_wetness_values_tv"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_toRightOf="@+id/air_wetness_tv"
                android:gravity="center_vertical"
                android:text="35"
                android:textColor="#e80c0c"
                android:textSize="20sp" />

        </RelativeLayout>

        <RelativeLayout
            android:id="@+id/soil_set_relative"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginLeft="5dp"
            android:layout_below="@+id/light_relative"
            android:layout_toLeftOf="@+id/air_right_img"
            android:layout_toRightOf="@+id/soil_img">

            <TextView
                android:id="@+id/soil_temp_set_tv"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:gravity="center_vertical"
                android:text="温度设定值:"
                android:textColor="#1fa433"
                android:textSize="15sp" />

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginLeft="15dp"
                android:layout_toRightOf="@+id/soil_temp_set_tv"
                android:gravity="center_vertical"
                android:text="200"
                android:textColor="#605858"
                android:textSize="15sp" />

        </RelativeLayout>

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginLeft="5dp"
            android:layout_marginTop="5dp"
            android:layout_alignBottom="@+id/soil_img"
            android:layout_below="@+id/soil_set_relative"
            android:layout_toLeftOf="@+id/air_right_img"
            android:layout_toRightOf="@+id/soil_img">

            <TextView
                android:id="@+id/soil_wetness_set_tv"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:gravity="center_vertical"
                android:text="湿度设定值:"
                android:textColor="#1fa433"
                android:textSize="15sp" />

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginLeft="15dp"
                android:layout_toRightOf="@+id/soil_wetness_set_tv"
                android:gravity="center_vertical"
                android:text="200"
                android:textColor="#605858"
                android:textSize="15sp" />

        </RelativeLayout>

        <ImageView
            android:id="@+id/air_right_img"
            android:layout_width="20dp"
            android:layout_height="60dp"
            android:layout_alignParentRight="true"
            android:layout_centerVertical="true"
            android:src="@mipmap/right" />

        <ImageView
            android:id="@+id/air_warn_img"
            android:layout_width="50dp"
            android:layout_height="20dp"
            android:layout_alignParentRight="true"
            android:layout_alignParentTop="true"
            android:src="@mipmap/p2" />



    </RelativeLayout>
    <View
        android:layout_width="match_parent"
        android:layout_height="1dp"
        android:background="#716c6c"/>

</LinearLayout>
        </LinearLayout>
    </ScrollView>
</RelativeLayout>

HelpFragment、SettingFragment中的布局就不在展示。

• 创建适配器MyPAgerAdapter

public class MyPageAdapter extends FragmentPagerAdapter {
    //创建fragmentList集合
    private List<Fragment> fragmentList;
    //构造方法实现传值
    public MyPageAdapter(FragmentManager fm, List<Fragment> fragmentList) {
        super(fm);
        this.fragmentList = fragmentList;
    }
    //返回fragmentList对象
    @Override
    public Fragment getItem(int position) {
        return fragmentList.get(position);
    }
    //返回fragmentList对象个数
    @Override
    public int getCount() {
        return fragmentList.size();
    }
}

• 在MainActivity中绑定适配器，使得三个界面可以自由滑动。

HomePageFragment homePageFragment = new HomePageFragment();
        SetFragment setFragment = new SetFragment();
        HelpFragment helpFragment = new HelpFragment();
        fragmentList.add(homePageFragment);
        fragmentList.add(setFragment);
        fragmentList.add(helpFragment);
        MyPageAdapter adapter = new MyPageAdapter(getSupportFragmentManager(), fragmentList);
        agricultureVp.setAdapter(adapter);

3、首页对话框

在每次打开APP时，都会弹出一个对话框，提示输入服务器的IP地址。

• 在布局文件中先写好对话框的布局代码：

<TextView
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:textSize="20dp"
        android:text="欢迎您，请先设置服务器IP"
        android:gravity="center"/>
    <View
        android:layout_width="match_parent"
        android:layout_height="1dp"
        android:background="#716c6c"/>
    <EditText
        android:id="@+id/dialog_et"
        android:layout_width="match_parent"
        android:hint="请输入设备上显示的IP地址"
        android:padding="15dp"
        android:layout_height="50dp" />
    <View
        android:layout_width="match_parent"
        android:layout_height="1dp"
        android:background="#716c6c"/>
    <Button
        android:id="@+id/dialog_btn"
        android:layout_width="match_parent"
        android:layout_margin="15dp"
        android:text="确定"
        android:textSize="20sp"
        android:gravity="center"
        android:layout_gravity="center"
        android:layout_height="50dp"
        android:background="#63c999"
        />

