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    }   }; }