DoubleClickListner.txt

import android.os.SystemClock;
import android.view.View;
import android.view.View.OnClickListener;

/**
 * A simple double-click listener
 * Usage: 
 * 			// Scenario 1: Setting double click listener for myView
 * 			myView.setOnClickListener(new DoubleClickListener() {
 *				
 *				@Override
 *				public void onDoubleClick() {
 *					// double-click code that is executed if the user double-taps
 *					// within a span of 200ms (default).
 *				}
 *			});
 *
 * 			// Scenario 2: Setting double click listener for myView, specifying a custom double-click span time
 * 			myView.setOnClickListener(new DoubleClickListener(500) {
 *				
 *				@Override
 *				public void onDoubleClick() {
 *					// double-click code that is executed if the user double-taps
 *					// within a span of 500ms (default).
 *				}
 *			});
 * 
 */
public abstract class DoubleClickListener implements OnClickListener {
	
	// The time in which the second tap should be done in order to qualify as
	// a double click
	private static final long DEFAULT_QUALIFICATION_SPAN = 200;
	private long doubleClickQualificationSpanInMillis;
	private long timestampLastClick;
	
	public DoubleClickListener() {
		doubleClickQualificationSpanInMillis = DEFAULT_QUALIFICATION_SPAN;
		timestampLastClick = 0;
	}
	
	public DoubleClickListener(long doubleClickQualificationSpanInMillis) {
		this.doubleClickQualificationSpanInMillis = doubleClickQualificationSpanInMillis;
		timestampLastClick = 0;
	}

	@Override
	public void onClick(View v) {
		if((SystemClock.elapsedRealtime() - timestampLastClick) < doubleClickQualificationSpanInMillis) {
			onDoubleClick();
		}
		timestampLastClick = SystemClock.elapsedRealtime();
	}
	
	public abstract void onDoubleClick();

}