Question

我有一张图像，我想在Long Press上移动并将图像放在拖动位置。有人告诉我用手势检测来做这件事，但我找不到合适的例子来理解它。通过一个详细的例子帮助我理解这一点。在此先感谢!!!

Answer 1

所以，这是方法如何拖动视图

public boolean onTouch(View view, MotionEvent event) {
final int X = (int) event.getRawX();
final int Y = (int) event.getRawY();
switch (event.getAction() & MotionEvent.ACTION_MASK) {
    case MotionEvent.ACTION_DOWN:
        RelativeLayout.LayoutParams lParams = (RelativeLayout.LayoutParams) view.getLayoutParams();
        _xDelta = X - lParams.leftMargin;
        _yDelta = Y - lParams.topMargin;
        break;
    case MotionEvent.ACTION_UP:
        break;
    case MotionEvent.ACTION_POINTER_DOWN:
        break;
    case MotionEvent.ACTION_POINTER_UP:
        break;
    case MotionEvent.ACTION_MOVE:
        RelativeLayout.LayoutParams layoutParams = (RelativeLayout.LayoutParams) view.getLayoutParams();
        layoutParams.leftMargin = X - _xDelta;
        layoutParams.topMargin = Y - _yDelta;
        layoutParams.rightMargin = -250;
        layoutParams.bottomMargin = -250;
        view.setLayoutParams(layoutParams);
        break;
}
_root.invalidate();
return true;
}}

涉及onTouchListener。另外我认为，你需要在onLongClickListener上设置View的状态（像布尔一样＃34; isMoving＆＃34;）然后用onTouch移动它（if (isMoving)...）

更新

这是我在我的应用中的表现

float x;
float y;
View.OnTouchListener onTouchListener = new View.OnTouchListener() {
    @SuppressWarnings("ResourceType")
    @Override
    public boolean onTouch(View view, MotionEvent event) {
        Point point = (Point) view;
        if (point.isEditind()) {
            if (!point.isEditind()) return false;

            RelativeLayout.LayoutParams params = (RelativeLayout.LayoutParams) point.getLayoutParams();
            //if (view.getId() != R.id.layout_counter) return false;
            switch (event.getAction()) {
                case MotionEvent.ACTION_MOVE:
                    params.topMargin = (int) ((int) -y + event.getRawY() - point.getHeight() - f);
                    params.leftMargin = (int) ((int) -x + event.getRawX() - (point.getWidth() / 2));
                    point.setXY(params.leftMargin,params.topMargin);
                    params.rightMargin = -250;
                    params.bottomMargin =  -250;
                    point.setLayoutParams(params);
                    point.notifyLines();
                    break;

                case MotionEvent.ACTION_UP:
                    params.topMargin = (int) ((int) event.getRawY() - point.getHeight() - f);
                    params.leftMargin = (int) event.getRawX() - (point.getWidth() / 2);
                    point.setXY(params.leftMargin,params.topMargin);
                    params.rightMargin = -250;
                    params.bottomMargin =  -250;
                    view.setLayoutParams(params);
                    point.notifyLines();
                    point.setEditing(false);
                    undoStack.push(((MoveAction)undoStack.pop()).setEndCords(params.leftMargin,params.topMargin));
                    break;

                case MotionEvent.ACTION_DOWN:
                    x = event.getRawX() - point.getLeft();
                    y = event.getRawY() - point.getTop();
                    point.setXY(params.leftMargin,params.topMargin);
                    Log.d(TAG, "onTouch: xD:" + x + " yD:"+ y );
                    point.setLayoutParams(params);
                    point.notifyLines();
                    break;
            }

            return true;
        }
        else return false;
    }
};


    View.OnLongClickListener longClickListener = new View.OnLongClickListener() {
    @Override
    public boolean onLongClick(View view) {
        Log.d(TAG, "onLongClick: ");
        Point point = (Point) view;
        if (!point.isSelected())
        {
            point.setEditing(true);
            undoStack.push(new MoveAction(MainActivity.this,point).setStartCords(point.getLeft(),(int)point.getTop()));

        }
        return true;
    }
};

如何在Android中使用手势检测拖动图像？

1 个答案:

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