Android编程实现GridView控件点击图片变暗效果的方法

@Overridepublic void onCreate(Bundle savedInstanceState) {  super.onCreate(savedInstanceState);  setContentView(R.layout.activity_main);  grid = (GridView) findViewById(R.id.grid);  grid.setAdapter(new GridAdapter());  grid.setOnItemClickListener(new OnItemClickListener() {    @Override    public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,        long arg3) {      Toast.makeText(MainActivity.this, "ddd", 1000).show();    }  });}class GridAdapter extends BaseAdapter {  @Override  public int getCount() {    return imgs.length;  }  @Override  public Object getItem(int arg0) {    return arg0;  }  @Override  public long getItemId(int arg0) {    return arg0;  }  @Override  public View getView(int arg0, View view, ViewGroup arg2) {    if (view == null) {      holder = new ViewHolder();      view = LayoutInflater.from(MainActivity.this).inflate(          R.layout.imgs, null);      holder.view = (ImageView) view.findViewById(R.id.gridimg);      view.setTag(holder);    } else {      holder = (ViewHolder) view.getTag();    }    holder.view.setImageResource(imgs[arg0]);    holder.view.setOnTouchListener(onTouchListener);    return view;  }  class ViewHolder {    ImageView view;  }  public OnTouchListener onTouchListener = new View.OnTouchListener() {    @Override    public boolean onTouch(View view, MotionEvent event) {      switch (event.getAction()) {      case MotionEvent.ACTION_UP:        changeLight((ImageView) view, 0);        // onclick        break;      case MotionEvent.ACTION_DOWN:        changeLight((ImageView) view, -80);        break;      case MotionEvent.ACTION_MOVE:        // changeLight(view, 0);        break;      case MotionEvent.ACTION_CANCEL:        changeLight((ImageView) view, 0);        break;      default:        break;      }      return true;    }  };}private void changeLight(ImageView imageview, int brightness) {  ColorMatrix matrix = new ColorMatrix();  matrix.set(new float[] { 1, 0, 0, 0, brightness, 0, 1, 0, 0,      brightness, 0, 0, 1, 0, brightness, 0, 0, 0, 1, 0 });  imageview.setColorFilter(new ColorMatrixColorFilter(matrix));}