• 在背景图片对应的Activity中创建对话框

   handler.postDelayed(new Runnable() {  
            //使用handler的postDelayed实现延时跳转

            public void run() {

                        AlertDialog.Builder builder = new AlertDialog.Builder(ImgActivity.this);
                        View view = View.inflate(ImgActivity.this,R.layout.alert_dialog,null);
                        builder.setView(view);
                        builder.setCancelable(true);
                        editText = view.findViewById(R.id.dialog_et);
                        button = view.findViewById(R.id.dialog_btn);
                        AlertDialog dialog = builder.create();
                        dialog.show();


                button.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        Intent intent = new Intent(ImgActivity.this, MainActivity.class);
                        IP = editText.getText().toString();
                        intent.putExtra("IP",IP);
                        startActivity(intent);
                        finish();
                    }
                });
            }
        }, SPLASH_LENGTH);
        //3秒后跳转至应用主界面MainActivity

• 接收IP地址
  在智能农业首页HomePagerFragment中接收IP地址：

Intent intent = getActivity().getIntent();
String relativeUrl = intent.getStringExtra("IP");

5、从HomePagerFragment中查看CO2、空气、土壤、光照详情

• 创建四个Activity——Co2Activity、AirActivity、SoilActivity、SunshineActivity。

• 从Fragment到Activity之间的通信与传值用如下语句：

  Intent intent = new Intent(getActivity(), CO2Activity.class);
                intent.putExtra("basicUrl",basicUrl);
                startActivity(intent);

6、CO2、空气、土壤、光照详情

布局文件就不再叙述。

• 创建Gson解析的实体类：

public class App {

    private int airHumidity;
    private int PM25;
    private int airTemperature;
    private int soilTemperature;
    private int co2;
    private int soilHumidity;
    private int light;

    public int getAirHumidity() {
        return airHumidity;
    }

    public void setAirHumidity(int airHumidity) {
        this.airHumidity = airHumidity;
    }

    public int getPM25() {
        return PM25;
    }

    public void setPM25(int PM25) {
        this.PM25 = PM25;
    }

    public int getAirTemperature() {
        return airTemperature;
    }

    public void setAirTemperature(int airTemperature) {
        this.airTemperature = airTemperature;
    }

    public int getSoilTemperature() {
        return soilTemperature;
    }

    public void setSoilTemperature(int soilTemperature) {
        this.soilTemperature = soilTemperature;
    }

    public int getCo2() {
        return co2;
    }

    public void setCo2(int co2) {
        this.co2 = co2;
    }

    public int getSoilHumidity() {
        return soilHumidity;
    }

    public void setSoilHumidity(int soilHumidity) {
        this.soilHumidity = soilHumidity;
    }

    public int getLight() {
        return light;
    }

    public void setLight(int light) {
        this.light = light;
    }
}

public class AppStatus {

    private int WaterPump;
    private int Blower;
    private int Roadlamp;
    private int Buzzer;
    private String result;

    public int getWaterPump() {
        return WaterPump;
    }

    public void setWaterPump(int waterPump) {
        WaterPump = waterPump;
    }

    public int getBlower() {
        return Blower;
    }

    public void setBlower(int blower) {
        Blower = blower;
    }

    public int getRoadlamp() {
        return Roadlamp;
    }

    public void setRoadlamp(int roadlamp) {
        Roadlamp = roadlamp;
    }

    public int getBuzzer() {
        return Buzzer;
    }

    public void setBuzzer(int buzzer) {
        Buzzer = buzzer;
    }

    public String getResult() {
        return result;
    }

    public void setResult(String result) {
        this.result = result;
    }
}

public class FanResult {

    private String result;

    public String getResult() {
        return result;
    }

    public void setResult(String result) {
        this.result = result;
    }
}

• 创建OKHttp用来请求网络的实体类：

public class Okhttp {

    private static OkHttpClient client = new OkHttpClient();

    public static void sendOkHttpRequest(String address,okhttp3.Callback callback){


        Request request = new Request.Builder().url(address).build();
        client.newCall(request).enqueue(callback);
    }

    public static void postJsonByOkHttp(String url, JSONObject jsonObject,okhttp3.Callback callback){

