docs/html/guide/topics/views/ui-events.jd

page.title=Handling UI Events
@jd:body

<p>Many Android classes declare callback methods for handling relevant UI events such as keypresses, touch events, focus changes, and so on. For example, {@link android.app.Activity Activity} provides the methods onKeyDown() and onKeyUp() and {@link android.widget.TextView TextView} provides onFocusChanged(). </p>

<p>In most cases, you can handle events just by overriding the appropriate handler methods. When an event is received, the Android system calls your handler method with the event data.</p>

<p>However, some classes do not declare handler methods for specific events. For example, {@link android.widget.Button Button} does not declare an onClick() handler method. To handle such events, you need to create an anonymous class to act as a listener for the event, then register the listener with the target class object. The example below shows how to set up a handler for click events in a Button object. </p>



</p>
<pre>public class ExampleSendResult extends Activity
{
    protected void onCreate(Bundle savedValues)
    {
        ...

        // Listen for button clicks.
        Button button = (Button)findViewById(R.id.corky);
        button.setOnClickListener(mCorkyListener);
    }

    // Create an anonymous class to act as a button click listener.
    private OnClickListener mCorkyListener = new OnClickListener()
    {
        public void onClick(View v)
        {
          //handle click event...
        }
    };</pre>