Select change event OnCheckedChange

1. Rendering: choose the correct prompt to choose the right, choose the wrong prompt to choose the wrong

2.activity_main.xml

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 3     xmlns:tools="http://schemas.android.com/tools"
 4     android:layout_width="match_parent"
 5     android:layout_height="match_parent"
 6    android:orientation="vertical"
 7     tools:context="com.example.app5.MainActivity">
 8 
 9     <TextView
10         android:layout_width="wrap_content"
11         android:layout_height="wrap_content"
12         android:text="请选择正确的题目" />
13     <RadioGroup
14         android:id="@+id/rg"
15         android:layout_width="wrap_content"
16         android:layout_height="wrap_content">
17         <RadioButton
18             android:id="@+id/rb_1"
19             android:text="1+1=3"
20             android:layout_width="wrap_content"
21             android:layout_height="wrap_content" />
22         <RadioButton
23             android:id="@+id/rb_2"
24             android:text="1+1=2"
25             android:layout_width="wrap_content"
26             android:layout_height="wrap_content" />
27         <RadioButton
28             android:id="@+id/rb_3"
29             android:text="1+1=4"
30             android:layout_width="wrap_content"
31             android:layout_height="wrap_content" />
32         <RadioButton
33             android:id="@+id/rb_4"
34             android:text="1+1=5"
35             android:layout_width="wrap_content"
36             android:layout_height="wrap_content" />
37 
38     </RadioGroup>
39 </LinearLayout>

2.MainActivity.java

 1 package com.example.app5;
 2 
 3 import android.support.v7.app.AppCompatActivity;
 4 import android.os.Bundle;
 5 import android.widget.RadioButton;
 6 import android.widget.RadioGroup;
 7 import android.widget.Toast;
 8 
 9 public class MainActivity extends AppCompatActivity {
10     private RadioGroup rg;
11     private RadioButton rb_1,rb_2,rb_3,rb_4;
12 
13     @Override
14     protected void onCreate(Bundle savedInstanceState) {
15         super.onCreate(savedInstanceState);
16         setContentView(R.layout.activity_main);
17         rg=(RadioGroup)findViewById(R.id.rg);
18         rb_1 = (RadioButton) findViewById(R.id.rb_1);
19         rb_2 = (RadioButton) findViewById(R.id.rb_2);
20         rb_3= (RadioButton) findViewById(R.id.rb_3);
21         rb_4 = (RadioButton) findViewById(R.id.rb_4);
22 
23         rg.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
24             @Override
25             public void onCheckedChanged(RadioGroup group, int checkedId) {
26 
27                 //switch实现方式
28                 /*switch (checkedId){
29                     case R.id.rb_1:
30                         Toast.makeText(MainActivity.this,"您选错了"+rb_1.isChecked(),Toast.LENGTH_SHORT).show();
31                         break;
32                     case R.id.rb_2:
33                         Toast.makeText(MainActivity.this,"您选对了"+rb_2.isChecked(),Toast.LENGTH_SHORT).show();
34                         break;
35                     case R.id.rb_3:
36                         Toast.makeText(MainActivity.this,"您选错了"+rb_3.isChecked(),Toast.LENGTH_SHORT).show();
37                         break;
38                     case R.id.rb_4:
39                         Toast.makeText(MainActivity.this,"您选错了"+rb_4.isChecked(),Toast.LENGTH_SHORT).show();
40                         break;*/
41 
42                  //if 判断实现方式
43               /*  if(R.id.rb_2==checkedId){
44                     Toast.makeText(MainActivity.this,"正确"+rb_2.isChecked(),Toast.LENGTH_SHORT).show();
45                 } else {
46                     Toast.makeText(MainActivity.this,"错误",Toast.LENGTH_SHORT).show();
47                 }*/
48 
49                 //对象的实现方式
50                 RadioButton r = (RadioButton) findViewById(checkedId);
51                 if(r.equals(rb_2)){
52                     Toast.makeText(MainActivity.this,"正确"+rb_2.isChecked(),Toast.LENGTH_SHORT).show();
53                 }else{
54                     Toast.makeText(MainActivity.this,"错误",Toast.LENGTH_SHORT).show();
55                 }
56             }
57         });
58 
59 
60     }
61 }