选择改变事件OnCheckedChange

1.效果图：选择正确的提示选对，选择错误提示选错

2.activity_main.xml

 <?xml version="1.0" encoding="utf-8"?>
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
    android:orientation="vertical"
     tools:context="com.example.app5.MainActivity">

     <TextView
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:text="请选择正确的题目" />
     <RadioGroup
         android:id="@+id/rg"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content">
         <RadioButton
             android:id="@+id/rb_1"
             android:text="1+1=3"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content" />
         <RadioButton
             android:id="@+id/rb_2"
             android:text="1+1=2"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content" />
         <RadioButton
             android:id="@+id/rb_3"
             android:text="1+1=4"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content" />
         <RadioButton
             android:id="@+id/rb_4"
             android:text="1+1=5"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content" />

     </RadioGroup>
 </LinearLayout>

2.MainActivity.java

 package com.example.app5;

 import android.support.v7.app.AppCompatActivity;
 import android.os.Bundle;
 import android.widget.RadioButton;
 import android.widget.RadioGroup;
 import android.widget.Toast;

 public class MainActivity extends AppCompatActivity {
     private RadioGroup rg;
     private RadioButton rb_1,rb_2,rb_3,rb_4;

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
         rg=(RadioGroup)findViewById(R.id.rg);
         rb_1 = (RadioButton) findViewById(R.id.rb_1);
         rb_2 = (RadioButton) findViewById(R.id.rb_2);
         rb_3= (RadioButton) findViewById(R.id.rb_3);
         rb_4 = (RadioButton) findViewById(R.id.rb_4);

         rg.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
             @Override
             public void onCheckedChanged(RadioGroup group, int checkedId) {

                 //switch实现方式
                 /*switch (checkedId){
                     case R.id.rb_1:
                         Toast.makeText(MainActivity.this,"您选错了"+rb_1.isChecked(),Toast.LENGTH_SHORT).show();
                         break;
                     case R.id.rb_2:
                         Toast.makeText(MainActivity.this,"您选对了"+rb_2.isChecked(),Toast.LENGTH_SHORT).show();
                         break;
                     case R.id.rb_3:
                         Toast.makeText(MainActivity.this,"您选错了"+rb_3.isChecked(),Toast.LENGTH_SHORT).show();
                         break;
                     case R.id.rb_4:
                         Toast.makeText(MainActivity.this,"您选错了"+rb_4.isChecked(),Toast.LENGTH_SHORT).show();
                         break;*/

                  //if 判断实现方式
               /*  if(R.id.rb_2==checkedId){
                     Toast.makeText(MainActivity.this,"正确"+rb_2.isChecked(),Toast.LENGTH_SHORT).show();
                 } else {
                     Toast.makeText(MainActivity.this,"错误",Toast.LENGTH_SHORT).show();
                 }*/

                 //对象的实现方式
                 RadioButton r = (RadioButton) findViewById(checkedId);
                 if(r.equals(rb_2)){
                     Toast.makeText(MainActivity.this,"正确"+rb_2.isChecked(),Toast.LENGTH_SHORT).show();
                 }else{
                     Toast.makeText(MainActivity.this,"错误",Toast.LENGTH_SHORT).show();
                 }
             }
         });

     }
 }

2.效果图：多选按钮，选择哪个之后提示选择了XX

（1）activity_main.xml

 <?xml version="1.0" encoding="utf-8"?>
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
    android:orientation="vertical"
     tools:context="com.example.app6.MainActivity">

     <TextView
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:text="您的爱好是" />
     <CheckBox
         android:id="@+id/cb_1"
         android:text="sing"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content" />
     <CheckBox
         android:id="@+id/cb_2"
         android:text="game"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content" />
     <CheckBox
         android:id="@+id/cb_3"
         android:text="eat food"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content" />

 </LinearLayout>

(2)MainActivity.java

 package com.example.app6;

 import android.support.v7.app.AppCompatActivity;
 import android.os.Bundle;
 import android.widget.CheckBox;
 import android.widget.CompoundButton;
 import android.widget.Toast;

 public class MainActivity extends AppCompatActivity {

     private CheckBox cb_1,cb_2,cb_3;
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
         cb_1=(CheckBox)findViewById(R.id.cb_1);
         cb_2=(CheckBox)findViewById(R.id.cb_2);
         cb_3=(CheckBox)findViewById(R.id.cb_3);

         cb_1.setOnCheckedChangeListener(new myListener());
         cb_2.setOnCheckedChangeListener(new myListener());
         cb_3.setOnCheckedChangeListener(new myListener());

     }
    class myListener implements CompoundButton.OnCheckedChangeListener {

        @Override
        public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {

            //switch实现
           /* switch (buttonView.getId()){
                case R.id.cb_1:
                    Toast.makeText(MainActivity.this,cb_1.getText().toString()+"  "+((CheckBox)buttonView).isChecked() ,Toast.LENGTH_SHORT).show();
                    break;
                case R.id.cb_2:
                    Toast.makeText(MainActivity.this,cb_2.getText().toString()+"  "+((CheckBox)buttonView).isChecked() ,Toast.LENGTH_SHORT).show();
                     break;
                case R.id.cb_3:
                    Toast.makeText(MainActivity.this,cb_3.getText().toString()+"  "+((CheckBox)buttonView).isChecked() ,Toast.LENGTH_SHORT).show();
                     break;
            }*/

            //if实现
            if(isChecked){
                Toast.makeText(MainActivity.this,buttonView.getText().toString()+"  "+(buttonView).isChecked() ,Toast.LENGTH_SHORT).show();
            } else{
                Toast.makeText(MainActivity.this,buttonView.getText().toString()+"  "+(buttonView).isChecked() ,Toast.LENGTH_SHORT).show();

            }
        }
    }
 }

3.效果图

（1）activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.app7.MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="您的爱好是" />
    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal">
        <CheckBox
            android:id="@+id/sing"
            android:text="sing"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" />
        <CheckBox
            android:id="@+id/game"
            android:text="game"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" />
        <CheckBox
            android:id="@+id/eat"
            android:text="eat"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" />
    </LinearLayout>
    <Button
        android:id="@+id/bt"
        android:text="提交"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />
</LinearLayout>

(2)MainAcivity.xml

 package com.example.app7;

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

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

 public class MainActivity extends AppCompatActivity {
     private Button bt;
     private CheckBox sing;
     private  CheckBox game;
     private  CheckBox eat;
     private List<CheckBox> list;
     private int count=0;

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

         sing = (CheckBox) findViewById(R.id.sing);
         game = (CheckBox) findViewById(R.id.game);
         eat = (CheckBox) findViewById(R.id.eat);
         bt = (Button) findViewById(R.id.bt);
         list = new ArrayList<>();
         list.add(sing);
         list.add(game);
         list.add(eat);

         bt.setOnClickListener(new View.OnClickListener() {
             @Override
             public void onClick(View v) {
                 StringBuffer sb = new StringBuffer();;
                 for (CheckBox checkbox:list){
                     if (checkbox.isChecked()){
                         count++;
                         sb.append(checkbox.getText().toString()+"  ");
                     }
                 }
                 if(sb==null||"".equals(sb.toString())){
                     Toast.makeText(MainActivity.this,"至少选择一项",Toast.LENGTH_SHORT).show();
                 }else {
                     Toast.makeText(MainActivity.this,sb.toString()+",共"+count+"项",Toast.LENGTH_SHORT).show();
                     count=0;
                 }
             }
         });
     }
 }