我仅在需要时才允许我的视图寻呼机向左滑动

Question

你好，亲爱的观众。

我的情况：

我有一个viewpager，可让我的用户左右滑动。我有一个屏幕（一个片段），我想由用户完成才能刷卡。

我做了什么：

我自定义了viewpager以在希望锁定时锁定滑动（请参见我的代码），但是它同时禁用了两个方向。

理想情况下，我只想禁用从左向右滑动：我希望用户可以向后滑动（从右向左）。我只是想禁用向前滑动（从左到右）。

[我试图在我的视图寻呼机上实现一个onTouchListener来检测滑动方向，但仅在ViewPager解锁时才有效。

你能帮我吗？

编辑1：我还尝试过将onTouchListener放在viewpager的父布局上，但未检测到任何东西。

代码：

 /**
 *   Class "LockableViewPager" :
 *   Custom viewpager that allows or not to swipe between fragments.
 **/
 class LockableViewPager : ViewPager {
    constructor(context: Context, attributeSet: AttributeSet) : super(context, attributeSet)


    companion object {
        private const val TAG = "LockableViewPager"
    }

    /**
     * Is swiping enabled ?
     */
    private var swipeEnabled = true


    /**
     * Intercept all touch screen motion events.
     * Allows to watch events as they are dispatched, and
     * take ownership of the current gesture at any point.
     * 
     * @param event : The motion event being dispatched down the hierarchy.
     * @return Return true to steal motion events from the children and have
     * them dispatched to this ViewGroup through onTouchEvent().
     * The current target will receive an ACTION_CANCEL event, and no further
     * messages will be delivered here.
     */
    override fun onTouchEvent(event: MotionEvent): Boolean {
        return when (swipeEnabled) {
            true -> super.onTouchEvent(event)
            false -> //  Do nothing.
                return false
        }
    }


    /**
     * Implement this method to intercept all touch screen motion events.  This
     * allows you to watch events as they are dispatched to your children, and
     * take ownership of the current gesture at any point.
     *
     * @param event : The motion event being dispatched down the hierarchy.
     * @return Return true to steal motion events from the children and have
     * them dispatched to this ViewGroup through onTouchEvent().
     * The current target will receive an ACTION_CANCEL event, and no further
     * messages will be delivered here.
     */
    override fun onInterceptTouchEvent(event: MotionEvent): Boolean {
        return when (swipeEnabled) {
            true -> super.onInterceptTouchEvent(event)
            false -> swipeEnabled
        }
    }

    /**
     *  Sets the swipeEnabled value to lock or unlock swiping
     */
    fun setSwipeEnabled(swipeEnabled: Boolean) {
        this.swipeEnabled = swipeEnabled
    }    
}

Answer 1

解决方案是使用physics的NeverScrollableScrollPhysics()