package net.thomasmanthey.touchdelegateexample;

import android.app.Activity;
import android.graphics.Rect;
import android.os.Bundle;
import android.view.TouchDelegate;
import android.view.View;
import android.widget.Toast;

/**
 * This class demonstrates how to use a TouchDelegate to
 * expand the touchable ClickArea of a View within its parent View.
 * The example is quite simple, a Button sits centered in a Fullscreen Linear Layout
 * and gets some extra space to receive TouchEvents
 *
 * All code is licensed under Creative Commons License CC BY 3.0.
 *
 * @author Thomas Manthey
 *
 */
public class TouchDelegateExampleActivity extends Activity {
   
    //The View that delegates its touch events to the delegate
    View parent;
   
    //The Delegate that responds to touch events
    View delegateButton;
   
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
       
        //Get references to the View in the layout
        parent = (View) findViewById(R.id.parent);
        delegateButton = (View) findViewById(R.id.cmdClickMe);
       
         //The TouchDelegate has to be set after everything has been calculated and drawn
        parent.post(getTouchDelegateAction(parent, delegateButton, 50,50,50,50));
    }
   
    /**
     * Adds a touchable padding around a View by constructing a TouchDelegate
     * and adding it to parent View.
     * @param parent The "outer" parent View
     * @param delegate The delegate that handles the TouchEvents
     * @param topPadding Additional touch area in pixels above View
     * @param bootomPadding Additional touch area in pixels below View
     * @param topPadding Additional touch area in pixels left to View
     * @param topPadding Additional touch area in pixels right to View
     * @return A runnable that you can post as action to a Views event queue
     */
    private static Runnable getTouchDelegateAction(final View parent, final View delegate, final int topPadding, final int bottomPadding, final int leftPadding, final int rightPadding) {
        return new Runnable() {
            @Override
            public void run() {
               
                //Construct a new Rectangle and let the Delegate set its values
                Rect touchRect = new Rect();
                delegate.getHitRect(touchRect);
               
                //Modify the dimensions of the Rectangle
                //Padding values below zero are replaced by zeros
                touchRect.top-=Math.max(0, topPadding);
                touchRect.bottom+=Math.max(0, bottomPadding);
                touchRect.left-=Math.max(0, leftPadding);
                touchRect.right+=Math.max(0, rightPadding);
               
                //Now we are going to construct the TouchDelegate
                TouchDelegate touchDelegate = new TouchDelegate(touchRect, delegate);
               
                //And set it on the parent
                parent.setTouchDelegate(touchDelegate);
               
            }
        };
    }
   
    /**
     * Just to show that we hit the target.
     * @param target
     */
    public void cmdClickMe_OnClick(View target) {
        Toast.makeText(this, "You clicked me. Go and save the cheerleader or do something more sensible.",Toast.LENGTH_SHORT).show();
    }
}