Android:RadioGroup,RadioButton

RadioGroup：如果需要实现一组可选项中选择一个，可以使用该控件来实现；

RadioButton：继承自CompoundButton,是一个单选按钮；

学习如何使用RadioGroup实现选中，获取选中项：

效果：

源代码：

reslayoutactivity_main.xml

<RelativeLayout 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:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <RadioGroup
        android:id="@+id/radioGroupCategory"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_marginLeft="27dp" >

        <RadioButton
            android:id="@+id/radioAndroid"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:checked="true"
            android:text="Android" />

        <RadioButton
            android:id="@+id/radioSpringMVC"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="SpringMVC" />

        <RadioButton
            android:id="@+id/radioStruts"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Struts" />
        
        <RadioButton
            android:id="@+id/radioHibernate"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Hibernate" />
    </RadioGroup>

    <TextView
        android:id="@+id/tvChoiceRadio"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_below="@+id/radioGroupCategory"
        android:layout_marginLeft="27dp"
        android:text="" />

</RelativeLayout>

MainActivity.java

package com.example.helloword;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.DialogInterface.OnClickListener;
import android.os.Bundle;
import android.renderscript.Script.KernelID;
import android.util.Log;
import android.view.KeyEvent;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.TextView;

public class MainActivity extends Activity {
    private RadioGroup radioGroupCategory;
    private RadioButton radioAndroid, radioSpringMVC, radioStruts,
            radioHibernate;
    private TextView tvChoiceRadio;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        this.tvChoiceRadio = (TextView) this.findViewById(R.id.tvChoiceRadio);
        this.radioGroupCategory = (RadioGroup) this
                .findViewById(R.id.radioGroupCategory);

        this.radioAndroid = (RadioButton) this.findViewById(R.id.radioAndroid);
        this.radioSpringMVC = (RadioButton) this
                .findViewById(R.id.radioSpringMVC);
        this.radioStruts = (RadioButton) this.findViewById(R.id.radioStruts);
        this.radioHibernate = (RadioButton) this
                .findViewById(R.id.radioHibernate);

        this.radioStruts.setChecked(true);

        this.radioGroupCategory
                .setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
                    @Override
                    public void onCheckedChanged(RadioGroup radioGroup,
                            int checkedRadioId) {
                        Log.i("test", "onCheckedChanged event fired..."
                                + checkedRadioId);
                        Log.i("test", "Android" + R.id.radioAndroid);
                        Log.i("test", "SpringMVC" + R.id.radioSpringMVC);
                        Log.i("test", "Struts" + R.id.radioStruts);
                        Log.i("test", "Hibernate" + R.id.radioHibernate);

                        switch (checkedRadioId) {
                        case R.id.radioAndroid:
                            tvChoiceRadio.setText("checked value is Android");
                            break;
                        case R.id.radioSpringMVC:
                            tvChoiceRadio.setText("checked value is SpringMVC");
                            break;
                        case R.id.radioStruts:
                            tvChoiceRadio.setText("checked value is Struts");
                            break;
                        case R.id.radioHibernate:
                            tvChoiceRadio.setText("checked value is Hibernate");
                            break;
                        default:
                            tvChoiceRadio.setText("please choice...");
                            break;
                        }

//                        if (radioAndroid.isChecked()) {
//                            tvChoiceRadio.setText("..checked value is Android");
//                        } else if (radioSpringMVC.isChecked()) {
//                            tvChoiceRadio
//                                    .setText("..checked value is SpringMVC");
//                        } else if (radioStruts.isChecked()) {
//                            tvChoiceRadio.setText("..checked value is Struts");
//                        } else if (radioHibernate.isChecked()) {
//                            tvChoiceRadio
//                                    .setText("..checked value is Hibernate");
//                        }
                    }
                });

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onKeyUp(int keyCode, KeyEvent event) {
        // 当点击回退时，弹出该窗口（也就相当于关闭操作）
        if (keyCode == KeyEvent.KEYCODE_BACK) {
            new AlertDialog.Builder(this).setTitle("是否退出？")
                    .setPositiveButton("确定", new OnClickListener() {
                        @Override
                        public void onClick(DialogInterface arg0, int arg1) {
                            finish();
                        }
                    }).setNegativeButton("取消", null).show();
            return true;
        }
        return super.onKeyUp(keyCode, event);
    }
}