12.4 单选按钮

o 单选按钮（RadioButton）的基本概念

o RadioGroup与RadioButton

o OnClickListener与OnCheckChangeListener监听器

 

 示例代码：

fragment_main.xml

<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:paddingTop="@dimen/activity_vertical_margin"     tools:context="com.pmplife.radiobutton.MainActivity$PlaceholderFragment" >       <RadioGroup         android:id="@+id/radioGroupId"         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:orientation="horizontal">                 <RadioButton             android:id="@+id/femaleButtonId"             android:layout_width="wrap_content"             android:layout_height="wrap_content"             android:text="female"/>                 <RadioButton             android:id="@+id/maleButtonId"             android:layout_width="wrap_content"             android:layout_height="wrap_content"             android:text="male"/>            </RadioGroup>   </LinearLayout>

 

MainActivity.java

package com.pmplife.radiobutton;   import android.support.v7.app.ActionBarActivity; import android.support.v4.app.Fragment; import android.os.Bundle; import android.view.LayoutInflater; import android.view.Menu; import android.view.MenuItem; import android.view.View; import android.view.ViewGroup; import android.widget.RadioButton; import android.widget.RadioGroup; import android.widget.RadioGroup.OnCheckedChangeListener;   public class MainActivity extends ActionBarActivity {            private RadioGroup radioGroup;          private RadioButton femaleButton;          private RadioButton maleButton;          @Override          protected void onCreate(Bundle savedInstanceState) {                    super.onCreate(savedInstanceState);                    //setContentView(R.layout.activity_main);                    setContentView(R.layout.fragment_main);                      /*if (savedInstanceState == null) {                             getSupportFragmentManager().beginTransaction()                                                .add(R.id.container, new PlaceholderFragment()).commit();                    }*/                                                          //获取代表控制的对象                    radioGroup = (RadioGroup)findViewById(R.id.radioGroupId);                    femaleButton = (RadioButton)findViewById(R.id.femaleButtonId);                    maleButton = (RadioButton)findViewById(R.id.maleButtonId);                                       System.out.println("Test1...");               System.out.println(radioGroup);               System.out.println("Test2...");                            //生成监听器对象                 RadioGroupListener listener = new RadioGroupListener();                 //为控件绑定监听对象                 radioGroup.setOnCheckedChangeListener(listener);          }                   //定义一个类，实现监听器接口          class RadioGroupListener implements OnCheckedChangeListener{                    @Override                    public void onCheckedChanged(RadioGroup group, int checkedId) {                             System.out.println("Test3...");                              if(checkedId == femaleButton.getId()){                                      System.out.print("选中了femaleButton");                             }                             else if(checkedId == maleButton.getId()){                                      System.out.print("选中了maleButton");                             }                                             }          }            @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 onOptionsItemSelected(MenuItem item) {                    // Handle action bar item clicks here. The action bar will                    // automatically handle clicks on the Home/Up button, so long                    // as you specify a parent activity in AndroidManifest.xml.                    int id = item.getItemId();                    if (id == R.id.action_settings) {                             return true;                    }                    return super.onOptionsItemSelected(item);          }            /**           * A placeholder fragment containing a simple view.           */          public static class PlaceholderFragment extends Fragment {                      public PlaceholderFragment() {                    }                      @Override                    public View onCreateView(LayoutInflater inflater, ViewGroup container,                                      Bundle savedInstanceState) {                             View rootView = inflater.inflate(R.layout.fragment_main, container,                                                false);                             return rootView;                    }          }   }