Android控件-单选按钮RadioButton

RadioGroup单选按钮用法,还是先看效果图

先中后，点RadioGroup测试按钮，可在标题栏显示选择结果，点清除可以清除选择。
下面上代码，main.xml:

<RadioGroup
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    android:checkedButton="@+id/b1"
    android:id="@+id/RG">
<!--默认选中b1-->
    <RadioButton
        android:text="1"
        android:id="@+id/b1"
    />
     <RadioButton
        android:text="2"
        android:id="@+id/b2"
    />
     <RadioButton
        android:text="3"
        android:id="@+id/b3"
    />
</RadioGroup>
<Button
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:id="@+id/show"
    android:text="RadioGroup测试"
/>
<Button
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:id="@+id/clear"
    android:text="清除"
/>

程序代码:

package com.pocketdigi;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.RadioButton;
import android.widget.RadioGroup;

public class main extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setTitle("RadioGroup测试");
        setContentView(R.layout.main);
        RGDemo();
    }
    RadioGroup rg;
    RadioButton b1;
    RadioButton b2;
    RadioButton b3;
    public void RGDemo(){
        rg=(RadioGroup)findViewById(R.id.RG);
        b1=(RadioButton)findViewById(R.id.b1);
        b2=(RadioButton)findViewById(R.id.b2);
        b3=(RadioButton)findViewById(R.id.b3);
        Button clr=(Button)findViewById(R.id.clear);
        clr.setOnClickListener(clear);
        Button echo=(Button)findViewById(R.id.show);
        echo.setOnClickListener(show);
    }
    private Button.OnClickListener clear=new OnClickListener(){

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            rg.clearCheck();
            setTitle("RadioGroup测试");
        }

    };
    private OnClickListener show=new OnClickListener(){

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            if(b1.isChecked()){
                setTitle("1");
            }
            if(b2.isChecked()){
                setTitle("2");
            }
            if(b3.isChecked()){
                setTitle("3");
            }
        }

    };
}

RadioGroup有一个onCheckChangeListener监听器,可以通过监听器的onCheckedChanged方法捕捉到点击事件，onCheckedChanged方法会传入一个int型的checkedId,可以通过对比传入的checkedId和RadioButton的ID，来确定被点中的选项.

rg.setOnCheckedChangeListener(new OnCheckedChangeListener(){

            @Override
            public void onCheckedChanged(RadioGroup group, int checkedId) {
                // TODO Auto-generated method stub
                if(checkedId==b1.getId()){
                    Toast.makeText(main.this,"b1选中", Toast.LENGTH_LONG).show();
                }
                if(checkedId==b2.getId()){
                    Toast.makeText(main.this,"b2选中", Toast.LENGTH_LONG).show();
                }
                if(checkedId==b3.getId()){
                    Toast.makeText(main.this,"b3选中", Toast.LENGTH_LONG).show();
                }

            }

        });