ImageView点击可变暗的实例代码(android代码技巧)

import android.content.Context;
import android.graphics.ColorMatrixColorFilter;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.widget.ImageView;
public class MyImageView extends ImageView{
  public MyImageView(Context context, AttributeSet attrs) {
    super(context, attrs);
    // TODO Auto-generated constructor stub
    this.setOnTouchListener(VIEW_TOUCH_DARK);
  }
  public static final OnTouchListener VIEW_TOUCH_DARK = new OnTouchListener() { 
    //变暗(三个-50，值越大则效果越深)
    public final float[] BT_SELECTED_DARK = new float[] { 1, 0, 0, 0, -50, 0, 1, 
        0, 0, -50, 0, 0, 1, 0, -50, 0, 0, 0, 1, 0 };
    /*
    //变亮
    public final float[] BT_SELECTED_LIGHT = new float[] { 1, 0, 0, 0, 50, 0, 1, 
        0, 0, 50, 0, 0, 1, 0, 50, 0, 0, 0, 1, 0 };
    //恢复
    public final float[] BT_NOT_SELECTED = new float[] { 1, 0, 0, 0, 0, 0, 
        1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0 }; 
     */
    @Override 
    public boolean onTouch(View v, MotionEvent event) { 
      if (event.getAction() == MotionEvent.ACTION_DOWN) {
        ImageView iv = (ImageView) v; 
        iv.setColorFilter(new ColorMatrixColorFilter(BT_SELECTED_DARK));
      } else if (event.getAction() == MotionEvent.ACTION_UP) {
        ImageView iv = (ImageView) v; 
        iv.clearColorFilter();
      } 
      return false; //如为false，执行ACTION_DOWN后不再往下执行
    } 
  }; 
}