android - Android GridView 多选

Question

我想用 GridView 布局做一个活动。我将能够在gridview的元素上拖动手指来多选项目（例如Ruzzle）。当我举起手指时，我必须显示我选择了多少项目。

Answer 1

我知道这是一个老问题，但最近我们遇到了同样的问题，我们想出了一些办法。

假设您要将单元格的颜色更改为绿色。您只需要调用GridView.setOnTouchListener并实现OnTouchListener类似于以下内容：

...
private final int SELECTED_CELL_COLOR = Color.GREEN;
private int mPosition = GridView.INVALID_POSITION;
private boolean mSelecting = false;
...
@Override
public boolean onTouch(View v, MotionEvent event) {
    int action = event.getActionMasked();
    switch (action){
    case MotionEvent.ACTION_DOWN:
    case MotionEvent.ACTION_MOVE:
    case MotionEvent.ACTION_UP:
        int x = (int)event.getX();
        int y = (int)event.getY();
        GridView grid = (GridView)v;
        int position = grid.pointToPosition(x, y);
        if(position != GridView.INVALID_POSITION) {
            v.getParent().requestDisallowInterceptTouchEvent(true); //Prevent parent from stealing the event
            View cellView = (View)grid.getItemAtPosition(position);
            switch (action){
            case MotionEvent.ACTION_DOWN:
                mSelecting = true;
                mPosition = position;
                cellView.setBackgroundColor(SELECTED_CELL_COLOR);
                break;
            case MotionEvent.ACTION_MOVE:
                if (mPosition != position) {
                    mPosition = position;
                    cellView.setBackgroundColor(SELECTED_CELL_COLOR);
                } else {
                    //Repeated cell, noop
                }
                break;
            case MotionEvent.ACTION_UP:
                mSelecting = false;
                mPosition = GridView.INVALID_POSITION;
                //Here you could call a listener, show a dialog or similar
                break;
            }
        }else{
            if(mSelecting){
                mSelecting = false;
            }
        }
    break;
    case MotionEvent.ACTION_CANCEL:
        mSelecting = false;
        break;
    }
    return true;
}