        MediaType mediaType = MediaType.parse("application/json;Charset=UTF-8");
        RequestBody requestBody = RequestBody.create(mediaType,jsonObject.toString());
        Request request = new Request.Builder().url(url).post(requestBody).build();
        client.newCall(request).enqueue(callback);
        }

• 把控制灯光、水泵、蜂鸣器、风扇封装在同一个类中。

public class Control {

    public static int Result = 0;
    public static int alertResult = 0;
    public static int lightResult = 0;
    public static int pumpResult = 0;
    //开风扇
    public static void openFan(String basicUrl, final Context context) {

        final JSONObject[] jsonObject = {new JSONObject()};
        try {
            jsonObject[0].put("Blower", 1);
        } catch (JSONException e) {
            e.printStackTrace();
        }
        Okhttp.postJsonByOkHttp(basicUrl +"control", jsonObject[0], new okhttp3.Callback() {
            @Override
            public void onFailure(Call call, IOException e) {
            }

            @Override
            public void onResponse(Call call, Response response) throws IOException {
                String responseString = response.body().string();
                try {
                    JSONObject jsonObject1 = new JSONObject(responseString);
                    if (jsonObject1.getString("result").equals("ok")) {
                        Status.Blower = 1;
                        Control.Result = 1;
                    }
                } catch (JSONException e) {
                    e.printStackTrace();
                }

            }
        });

    }
//关风扇
    public static void closeFan(String basicUrl, Context context) {
        final JSONObject[] jsonObject = {new JSONObject()};
        try {
            jsonObject[0].put("Blower", 0);
        } catch (JSONException e) {
            e.printStackTrace();
        }
        Okhttp.postJsonByOkHttp(basicUrl +"control", jsonObject[0], new okhttp3.Callback() {
            @Override
            public void onFailure(Call call, IOException e) {
            }

            @Override
            public void onResponse(Call call, Response response) throws IOException {
                String responseString = response.body().string();
                try {
                    JSONObject jsonObject1 = new JSONObject(responseString);
                    if (jsonObject1.getString("result").equals("ok")) {
                        Status.Blower = 0;
                        Control.Result = 0;
                    }
                } catch (JSONException e) {
                    e.printStackTrace();
                }

            }
        });
    }
//开蜂鸣器
    public static void openAlert(String basicUrl, Context context) {
        final JSONObject[] jsonObject = {new JSONObject()};
        try {
            jsonObject[0].put("Buzzer", 1);
        } catch (JSONException e) {
            e.printStackTrace();
        }
        Okhttp.postJsonByOkHttp(basicUrl +"control", jsonObject[0], new okhttp3.Callback() {
            @Override
            public void onFailure(Call call, IOException e) {
            }

            @Override
            public void onResponse(Call call, Response response) throws IOException {
                String responseString = response.body().string();
                try {
                    JSONObject jsonObject1 = new JSONObject(responseString);
                    if (jsonObject1.getString("result").equals("ok")) {
                        Control.alertResult = 1;
                        Status.Buzzer = 1;
                    }
                } catch (JSONException e) {
                    e.printStackTrace();
                }

            }
        });


    }
//关蜂鸣器
    public static void closeAlert(String basicUrl, Context context) {
        final JSONObject[] jsonObject = {new JSONObject()};
        try {
            jsonObject[0].put("Buzzer", 0);
        } catch (JSONException e) {
            e.printStackTrace();
        }
        Okhttp.postJsonByOkHttp(basicUrl +"control", jsonObject[0], new okhttp3.Callback() {
            @Override
            public void onFailure(Call call, IOException e) {
            }

