Android – Using TouchDelegate

      TouchDelegates in Android allow to increase the touch area of a View, e.g. Button. This is very useful if you want to make it easier for the user to touch your button.

      Here is a small example for the usage of a touch delegate. The layout has the ID root and contains a button with the ID delegated_button.

      

kage de.vogella.android.touchdelegate; import android.app.Activity;import android.graphics.Rect;import android.os.Bundle;import android.view.TouchDelegate;import android.view.View;import android.widget.Button; public class MainActivity extends Activity {    private Button mButton;     /** Called when the activity is first created. */    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.main);        mButton = (Button) findViewById(R.id.delegated_button);        View parent = findViewById(R.id.root);        parent.post(new Runnable() {            public void run() {                // Post in the parent's message queue to make sure the parent                // lays out its children before we call getHitRect()                Rect delegateArea = new Rect();                Button delegate = mButton;                delegate.getHitRect(delegateArea);                delegateArea.top -= 600;                delegateArea.bottom += 600;                delegateArea.left -= 600;                delegateArea.right += 600;                TouchDelegate expandedArea = new TouchDelegate(delegateArea,                        delegate);                // give the delegate to an ancestor of the view we're                // delegating the                // area to                if (View.class.isInstance(delegate.getParent())) {                    ((View) delegate.getParent())                            .setTouchDelegate(expandedArea);                }            };        });    }