7.高级UI组件

进度条

<ProgressBar
        android:id="@+id/p1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        style="@android:style/Widget.ProgressBar.Horizontal"
        android:max="100"/>

package com.example.myapplication;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.os.SystemClock;
import android.view.View;
import android.widget.Chronometer;
import android.widget.DatePicker;
import android.widget.ProgressBar;
import android.widget.TimePicker;
import android.widget.Toast;

import java.util.Calendar;

public class MainActivity extends AppCompatActivity {
   private ProgressBar progressBar;
   //记录进度条完成进度
   private int mPrograss = 0;
   private Handler mHandler;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        progressBar = findViewById(R.id.p1);
        //实例化一个处理消息的handler类
        mHandler = new Handler(){
            @Override
            public void handleMessage(@NonNull Message msg) {
                super.handleMessage(msg);
                if(msg.what==0x111){
                    progressBar.setProgress(mPrograss);
                }
                else{
                    Toast.makeText(MainActivity.this,"耗时操作已完成",Toast.LENGTH_SHORT).show();
                    progressBar.setVisibility(View.GONE);
                }

            }
        };
        new Thread(new Runnable() {
            @Override
            public void run() {
                while(true){
                    mPrograss=doWork();
                    Message m = new Message();
                    if (mPrograss<100){
                        m.what=0x111;
                        mHandler.sendMessage(m);
                    }
                    else{
                        m.what=0x110;
                        mHandler.sendMessage(m);
                        break;
                    }
                }
            }
            //模拟耗时操作
            private int doWork(){
                mPrograss+=Math.random()*10;
                try {
                    Thread.sleep(200);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                return mPrograss;
            }
        }).start();

    }

}

拖动条

<SeekBar
        android:id="@+id/S1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:max="10"
        android:progress="5"
        android:thumb="@drawable/abc_vector_test"/>

package com.example.seekbarp;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.widget.SeekBar;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        SeekBar seekBar = findViewById(R.id.S1);
        //拖动条的监听器
        seekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
            //进度改变执行的方法
            @Override
            public void onProgressChanged(SeekBar seekBar, int i, boolean b) {
                Toast.makeText(MainActivity.this,"进度条改变："+i,Toast.LENGTH_SHORT).show();
            }
            //开始触摸时候执行的方法
            @Override
            public void onStartTrackingTouch(SeekBar seekBar) {
                Toast.makeText(MainActivity.this,"开始触摸",Toast.LENGTH_SHORT).show();
            }
            //停止触摸时执行的方法
            @Override
            public void onStopTrackingTouch(SeekBar seekBar) {
                Toast.makeText(MainActivity.this,"停止触摸",Toast.LENGTH_SHORT).show();
            }
        });
    }
}

图像切换器

 <ImageSwitcher
        android:id="@+id/i1"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        />

package com.example.seekbarp;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.view.animation.AnimationUtils;
import android.widget.ImageSwitcher;
import android.widget.ImageView;
import android.widget.RatingBar;
import android.widget.SeekBar;
import android.widget.Toast;
import android.widget.ViewSwitcher;

public class MainActivity extends AppCompatActivity {
    ImageSwitcher is;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        is = findViewById(R.id.i1);
        //设置出现效果
        is.setOutAnimation(AnimationUtils.loadAnimation(MainActivity.this,android.R.anim.fade_out));
        //设置进入效果
        is.setInAnimation(AnimationUtils.loadAnimation(MainActivity.this,android.R.anim.fade_in));
        //指定视图工厂
        is.setFactory(new ViewSwitcher.ViewFactory() {
            @Override
            public View makeView() {
                ImageView imageView = new ImageView(MainActivity.this);
                imageView.setImageResource(R.drawable.m1);
                return imageView;
            }
        });
        is.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                ((ImageSwitcher)view).setImageResource(R.drawable.m2);
            }
        });
    }
}

下拉列表框

android:entries用来指定下拉列表项。
第一种法法：
属性值使用的是一个数组资源，需要在values中创建数组资源文件。

<Spinner
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:entries="@array/ctype"/>

