Android Open Source - PhotoStrips Custom Horizontal Scroll View

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License

The source code is released under:

MIT License

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Java Source Code

package com.ahmetkizilay.image.photostrips.utils;
//from  w  w w . j a v a2 s .  c  o  m
import android.content.Context;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.widget.HorizontalScrollView;

/***
 * I found this code somewhere on stack overflow and modified it according to my needs.
 * Listens to the end of horizontal scroll view scroll actions and triggers an event 
 * 
 * @author ahmetkizilay
 *
 */
public class CustomHorizontalScrollView extends HorizontalScrollView {
  
  private boolean occupied = false;
  private boolean toBeTriggered = false;
  private ScrollStoppedEvent eventToTrigger;
  
  private Runnable scrollerTask;
  private int initialPosition;

  private int newCheck = 100;
  
  private OnScrollStoppedListener onScrollStoppedListener;

  public final class ScrollStoppedEvent {
    public static final int SCROLL_START = 0;
    public static final int SCROLL_END = 1;

    private int action;

    private ScrollStoppedEvent(int action) {
      this.action = action;
    }

    public int getAction() {
      return this.action;
    }
  }

  public interface OnScrollStoppedListener {
    void onScrollStopped(ScrollStoppedEvent evt);
  }

  public CustomHorizontalScrollView(Context context, AttributeSet attrs) {
    super(context, attrs);

    this.setOnTouchListener(new OnTouchListener() {
      public boolean onTouch(View v, MotionEvent event) {
        

        if (event.getAction() == MotionEvent.ACTION_MOVE) {
          startScrollerTask();
        }
        
        if (event.getAction() == MotionEvent.ACTION_UP) {
          endScrollTask();
        }
        
        
        return false;
      }
    });

    scrollerTask = new Runnable() {

      public void run() {

        int newPosition = getScrollX();
        if (initialPosition - newPosition == 0) {// has stopped

          if (onScrollStoppedListener != null) {

            eventToTrigger = new ScrollStoppedEvent(
                newPosition == 0 ? ScrollStoppedEvent.SCROLL_START
                    : ScrollStoppedEvent.SCROLL_END);
            
            toBeTriggered = true;            
          }
        } else {
          occupied = false;
        }        
      }
    };
  }


  public void endScrollTask() {
    occupied = false;
    if(toBeTriggered) {
      toBeTriggered = false;
      onScrollStoppedListener.onScrollStopped(eventToTrigger);      
    }
  }
  
  public void setOnScrollStoppedListener(
      CustomHorizontalScrollView.OnScrollStoppedListener listener) {
    onScrollStoppedListener = listener;
  }

  public void startScrollerTask() {

    if(!occupied) {
      occupied = true;
      toBeTriggered = false;
      
      initialPosition = getScrollX();
      CustomHorizontalScrollView.this.postDelayed(scrollerTask, newCheck);
    }
  }


}

Java Source Code List