OnChencedChang

（一）

1,布局

<?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:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:orientation="vertical"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="helloworld.com.inspur.app5.MainActivity">

    <TextView android:layout_width="wrap_content"
        android:id="@+id/tv"
        android:layout_height="wrap_content"
        android:text="选择正确答案：" />
    <RadioGroup
        android:id="@+id/rg"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content">
        <RadioButton
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:id="@+id/rb1"
            android:text="2+1=2"/>
        <RadioButton
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:id="@+id/rb2"
            android:text="2+1=3"/>
        <RadioButton
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/rb3"
        android:text="2+1=4"/>
        <RadioButton
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:id="@+id/rb4"
            android:text="2+1=1"/>

    </RadioGroup>

</LinearLayout>

注意事项：RadioButton需要包含在RadioGroup内部才能实现单选的效果

2，逻辑代码的处理

package helloworld.com.inspur.app5;

import android.support.v4.widget.TextViewCompat;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
    private TextView tv;
    private RadioGroup rg;
    private RadioButton rb1;
    private RadioButton rb2;
    private RadioButton rb4;
    private RadioButton rb3;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        tv=(TextView)findViewById(R.id.tv);
        rg=(RadioGroup)findViewById(R.id.rg);
        rb1=(RadioButton)findViewById(R.id.rb1);
        rb2=(RadioButton)findViewById(R.id.rb2);
        rb4=(RadioButton)findViewById(R.id.rb4);
        rb3=(RadioButton)findViewById(R.id.rb3);
        rg.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(RadioGroup group, int checkedId) {
                switch (checkedId)
                {
                    case R.id.rb1:
                        Toast.makeText(MainActivity.this,"false",Toast.LENGTH_LONG).show();

                        break;
                    case R.id.rb2:
                        Toast.makeText(MainActivity.this,"true",Toast.LENGTH_LONG).show();
                        break;
                    case R.id.rb3:
                    Toast.makeText(MainActivity.this,"false",Toast.LENGTH_LONG).show();
                    break;
                    case R.id.rb4:
                        Toast.makeText(MainActivity.this,"false",Toast.LENGTH_LONG).show();
                        break;

                }
            }
        });

    }
}

注意：

 Toast.makeText(MainActivity.this,"false",Toast.LENGTH_LONG).show();
在后面加上.show()才会显示。

（二）if判断id是否相同

if(R.id.rb2==checkedId)
                {
                    Toast.makeText(MainActivity.this,"true",Toast.LENGTH_LONG).show();
                }
                else{
                    Toast.makeText(MainActivity.this,"false",Toast.LENGTH_LONG).show();
                }

（三）if判断对象是否相同

RadioButton r=(RadioButton)findViewById(checkedId);
                if(rb2.equals(r))
                {
                    Toast.makeText(MainActivity.this,"true",Toast.LENGTH_LONG).show();
                }
                else{
                    Toast.makeText(MainActivity.this,"false",Toast.LENGTH_LONG).show();
                }