            @Override
            public void onResponse(Call call, Response response) throws IOException {
                String responseString = response.body().string();
                try {
                    JSONObject jsonObject1 = new JSONObject(responseString);
                    if (jsonObject1.getString("result").equals("ok")) {
                        Control.alertResult = 0;
                        Status.Buzzer = 0;
                    }
                } catch (JSONException e) {
                    e.printStackTrace();
                }

            }
        });

    }
//开灯
    public static void openLight(String basicUrl, Context context) {
        final JSONObject[] jsonObject = {new JSONObject()};
        try {
            jsonObject[0].put("Roadlamp", 1);
        } catch (JSONException e) {
            e.printStackTrace();
        }
        Okhttp.postJsonByOkHttp(basicUrl +"control", jsonObject[0], new okhttp3.Callback() {
            @Override
            public void onFailure(Call call, IOException e) {
            }

            @Override
            public void onResponse(Call call, Response response) throws IOException {
                String responseString = response.body().string();
                try {
                    JSONObject jsonObject1 = new JSONObject(responseString);
                    if (jsonObject1.getString("result").equals("ok")) {
                        Control.lightResult = 1;
                        Status.Roadlamp = 1;
                    }
                } catch (JSONException e) {
                    e.printStackTrace();
                }

            }
        });


    }
//关灯
    public static void closeLight(String basicUrl, Context context) {
        final JSONObject[] jsonObject = {new JSONObject()};
        try {
            jsonObject[0].put("Roadlamp", 0);
        } catch (JSONException e) {
            e.printStackTrace();
        }
        Okhttp.postJsonByOkHttp(basicUrl +"control", jsonObject[0], new okhttp3.Callback() {
            @Override
            public void onFailure(Call call, IOException e) {
            }

            @Override
            public void onResponse(Call call, Response response) throws IOException {
                String responseString = response.body().string();
                try {
                    JSONObject jsonObject1 = new JSONObject(responseString);
                    if (jsonObject1.getString("result").equals("ok")) {
                        Control.lightResult = 0;
                        Status.Roadlamp = 0;
                    }
                } catch (JSONException e) {
                    e.printStackTrace();
                }

            }
        });

    }
//开水泵
    public static void openPump(String basicUrl, Context context) {
        final JSONObject[] jsonObject = {new JSONObject()};
        try {
            jsonObject[0].put("WaterPump", 1);
        } catch (JSONException e) {
            e.printStackTrace();
        }
        Okhttp.postJsonByOkHttp(basicUrl +"control", jsonObject[0], new okhttp3.Callback() {
            @Override
            public void onFailure(Call call, IOException e) {
            }

            @Override
            public void onResponse(Call call, Response response) throws IOException {
                String responseString = response.body().string();
                try {
                    JSONObject jsonObject1 = new JSONObject(responseString);
                    if (jsonObject1.getString("result").equals("ok")) {
                        Control.pumpResult = 1;
                        Status.WaterPump = 1;
                    }
                } catch (JSONException e) {
                    e.printStackTrace();
                }

            }
        });

    }
//关水泵
    public static void closePump(String basicUrl, Context context) {
        final JSONObject[] jsonObject = {new JSONObject()};
        try {
            jsonObject[0].put("WaterPump", 0);
        } catch (JSONException e) {
            e.printStackTrace();
        }
        Okhttp.postJsonByOkHttp(basicUrl +"control", jsonObject[0], new okhttp3.Callback() {
            @Override
            public void onFailure(Call call, IOException e) {
            }

            @Override
            public void onResponse(Call call, Response response) throws IOException {
                String responseString = response.body().string();
                try {
                    JSONObject jsonObject1 = new JSONObject(responseString);
                    if (jsonObject1.getString("result").equals("ok")) {
                        Control.pumpResult = 0;
                        Status.WaterPump = 0;
                    }
                } catch (JSONException e) {
                    e.printStackTrace();
                }

            }
        });

    }
}

• 创建一个标志位用来判断灯光、蜂鸣器、水泵、风扇是否呈关闭状态。

public class Status {
    public static int WaterPump = 0;
    public static int Blower = 0;
    public static int Roadlamp = 0;
    public static int Buzzer = 0;
    public static String resultStr;
    public  static String TAG = "Status";
}

