在moveToDest方法里面判断手势回调时增加当前状态的判断，如果当前是open状态，则继续重复右滑就不在回调，反之亦然。

public void moveToDest(final boolean toRight) {
        final Handler handler = new Handler() {
            @Override
            public void handleMessage(Message msg) {
                if (msg.what == 1) {
                    listener.open();
                } else {
                    listener.close();
                }
            }
        };
        new Thread(new Runnable() {
            @Override
            public void run() {
                if (toRight) {
                    while (frontRect_left <= max_left) {
                        alpha = (int) (255 * (float) frontRect_left / (float) max_left);
                        invalidateView();
                        frontRect_left += 3;
                        try {
                            Thread.sleep(3);
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }
                    }
                    alpha = 255;
                    frontRect_left = max_left;
                    if (!isOpen) {
                        isOpen = true;
                        if (listener != null)
                            handler.sendEmptyMessage(1);
                        frontRect_left_begin = max_left;
                    }
                } else {
                    while (frontRect_left >= min_left) {
                        alpha = (int) (255 * (float) frontRect_left / (float) max_left);
                        invalidateView();
                        frontRect_left -= 3;
                        try {
                            Thread.sleep(3);
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }
                    }
                    alpha = 0;
                    frontRect_left = min_left;
                    if (isOpen) {
                        isOpen = false;
                        if (listener != null)
                            handler.sendEmptyMessage(0);
                        frontRect_left_begin = min_left;
                    }
                }
            }
        }).start();
    }

Hi, thank you for sharing this widget, I really liked it. I was using it and making some particular adaptations when I encountered an issue. If I use the widget inside a ScrollView, starting the move to any side and then moving down or up, the ScrollView intercepts the MotionEvent and the switch stops the animation in the middle.

I found a solution and I want to share with you. When ScrollView handle the event, its children Views triggers the MotionEvent ACTION_CANCEL. So I copied the code inside inside ACTION_UP (line 188) and added another case ACTION_CANCEL, like this:

       <rest of code> ...

            break;
        case MotionEvent.ACTION_MOVE:
            eventMovingY = (int) event.getY();
            diffY = eventMovingY - eventStartY;

            eventLastX = (int) event.getRawX();
            diffX = eventLastX - eventStartX;
            int tempX = diffX + frontRect_left_begin;
            tempX = (tempX > max_left ? max_left : tempX);
            tempX = (tempX < min_left ? min_left : tempX);
            if (tempX >= min_left && tempX <= max_left) {
                frontRect_left = tempX;
                alpha = (int) (255 * (float) tempX / (float) max_left);
                invalidateView();
            }

            break;
        case MotionEvent.ACTION_UP:
            moveToDest(isToRight(event));
            break;
        case MotionEvent.ACTION_CANCEL:
            moveToDest(isToRight(event));
            break;
        default:
            break;
    }

private boolean isToRight(MotionEvent event) {
    int wholeX = (int) (event.getRawX() - eventStartX);
    frontRect_left_begin = frontRect_left;
    boolean toRight;
    toRight = (frontRect_left_begin > max_left / 2 ? true : false);
    if (Math.abs(wholeX) < 3) {
        toRight = !toRight;
    }
    return toRight;
}

I'm sorry for my english and thank you again!

When you set RIM_SIZE larger, you will find it obviously.

The radius of the background rounded rectangle maybe not big enough.

I found this problem due to this code in onDraw method:

radius = backRect.height() / 2 - RIM_SIZE;

Maybe you should remove the RIM_SIZE.

OOM exception -> drag the slider one way, then back again. The app will crash. I can reproduce this 100%. Commenting out line 205 moveToDest(toRight) stops the OOM. However leaves the functionality undesirable as the thumb can be left in whatever position you left it in.

The percentage offset attribute allows the user control of the slider switch to be drawn as a percentage of the overall control.

The valid values for this attribute are floats greater than 0 and less than 1.