SimpleGestureFilter.java

/* 
 * Copyright 2008-2013, ETH Zürich, Samuel Welten, Michael Kuhn, Tobias Langner,
 * Sandro Affentranger, Lukas Bossard, Michael Grob, Rahul Jain, 
 * Dominic Langenegger, Sonia Mayor Alonso, Roger Odermatt, Tobias Schlueter,
 * Yannick Stucki, Sebastian Wendland, Samuel Zehnder, Samuel Zihlmann,       
 * Samuel Zweifel
 *
 * This file is part of Jukefox.
 *
 * Jukefox is free software: you can redistribute it and/or modify it under the
 * terms of the GNU General Public License as published by the Free Software 
 * Foundation, either version 3 of the License, or any later version. Jukefox is
 * distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
 * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A 
 * PARTICULAR PURPOSE. See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * Jukefox. If not, see <http://www.gnu.org/licenses/>.
 */
package ch.ethz.dcg.pancho3.view.commons;

import android.app.Activity;
import android.view.GestureDetector;
import android.view.GestureDetector.SimpleOnGestureListener;
import android.view.MotionEvent;

/**
 * @author http://misha.beshkin.lv/android-swipe-gesture-implementation/
 */
public class SimpleGestureFilter extends SimpleOnGestureListener {

	public final static int SWIPE_UP = 1;
	public final static int SWIPE_DOWN = 2;
	public final static int SWIPE_LEFT = 3;
	public final static int SWIPE_RIGHT = 4;

	public final static int MODE_TRANSPARENT = 0;
	public final static int MODE_SOLID = 1;
	public final static int MODE_DYNAMIC = 2;

	private final static int ACTION_FAKE = -13; //just an unlikely number
	private int swipe_Min_Distance = 200;
	private int swipe_Max_Distance = Integer.MAX_VALUE; // Was 350
	private int swipe_Min_Velocity = 100;

	private int mode = MODE_DYNAMIC;
	private boolean running = true;
	private boolean tapIndicator = false;

	private Activity context;
	private GestureDetector detector;
	private SimpleGestureListener listener;

	public SimpleGestureFilter(Activity context, SimpleGestureListener sgl) {

		this.context = context;
		this.detector = new GestureDetector(context, this);
		this.listener = sgl;
	}

	public void onTouchEvent(MotionEvent event) {

		if (!this.running) {
			return;
		}

		boolean result = this.detector.onTouchEvent(event);

		if (this.mode == MODE_SOLID) {
			event.setAction(MotionEvent.ACTION_CANCEL);
		} else if (this.mode == MODE_DYNAMIC) {

			if (event.getAction() == ACTION_FAKE) {
				event.setAction(MotionEvent.ACTION_UP);
			} else if (result) {
				event.setAction(MotionEvent.ACTION_CANCEL);
			} else if (this.tapIndicator) {
				event.setAction(MotionEvent.ACTION_DOWN);
				this.tapIndicator = false;
			}

		}
		//else just do nothing, it's Transparent
	}

	public void setMode(int m) {
		this.mode = m;
	}

	public int getMode() {
		return this.mode;
	}

	public void setEnabled(boolean status) {
		this.running = status;
	}

	public void setSwipeMaxDistance(int distance) {
		this.swipe_Max_Distance = distance;
	}

	public void setSwipeMinDistance(int distance) {
		this.swipe_Min_Distance = distance;
	}

	public void setSwipeMinVelocity(int distance) {
		this.swipe_Min_Velocity = distance;
	}

	public int getSwipeMaxDistance() {
		return this.swipe_Max_Distance;
	}

	public int getSwipeMinDistance() {
		return this.swipe_Min_Distance;
	}

	public int getSwipeMinVelocity() {
		return this.swipe_Min_Velocity;
	}

	@Override
	public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
			float velocityY) {

		final float xDistance = Math.abs(e1.getX() - e2.getX());
		final float yDistance = Math.abs(e1.getY() - e2.getY());

		if (xDistance > this.swipe_Max_Distance || yDistance > this.swipe_Max_Distance) {
			return false;
		}

		velocityX = Math.abs(velocityX);
		velocityY = Math.abs(velocityY);
		boolean result = false;

		if (velocityX > this.swipe_Min_Velocity && xDistance > this.swipe_Min_Distance) {
			if (e1.getX() > e2.getX()) {
				this.listener.onSwipe(SWIPE_LEFT);
			} else {
				this.listener.onSwipe(SWIPE_RIGHT);
			}

			result = true;
		}
		else if (velocityY > this.swipe_Min_Velocity && yDistance > this.swipe_Min_Distance) {
			if (e1.getY() > e2.getY()) {
				this.listener.onSwipe(SWIPE_UP);
			} else {
				this.listener.onSwipe(SWIPE_DOWN);
			}

			result = true;
		}

		return result;
	}

	@Override
	public boolean onSingleTapUp(MotionEvent e) {
		this.tapIndicator = true;
		return false;
	}

	@Override
	public boolean onDoubleTap(MotionEvent arg0) {
		this.listener.onDoubleTap();
		return true;
	}

	@Override
	public boolean onDoubleTapEvent(MotionEvent arg0) {
		return true;
	}

	@Override
	public boolean onSingleTapConfirmed(MotionEvent arg0) {

		if (this.mode == MODE_DYNAMIC) { // we owe an ACTION_UP, so we fake an
			arg0.setAction(ACTION_FAKE); //action which will be converted to an ACTION_UP later.
			this.context.dispatchTouchEvent(arg0);
		}

		return false;
	}

	public static interface SimpleGestureListener {

		void onSwipe(int direction);

		void onDoubleTap();
	}

}