• 最后，最重要的是在四个Activity中调用上面封装的类的开关。
  Co2Acvitity:

public class CO2Activity extends AppCompatActivity implements View.OnClickListener {

    private static final String TAG = "CO2Activity";
    private static ImageView openFanImg;
    private static ImageView openAlertImg;
    private TextView co2ValuseTv;


    private  void modifierBlowerStatus() {

        if (Status.Blower == 0) {
            openFanImg.setImageResource(R.mipmap.dakaifengshan);
            Control.Result = 0;
        } else if (Status.Blower == 1) {
            openFanImg.setImageResource(R.mipmap.dakaifengshan2);
            Control.Result = 1;
        }
    }

    private  void modifierBuzzerStatus() {
        if (Status.Buzzer == 0) {
            openAlertImg.setImageResource(R.mipmap.dakaibaojing);
            Control.alertResult = 0;
        } else if (Status.Buzzer == 1) {
            openAlertImg.setImageResource(R.mipmap.dakaibaojing2);
            Control.alertResult = 1;
        }
    }



    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_co2);

        bangID();
        modifierBlowerStatus();
        modifierBuzzerStatus();

        App app = new App();
        co2ValuseTv.setText(HomePageFragment.co2+"");

    }

    private void bangID() {
        openFanImg = findViewById(R.id.co2_open_fan_img);
        openAlertImg = findViewById(R.id.co2_openalert_img);
        co2ValuseTv = findViewById(R.id.co_values_tv);

        openFanImg.setOnClickListener(this);
        openAlertImg.setOnClickListener(this);

    }

    @Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.co2_open_fan_img:
                if (Control.Result == 0) {
                    openFanImg.setImageResource(R.mipmap.dakaifengshan2);
                    Intent intent = getIntent();
                    String basicUrl = intent.getStringExtra("basicUrl");
                    Control.openFan(basicUrl, CO2Activity.this);
                 } else if (Control.Result == 1) {
                    openFanImg.setImageResource(R.mipmap.dakaifengshan);
                    Intent intent = getIntent();
                    String basicUrl = intent.getStringExtra("basicUrl");
                    Control.closeFan(basicUrl, CO2Activity.this);
                 }
                break;
            case R.id.co2_openalert_img:
                if (Control.alertResult == 0) {
                    openAlertImg.setImageResource(R.mipmap.dakaibaojing2);
                    Intent intent = getIntent();
                    String basicUrl = intent.getStringExtra("basicUrl");
                    Control.openAlert(basicUrl, CO2Activity.this);
                 } else if (Control.alertResult == 1) {
                    openAlertImg.setImageResource(R.mipmap.dakaibaojing);
                    Intent intent = getIntent();
                    String basicUrl = intent.getStringExtra("basicUrl");
                    Control.closeAlert(basicUrl, CO2Activity.this);
                 }
                break;
        }
    }
}

SoilActivity:

public class SoilActivity extends AppCompatActivity implements View.OnClickListener{

    private static ImageView openPumpImg;
    private static ImageView openLightImg;
    private static ImageView openAlertImg;
    private TextView soilTemp;
    private TextView soilWet;

    private  void modifierPumpStatus() {
        if (Status.WaterPump == 0) {
            openPumpImg.setImageResource(R.mipmap.dakaishui);
            Control.pumpResult = 0;
        } else if (Status.WaterPump == 1) {
            openPumpImg.setImageResource(R.mipmap.dakaishui2);
            Control.pumpResult = 1;
        }
    }


    private  void modifierLightStatus() {
        if (Status.Roadlamp == 0) {
            openLightImg.setImageResource(R.mipmap.dakaiguangzhao);
            Control.lightResult = 0;
        } else if (Status.Roadlamp == 1) {
            openLightImg.setImageResource(R.mipmap.dakaiguangzhao2);
            Control.lightResult = 1;
        }
    }

    private  void modifierBuzzerStatus() {
        if (Status.Buzzer == 0) {
            openAlertImg.setImageResource(R.mipmap.dakaibaojing);
            Control.alertResult = 0;
        } else if (Status.Buzzer == 1) {
            openAlertImg.setImageResource(R.mipmap.dakaibaojing2);
            Control.alertResult = 1;
        }
    }



