安卓初学者 : Touch events in android gridview

Question

我正在使用以下代码来处理 gridview(从 http://developer.android.com/resources/tutorials/views/hello-gridview.html 稍作修改)。我想将 onClicklistener 和 onClick() 方法替换为它们的“触摸”等价物，即 touchlistener 和 onTouch() 以便当我触摸 gridview 中的元素时，该元素的图像会发生变化，并且在同一元素上双击会接受它回到原来的状态。

我该怎么做？我无法让我的代码执行此操作。 clicklistener 在某种程度上起作用，但触摸不起作用。请帮忙。

public class ImageAdapter extends BaseAdapter {
private Context mContext;

public ImageAdapter(Context c) {
    mContext = c;
}

public int getCount() {
    return mThumbIds.length;
}

public Object getItem(int position) {
    return null;
}

public long getItemId(int position) {
    return 0;
}

// create a new ImageView for each item referenced by the Adapter
public View getView(int position, View convertView, ViewGroup parent) {
    ImageView imageView;
    if (convertView == null) {  // if it's not recycled, initialize some attributes
        imageView = new ImageView(mContext);
        imageView.setLayoutParams(new GridView.LayoutParams(85, 85));
        imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
        imageView.setPadding(8, 8, 8, 8);

        imageView.setOnClickListener(new View.OnClickListener()
            {

              @Override
              public void onClick(View view) 
              {

                  if(position==0)
                  {
                                  //do this
                              }
                              else
                              {
                                //do this
                              }
                           }
                    });

    } else {
        imageView = (ImageView) convertView;
    }

    imageView.setImageResource(mThumbIds[position]);
    return imageView;
}

// references to our images
private Integer[] mThumbIds = {
        R.drawable.sample_2, R.drawable.sample_3,
        R.drawable.sample_4, R.drawable.sample_5,
        R.drawable.sample_6, R.drawable.sample_7,
        R.drawable.sample_0, R.drawable.sample_1,
        R.drawable.sample_2, R.drawable.sample_3,
        R.drawable.sample_4, R.drawable.sample_5,
        R.drawable.sample_6, R.drawable.sample_7,
        R.drawable.sample_0, R.drawable.sample_1,
        R.drawable.sample_2, R.drawable.sample_3,
        R.drawable.sample_4, R.drawable.sample_5,
        R.drawable.sample_6, R.drawable.sample_7
};
}

Answer 1

以这种方式使用OnTouchListener。阅读 MotionEvent 类型，例如 ACTION_UP、ACTION_MOVE 和 ACTION_DOWN，这意味着此处按下了键、移动了鼠标或未按下键这里……

public void addListenerToGrid() {
    gridView = (GridView) findViewById(R.id.gridView1);

    gridView.setOnTouchListener(new OnTouchListener() {
        public boolean onTouch(View v, MotionEvent me) {

            int action = me.getActionMasked();
            float currentXPosition = me.getX();
            float currentYPosition = me.getY();
            int position = gridView.pointToPosition((int) currentXPosition, (int) currentYPosition);
                        if (action == MotionEvent.ACTION_UP) {
                            // Key was pressed here
                        }

            return true;