拖放按钮？

Question

我想只在Y方向拖放一个按钮。我实现了这个功能。但它跨越屏幕边界并消失了。请帮助我实现目标。

这是我的代码

    public  class ChoiceTouchListener implements View.OnTouchListener{

    @Override
    public boolean onTouch(View view, MotionEvent motionEvent) {

        int x = (int) motionEvent.getRawX();
        int y = (int) motionEvent.getRawY();
        DisplayMetrics metrics = getResources().getDisplayMetrics();


        switch (motionEvent.getAction() & MotionEvent.ACTION_MASK){
            case MotionEvent.ACTION_DOWN:
                RelativeLayout.LayoutParams tparams = (RelativeLayout.LayoutParams) view.getLayoutParams();
                changey = y- tparams.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 params = (RelativeLayout.LayoutParams) view.getLayoutParams();


                params.topMargin = y-changey;

                view.setLayoutParams(params);
                break;
        }

        rootlayout.invalidate();

        return true;
    }
}

Answer 1

您可以使用它来限制屏幕边界。

int width=cropperLayout.getLayoutParams().width;;
        int height=cropperLayout.getLayoutParams().height;
        switch (event.getAction()) {

            case MotionEvent.ACTION_DOWN:

                dX = v.getX() - event.getRawX();
                dY = v.getY() - event.getRawY();

                return true;

            case MotionEvent.ACTION_MOVE:

                if (width == windowWidth && height == windowHeight){}
                else {
                    v.animate()
                            .x(event.getRawX() + dX)
                            .y(event.getRawY() + dY)
                            .setDuration(0)
                            .start();

                    if (event.getRawX() + dX + width > windowWidth) {
                        v.animate()
                                .x(windowWidth - width)
                                .setDuration(0)
                                .start();
                    }
                    if (event.getRawX() + dX < 0) {
                        v.animate()
                                .x(0)
                                .setDuration(0)
                                .start();
                    }
                    if (event.getRawY() + dY + height > windowHeight) {
                        v.animate()
                                .y(windowHeight - height)
                                .setDuration(0)
                                .start();
                    }
                    if (event.getRawY() + dY < 0) {
                        v.animate()
                                .y(0)
                                .setDuration(0)
                                .start();
                    }

                    return true;
                }