    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_soil);

        bangID();

        modifierPumpStatus();

        modifierLightStatus();

        modifierBuzzerStatus();

        soilWet.setText(HomePageFragment.soilHumidity+"");
        soilTemp.setText(HomePageFragment.soilTemperature+"");


    }

    private void bangID() {
        openPumpImg = findViewById(R.id.soil_WaterPump_img);
        openLightImg = findViewById(R.id.soil_light_img);
        openAlertImg = findViewById(R.id.soil_alert_img);
        soilTemp = findViewById(R.id.soil_temp_values);
        soilWet = findViewById(R.id.soil_wet_values);

        openPumpImg.setOnClickListener(this);
        openLightImg.setOnClickListener(this);
        openAlertImg.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {

        switch (v.getId()){
            case R.id.soil_WaterPump_img:
                if (Control.pumpResult == 0) {
                    openPumpImg.setImageResource(R.mipmap.dakaishui2);
                    Intent intent = getIntent();
                    String basicUrl = intent.getStringExtra("basicUrl");
                    Control.openPump(basicUrl, SoilActivity.this);
                  //  Toast.makeText(this, "开水泵", Toast.LENGTH_SHORT).show();
                } else if (Control.pumpResult == 1) {
                    openPumpImg.setImageResource(R.mipmap.dakaishui);
                    Intent intent = getIntent();
                    String basicUrl = intent.getStringExtra("basicUrl");
                    Control.closePump(basicUrl, SoilActivity.this);
                  //  Toast.makeText(this, "关水泵", Toast.LENGTH_SHORT).show();
                }
                break;
            case R.id.soil_light_img:
                if(Control.lightResult==0){
                    openLightImg.setImageResource(R.mipmap.dakaiguangzhao2);
                    Intent intent = getIntent();
                    String basicUrl = intent.getStringExtra("basicUrl");
                    Control.openLight(basicUrl,SoilActivity.this);
                  //  Toast.makeText(this, "开灯", Toast.LENGTH_SHORT).show();
                }else if( Control.lightResult==1){
                    openLightImg.setImageResource(R.mipmap.dakaiguangzhao);
                    Intent intent = getIntent();
                    String basicUrl = intent.getStringExtra("basicUrl");
                    Control.closeLight(basicUrl,SoilActivity.this);
                   // Toast.makeText(this, "关灯", Toast.LENGTH_SHORT).show();
                }
                break;
            case R.id.soil_alert_img:
                if (Control.alertResult == 0) {
                    openAlertImg.setImageResource(R.mipmap.dakaibaojing2);
                    Intent intent = getIntent();
                    String basicUrl = intent.getStringExtra("basicUrl");
                    Control.openAlert(basicUrl, SoilActivity.this);
                   // Toast.makeText(this, "开警报", Toast.LENGTH_SHORT).show();
                } else if (Control.alertResult == 1) {
                    openAlertImg.setImageResource(R.mipmap.dakaibaojing);
                    Intent intent = getIntent();
                    String basicUrl = intent.getStringExtra("basicUrl");
                    Control.closeAlert(basicUrl, SoilActivity.this);
                   // Toast.makeText(this, "关警报", Toast.LENGTH_SHORT).show();
                }
                break;
        }
    }
}

AirActivity:

public class AirActivity extends AppCompatActivity implements View.OnClickListener{

    private ImageView openFanImg;
    private ImageView openLightImg;
    private ImageView openPumpImg;
    private ImageView openAlertImg;
    private TextView airTemp;
    private TextView airWet;

    private  void modifierBlowerStatus() {
        if (Status.Blower == 0) {
            openFanImg.setImageResource(R.mipmap.dakaifengshan);
            Control.Result = 0;
        } else if (Status.Blower == 1) {
            openFanImg.setImageResource(R.mipmap.dakaifengshan2);
            Control.Result = 1;
        }
    }

    private  void modifierBuzzerStatus() {
        if (Status.Buzzer == 0) {
            openAlertImg.setImageResource(R.mipmap.dakaibaojing);
            Control.alertResult = 0;
        } else if (Status.Buzzer == 1) {
            openAlertImg.setImageResource(R.mipmap.dakaibaojing2);
            Control.alertResult = 1;
        }
    }

