Android-01活动

活动1

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

public class FirstActivity extends AppCompatActivity {


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.first_layout);
        Button button1=(Button) findViewById(R.id.button_1);    //findViewById()返回的是一个view对象，需要转化成Button对象
        button1.setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View v){
                String data="哈喽 活动2";
                Toast.makeText(FirstActivity.this,"You clickes button",
                        Toast.LENGTH_SHORT).show(); //LENGTH_LONG显示时间长
                Intent intent=new Intent("com.ldxiaofeng.android.myapplication01.ACTION_START");//Intent用于启动活动
                intent.addCategory("com.ldxiaofeng.android.myapplication01.MY_CATEGORY");
                intent.putExtra("extra_data",data);//putExtra()传递数据 第一个参数是键，第二个是真正要传的数据
                //startActivity(intent);//启动Intent的方法
                startActivityForResult(intent,1);//也可以启动活动，这个方法期望下个活动（活动2）销毁时能够返回一个结果给活动1
            }
        });
    }
    @Override//菜单部分
    public boolean onCreateOptionsMenu(Menu menu){
        getMenuInflater().inflate(R.menu.main,menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()){
            case R.id.add_item:
                Toast.makeText(this,"添加",Toast.LENGTH_SHORT).show();
                break;
            case R.id.remove_item:
                Toast.makeText(this,"移除",Toast.LENGTH_SHORT).show();
                break;
            case R.id.return_item:
                finish();
                break;
            default:
        }
        return true;
    }
    //用来接收活动二销毁后传输回来的数据
    //用startActivityForResult（）创建的活动被销毁后都会返回到onActivityResult()，根据返回的值resultCode 确定数据来源
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        switch (requestCode){
            case 1:
                if(resultCode==RESULT_OK){
                    String returnedData = data.getStringExtra("data_return");
                    Log.d("FirstActivity",returnedData);
                }
        }
    }
} 

活动一布局

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent">

    <Button
        android:id="@+id/button_1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Button 1"/>
</LinearLayout>

    menu

<menu xmlns:android="http://schemas.android.com/apk/res/android">
    <item
        android:id="@+id/add_item"
        android:title="Add"/>
    <item
        android:id="@+id/remove_item"
        android:title="Remove"/>
    <item
        android:id="@+id/return_item"
        android:title="退出"/>
</menu>

活动2

import android.content.Intent;
import android.net.Uri;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;

public class SecondActivity extends AppCompatActivity {

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

        Intent intent=getIntent();
        String data=intent.getStringExtra("extra_data");//getStringExtra()获取传递的数据 整形:getIntExtra()类推
        Log.d("SecondActivity",data);

        Button button2=(Button) findViewById(R.id.button_2);
        button2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent=new Intent(Intent.ACTION_VIEW);
                intent.setData(Uri.parse("http://www.baidu.com"));  //打开浏览器
                startActivity(intent);
            }
        });
        Button button4=(Button) findViewById(R.id.button_4);
        button4.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent=new Intent(Intent.ACTION_DIAL);
                intent.setData(Uri.parse("tel:10086")); //拨号
                startActivity(intent);
            }
        });
        Button button5=(Button) findViewById(R.id.button_5);
        button5.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent=new Intent();
                intent.putExtra("data_return","哈喽 活动1");
                setResult(RESULT_OK,intent);//用于向上一个活动返回数据
                finish();
            }
        });
    }

    //用户通过按返回键返回上个活动，传回数据
    @Override
    public void onBackPressed() {
        Intent intent=new Intent();
        intent.putExtra("data_return","哈喽 活动1");
        setResult(RESULT_OK,intent);//用于向上一个活动返回数据
        finish();
    }
} 

活动2布局

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <Button
        android:id="@+id/button_2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="网页"/>
    <Button
        android:id="@+id/button_4"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="拨号"/>
    <Button
        android:id="@+id/button_5"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="返回数据"/>
</LinearLayout>

活动3

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Gravity;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

public class ThirdActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.third_layout);
        Button button3=(Button) findViewById(R.id.button_3);
        button3.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Toast toast = Toast.makeText(ThirdActivity.this, "You clickes button 3",
                        Toast.LENGTH_LONG);
                toast.setGravity(Gravity.CENTER,0,0);
                toast.show();
            }
        });
    }
} 

活动三布局

<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <Button
        android:id="@+id/button_3"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Button 3"/>

</android.support.constraint.ConstraintLayout>

AndroidManifest.xml

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.ldxiaofeng.android.myapplication01">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity
            android:name=".FirstActivity"
            android:label="XF FirstActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity android:name=".SecondActivity"
            android:label="XF SecondActivity">
            <intent-filter>
                <action android:name="com.ldxiaofeng.android.myapplication01.ACTION_START" />
                <category android:name="android.intent.category.DEFAULT" />
                <category android:name="com.ldxiaofeng.android.myapplication01.MY_CATEGORY" />
            </intent-filter>
        </activity>
        <activity android:name=".ThirdActivity"
            android:label="XF ThirdActivity">
            <intent-filter>
                <action android:name="android.intent.action.VIEW"/>
                <category android:name="android.intent.category.DEFAULT"/>
                <data android:scheme="http"/>
            </intent-filter>
        </activity>
    </application>

</manifest>