Android Open Source - Airplanes Double Tap Detector

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From Project

Back to project page Airplanes.

License

The source code is released under:

GNU General Public License

Java Source Code

package com.axnsan.airplanes.util;
// ww w . j  av a2s .  com
public class DoubleTapDetector implements Detector {
  /**Maximum slop(distance between taps) in pixels**/
  public static final int SLOP = 30;
  /**Max delay between taps in seconds**/
  public static final float DELAY = 0.5f;
  
  private float delta = 0.f;
  private int x, y;
  private boolean waitingFor2ndTap = false;
  private DoubleTapListener listener = null;
  
  public DoubleTapDetector(DoubleTapListener lis) {
    listener = lis;
  }
  
  public void tap(int x, int y) {
    if (waitingFor2ndTap) {
      if (delta <= DELAY && Math.abs(this.x - x) < SLOP && Math.abs(this.y - y) < SLOP) {
        listener.doubleTap(this.x, this.y);
      }
      waitingFor2ndTap = false;
    }
    else {
      waitingFor2ndTap = true;
      this.x = x; this.y = y;
      
      /* We set the initial duration to -1, and only set it to 0 and begin counting in the next frame.
           * This necessary to ensure we don't count the time before this frame.
           * We must do this because rendering only happens when waiting for input,
           * and as such frame delta can be very high if the last input was long ago.*/
      delta = -1.f;
    }
  }
  
  public boolean waiting() {
    return waitingFor2ndTap;
  }
  
  public void elapsed(float delta) {
    if (this.delta < 0.f) 
      this.delta = 0.f; 
    else {
      this.delta += delta;
      if (this.delta > DELAY) /*If we passed the max delay, stop waiting*/
        waitingFor2ndTap = false;
    }
  }
  
};

Java Source Code List

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