    private  void modifierLightStatus() {
        if (Status.Roadlamp == 0) {
            openLightImg.setImageResource(R.mipmap.dakaiguangzhao);
            Control.lightResult = 0;
        } else if (Status.Roadlamp == 1) {
            openLightImg.setImageResource(R.mipmap.dakaiguangzhao2);
            Control.lightResult = 1;
        }
    }

    private  void modifierPumpStatus() {
        if (Status.WaterPump == 0) {
            openPumpImg.setImageResource(R.mipmap.dakaishui);
            Control.pumpResult = 0;
        } else if (Status.WaterPump == 1) {
            openPumpImg.setImageResource(R.mipmap.dakaishui2);
            Control.pumpResult = 1;
        }
    }




    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_air);

        bangID();

        modifierBlowerStatus();
        modifierBuzzerStatus();
        modifierLightStatus();
        modifierPumpStatus();

        airTemp.setText(HomePageFragment.airTemperature+"");
        airWet.setText(HomePageFragment.airHumidity+"");

    }

    private void bangID() {
        openFanImg = findViewById(R.id.air_fan_img);
        openLightImg = findViewById(R.id.air_light_img);
        openPumpImg = findViewById(R.id.air_pump_img);
        openAlertImg = findViewById(R.id.air_alert_img);
        airTemp = findViewById(R.id.air_temp_values);
        airWet = findViewById(R.id.air_wet_values);

        openFanImg.setOnClickListener(this);
        openLightImg.setOnClickListener(this);
        openPumpImg.setOnClickListener(this);
        openAlertImg.setOnClickListener(this);

    }

    @Override
    public void onClick(View v) {
        switch (v.getId()){
            case R.id.air_alert_img:
                if (Control.alertResult == 0) {
                    openAlertImg.setImageResource(R.mipmap.dakaibaojing2);
                    Intent intent = getIntent();
                    String basicUrl = intent.getStringExtra("basicUrl");
                    Control.openAlert(basicUrl, AirActivity.this);
                 } else if (Control.alertResult == 1) {
                    openAlertImg.setImageResource(R.mipmap.dakaibaojing);
                    Intent intent = getIntent();
                    String basicUrl = intent.getStringExtra("basicUrl");
                    Control.closeAlert(basicUrl, AirActivity.this);
                 }
                break;
            case R.id.air_fan_img:
                if (Control.Result == 0) {
                    openFanImg.setImageResource(R.mipmap.dakaifengshan2);
                    Intent intent = getIntent();
                    String basicUrl = intent.getStringExtra("basicUrl");
                    Control.openFan(basicUrl, AirActivity.this);
                 } else if (Control.Result == 1) {
                    openFanImg.setImageResource(R.mipmap.dakaifengshan);
                    Intent intent = getIntent();
                    String basicUrl = intent.getStringExtra("basicUrl");
                    Control.closeFan(basicUrl, AirActivity.this);
                 }
                break;
            case R.id.air_light_img:
                if(Control.lightResult==0){
                    openLightImg.setImageResource(R.mipmap.dakaiguangzhao2);
                    Intent intent = getIntent();
                    String basicUrl = intent.getStringExtra("basicUrl");
                    Control.openLight(basicUrl,AirActivity.this);
                 }else if( Control.lightResult==1){
                    openLightImg.setImageResource(R.mipmap.dakaiguangzhao);
                    Intent intent = getIntent();
                    String basicUrl = intent.getStringExtra("basicUrl");
                    Control.closeLight(basicUrl,AirActivity.this);
                 }
                break;
            case R.id.air_pump_img:
                if (Control.pumpResult == 0) {
                    openPumpImg.setImageResource(R.mipmap.dakaishui2);
                    Intent intent = getIntent();
                    String basicUrl = intent.getStringExtra("basicUrl");
                    Control.openPump(basicUrl, AirActivity.this);
                 } else if (Control.pumpResult == 1) {
                    openPumpImg.setImageResource(R.mipmap.dakaishui);
                    Intent intent = getIntent();
                    String basicUrl = intent.getStringExtra("basicUrl");
                    Control.closePump(basicUrl, AirActivity.this);
                 }
                break;
        }
    }
}

