Android Radio Button Tutorial

Introduction of Android Radio Button Control

Android provide radio control. It uses radio group feature to bind radio button into single group. So that user can select a single radio button from one group.

How to define radio control

Android use seperate file for layout. This file stored in android res/layout directory.

syntex :

 <android:id="@+id/radioSex"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content">
 <RadioButton
            android:id="@+id/radioMale"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Male" 
            android:checked="true"/>
 <RadioButton
            android:id="@+id/radioFemale"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Female"/>
 <RadioGroup/>

 

Above syntex define following properties

• android:id a unique id provided.
• android:layout_width this property is used to define width.
• android:layout_height this property is used to define height.

Example

1. Make layout file(main.xml) which contains a checkbox. If we check on checkbox it display a message.
   
   

   <?xml version="1.0" encoding="utf-8"?>
   <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
       android:id="@+id/linearLayout1"
       android:layout_width="fill_parent"
       android:layout_height="fill_parent"
       android:orientation="vertical" >
    
    <android:id="@+id/radioSex"
           android:layout_width="wrap_content"
           android:layout_height="wrap_content">
    <RadioButton
               android:id="@+id/radioMale"
               android:layout_width="wrap_content"
               android:layout_height="wrap_content"
               android:text="Male" 
               android:checked="true"/>
    <RadioButton
               android:id="@+id/radioFemale"
               android:layout_width="wrap_content"
               android:layout_height="wrap_content"
               android:text="Female"/>
    <RadioGroup/>
    
    <Button
           android:id="@+id/btnDisplay"
           android:layout_width="wrap_content"
           android:layout_height="wrap_content"
           android:text="show result" />
           
    </LinearLayout>
   

2. Then apply onclick event
   
   

   public class MyAndroidAppActivity extends Activity {
    
       private CheckBox chkandroid;
   	@Override
   	public void onCreate(Bundle savedInstanceState) {
   		super.onCreate(savedInstanceState);
   		setContentView(R.layout.main);
           addListenerOnButton();
   	}
        public void addListenerOnButton() {
    
   	radioSexGroup = (RadioGroup) findViewById(R.id.radioSex);
   	btnDisplay = (Button) findViewById(R.id.btnDisplay);
    
   	btnDisplay.setOnClickListener(new OnClickListener() {
    
   		@Override
   		public void onClick(View v) {
    
   		        // get selected radio button from radioGroup
   			int selectedId = radioSexGroup.getCheckedRadioButtonId();
    
   			// find the radiobutton by returned id
   		        radioSexButton = (RadioButton) findViewById(selectedId);
    
   			Toast.makeText(MyAndroidAppActivity.this,
   				radioSexButton.getText(), Toast.LENGTH_SHORT).show();
    
   		}
    
   	});
    
     }
   }
   
   

3. Output :