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <string-array name="ctype">
        <item>全部</item>
        <item>苹果</item>
        <item>香蕉</item>
        <item>菠萝</item>
    </string-array>
</resources>

第二种法法：指定是适配器

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello World!"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <Spinner
        android:id="@+id/s1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        />

</androidx.constraintlayout.widget.ConstraintLayout>

package com.example.xialaliebiao;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
    Spinner spinner;
    String result;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        spinner = findViewById(R.id.s1);
        String []ctype = new String[]{"苹果","香蕉","橘子","葡萄"};
        ArrayAdapter<String> adapter = new ArrayAdapter<>(this,android.R.layout.simple_spinner_item,ctype);
        //为适配器设置列表框下拉时的样式
        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        spinner.setAdapter(adapter);
        //可以获取下拉列表框的选中值
        String str = spinner.getSelectedItem().toString();
        spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) {
                String result = adapterView.getItemAtPosition(i).toString();
                Toast.makeText(MainActivity.this,result,Toast.LENGTH_SHORT).show();
            }

            @Override
            public void onNothingSelected(AdapterView<?> adapterView) {

            }
        });
    }
}

列表视图

第一种法法同上
第二种方法：使用适配器

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <ListView
        android:id="@+id/l1"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        />

</androidx.constraintlayout.widget.ConstraintLayout>

package com.example.list;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.widget.ArrayAdapter;
import android.widget.ListView;

public class MainActivity extends AppCompatActivity {
    ListView listView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        String []ctype = new String[]{"苹果","鸭梨","橘子","香蕉"};
        ArrayAdapter<String> adapter = new ArrayAdapter<>(this,android.R.layout.simple_list_item_1,ctype);
        listView = findViewById(R.id.l1);
        listView.setAdapter(adapter);
    }
}

定制ListView的界面
一：定义一个实体类，作为ListView适配器的适配类型

package com.example.list;

public class Fruit {
    
    private String name;
    private int imageId;
    
    //定义Fruit类的构造方法
    public Fruit(String name,int imageId){
        this.name = name;
        this.imageId = imageId;
    }

    public String getName() {
        return name;
    }

    public int getImageId() {
        return imageId;
    }
}

二：为ListView子项指定一个我们自定义的布局

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="horizontal"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <ImageView
        android:id="@+id/i1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"

        />
    <TextView
        android:id="@+id/t1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="center_vertical"
        />
</LinearLayout>

三：自定义适配器

package com.example.list;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.TextView;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;

import java.util.List;

public class FruitAdapter extends ArrayAdapter {

    private int resouseId;
    public FruitAdapter(@NonNull Context context, int resource, @NonNull List objects) {
        super(context, resource, objects);
        resouseId = resource;
    }

    @NonNull
    @Override
    public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
        //获取当前Fruit实例
        Fruit fruit = (Fruit) getItem(position);
        View view = LayoutInflater.from(getContext()).inflate(resouseId,parent,false);
        ImageView fruitImage = view.findViewById(R.id.i1);
        TextView fruitName = view.findViewById(R.id.t1);
        fruitImage.setImageResource(fruit.getImageId());
        fruitName.setText(fruit.getName());
        return view;
    }
}

四：Activity_main

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

   <ListView
       android:id="@+id/l1"
       android:layout_width="match_parent"
       android:layout_height="match_parent"

       />

</androidx.constraintlayout.widget.ConstraintLayout>

五：MainActivity

package com.example.list;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.widget.ArrayAdapter;
import android.widget.ListView;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {
    private List<Fruit> fruitList = new ArrayList<>();
    ListView l1;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initFruit();
        FruitAdapter adapter = new FruitAdapter(MainActivity.this,R.layout.fruit_item,fruitList);
        l1 = findViewById(R.id.l1);
        l1.setAdapter(adapter);

    }

    private void initFruit(){
         for(int i = 0;i<11;i++){
             Fruit apple = new Fruit("Apple",R.drawable.shuiguo);
             fruitList.add(apple);
             Fruit banana = new Fruit("Banana",R.drawable.shuiguo);
             fruitList.add(banana);
         }
    }
}

滚动视图

选项卡