LightActivity：

public class LightActivity extends AppCompatActivity implements View.OnClickListener{


    private static ImageView opneLightImg;
    private static ImageView opneAlertImg;
    private TextView lightTv;

    private  void modifierLightStatus() {
        if (Status.Roadlamp == 0) {
            opneLightImg.setImageResource(R.mipmap.dakaiguangzhao);
            Control.lightResult = 0;
        } else if (Status.Roadlamp == 1) {
            opneLightImg.setImageResource(R.mipmap.dakaiguangzhao2);
            Control.lightResult = 1;
        }
    }

    private  void modifierBuzzerStatus() {
        if (Status.Buzzer == 0) {
            opneAlertImg.setImageResource(R.mipmap.dakaibaojing);
            Control.alertResult = 0;
        } else if (Status.Buzzer == 1) {
            opneAlertImg.setImageResource(R.mipmap.dakaibaojing2);
            Control.alertResult = 1;
        }
    }



    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_light);

        bangID();

        modifierLightStatus();
        modifierBuzzerStatus();
        App app = new App();
        lightTv.setText(HomePageFragment.light+"");

    }



    private void bangID() {

        opneLightImg = findViewById(R.id.light_openLight_img);
        opneAlertImg = findViewById(R.id.light_alert_img);
        lightTv = findViewById(R.id.light_values_tv2);

        opneLightImg.setOnClickListener(this);
        opneAlertImg.setOnClickListener(this);

    }

    @Override
    public void onClick(View v) {
        switch (v.getId()){
            case R.id.light_openLight_img:
                if(Control.lightResult==0){
                    opneLightImg.setImageResource(R.mipmap.dakaiguangzhao2);
                    Intent intent = getIntent();
                    String basicUrl = intent.getStringExtra("basicUrl");
                    Control.openLight(basicUrl,LightActivity.this);
                 }else if( Control.lightResult==1){
                    opneLightImg.setImageResource(R.mipmap.dakaiguangzhao);
                    Intent intent = getIntent();
                    String basicUrl = intent.getStringExtra("basicUrl");
                    Control.closeLight(basicUrl,LightActivity.this);
                 }
                break;
            case R.id.light_alert_img:
                if (Control.alertResult == 0) {
                    opneAlertImg.setImageResource(R.mipmap.dakaibaojing2);
                    Intent intent = getIntent();
                    String basicUrl = intent.getStringExtra("basicUrl");
                    Control.openAlert(basicUrl, LightActivity.this);
                 } else if (Control.alertResult == 1) {
                    opneAlertImg.setImageResource(R.mipmap.dakaibaojing);
                    Intent intent = getIntent();
                    String basicUrl = intent.getStringExtra("basicUrl");
                    Control.closeAlert(basicUrl,LightActivity.this);
                 }
                break;
      }
    }
}

三、OkHttp使用

1、网络请求原理：

2、创建OKHttp实例：

三种创建实例的方法：

创建一个默认配置OkHttpClient，可以使用默认的构造函数。
通过new OkHttpClient.Builder()方法来一步一步配置一个OkHttpClient实例。
如果要求使用现有的实例，可以通过newBuilder()方法来进行构造。

• request
  简单看一下Request类，可以发现它代表一个Http请求，需要注意的是Request一旦build()之后，便不可修改。

• response
  Response代表一个Http的响应，这个类的实例不可修改。

• 发起请求
  跟到newCall()方法中发现，又使用OkHttpClient实例和Request的实例，一起构造了一个RealCall的实例。RealCall类简单做了一个托管并通过Dispather类对请求进行分发和执行，实际开启线程发起请求的方法就在这个类中。随后又调用execute()方法，拿到了一个响应。这个execute()方法，实际上执行的就是RealCall中的execute()方法，最后调用了Dispatcher的execute()方法。
• 两个需要注意的点：
  okhttp3不能在ui线程中运行
  onresponse在子线程中，需要用handler回调才能操作ui

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over~