viewpager切换月份天数

viewPager初始化后设置OnPageChangeListener监听
但是手指滑动离开屏幕后，onPageScrollStateChanged的回调经历了1、2，最终没有回调0，这种是什么情况？

```java

06-01 22:35:01.148 16959 16959 D DateView : DateView  
06-01 22:35:01.160 16959 16959 D DateView : onFinishInflate  
06-01 22:35:01.160 16959 16959 D DateView : initView
06-01 22:35:01.163 16959 16959 D DateView : setDate: 2023骞?6鏈?
06-01 22:35:01.166 16959 16959 D DateView : setDate: getDifMonth = 0
06-01 22:35:01.181 16959 16959 D CustomDateView: init: oneHeight = 116.0
06-01 22:35:01.181 16959 16959 D CustomDateView : position: 250
06-01 22:35:01.181 16959 16959 D CustomDateView : setDate: 2023   5
06-01 22:35:01.199 16959 16959 D CustomDateView: init: oneHeight = 116.0
06-01 22:35:01.199 16959 16959 D CustomDateView : position: 249
06-01 22:35:01.199 16959 16959 D CustomDateView : setDate: 2023   4
06-01 22:35:01.213 16959 16959 D CustomDateView: init: oneHeight = 116.0
06-01 22:35:01.213 16959 16959 D CustomDateView : position: 251
06-01 22:35:01.213 16959 16959 D CustomDateView : setDate: 2023   6
06-01 22:35:01.231 16959 16959 D  DateView : onPageScrolled position = 250 , offset = 0.0 , offsetPixels = 0
06-01 22:35:01.233 16959 16959 D  CustomDateView : onDraw
06-01 22:35:01.233 16959 16959 D  CustomDateView : onDraw
06-01 22:35:01.233 16959 16959 D  CustomDateView : onDraw
06-01 22:35:02.876 16959 16959 D  DateView : onPageScrollStateChanged i = 1
06-01 22:35:02.877 16959 16959 D  DateView : onPageScrolled position = 249 , offset = 0.9982143 , offsetPixels = 1118
06-01 22:35:02.896 16959 16959 D  DateView : onPageScrolled position = 249 , offset = 0.9875 , offsetPixels = 1106
06-01 22:35:02.915 16959 16959 D  DateView : onPageScrolled position = 249 , offset = 0.9776786 , offsetPixels = 1095
06-01 22:35:02.933 16959 16959 D  DateView : onPageScrolled position = 249 , offset = 0.9660714 , offsetPixels = 1082
06-01 22:35:02.950 16959 16959 D  DateView : onPageScrolled position = 249 , offset = 0.95535713 , offsetPixels = 1070
06-01 22:35:02.967 16959 16959 D  DateView : onPageScrolled position = 249 , offset = 0.94285715 , offsetPixels = 1056
06-01 22:35:02.987 16959 16959 D  DateView : onPageScrolled position = 249 , offset = 0.9285714 , offsetPixels = 1040
06-01 22:35:03.002 16959 16959 D  DateView : onPageScrolled position = 249 , offset = 0.91339284 , offsetPixels = 1023
06-01 22:35:03.020 16959 16959 D  DateView : onPageScrolled position = 249 , offset = 0.89464283 , offsetPixels = 1002
06-01 22:35:03.038 16959 16959 D  DateView : onPageScrolled position = 249 , offset = 0.875 , offsetPixels = 980
06-01 22:35:03.055 16959 16959 D  DateView : onPageScrolled position = 249 , offset = 0.85535717 , offsetPixels = 958
06-01 22:35:03.072 16959 16959 D  DateView : onPageScrolled position = 249 , offset = 0.8267857 , offsetPixels = 925
06-01 22:35:03.090 16959 16959 D  DateView : onPageScrolled position = 249 , offset = 0.79375 , offsetPixels = 889
06-01 22:35:03.108 16959 16959 D  DateView : onPageScrolled position = 249 , offset = 0.75 , offsetPixels = 840
06-01 22:35:03.125 16959 16959 D  DateView : onPageScrolled position = 249 , offset = 0.69375 , offsetPixels = 777
06-01 22:35:03.143 16959 16959 D  DateView : onPageScrolled position = 249 , offset = 0.62678576 , offsetPixels = 702
06-01 22:35:03.160 16959 16959 D  DateView : onPageScrolled position = 249 , offset = 0.5419643 , offsetPixels = 607
06-01 22:35:03.178 16959 16959 D  DateView : onPageScrolled position = 249 , offset = 0.36071426 , offsetPixels = 403
06-01 22:35:03.178 16959 16959 D  DateView : onPageScrollStateChanged i = 2
06-01 22:35:03.178 16959 16959 D  DateView : onPageSelected position = 249 , lastPosition = 250.0 , getCurrentItem() = 249

```

当用户开始滑动ViewPager时，会触发onPageScrollStateChanged()回调，此时状态为1（表示正在拖动），然后onPageScrolled()方法会被调用多次，其中position参数表示当前页面的索引，offset参数表示当前页面的偏移量，offsetPixels参数表示当前页面的像素偏移量。在用户松开手指时，ViewPager会尝试滚动到最近的页面，并触发一次onPageScrolled()回调，此时position参数表示即将显示的页面的索引，offset和offsetPixels参数为0。

• 你可以看下这个问题的回答https://ask.csdn.net/questions/239455
• 我还给你找了一篇非常好的博客，你可以看看是否有帮助，链接：ViewPager的onPageScrolled回调不完整
• 除此之外, 这篇博客: Android ViewPager控件中的 2. OnPageChangeListener监听器 部分也许能够解决你的问题, 你可以仔细阅读以下内容或跳转源博客中阅读:
  

• OnPageChangeListener有三个方法

  • onPageScrolled(int, float, int)方法，显示滑动时页面状态。

    public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels)
    

    手势从左往右滑动，position为前一页面，positionOffset从1到0。
    手势从右往左滑动，position为当前页面，positionOffset从0到1。

  • onPageSelected(int)方法，position是被选择页面

    public void onPageSelected(int position)
    

  • onPageScrollStateChanged(int)方法，

    public void onPageScrollStateChanged(int state)
    

    state有三种状态

    • SCROLL_STATE_IDLE，静止状态。
    • SCROLL_STATE_DRAGGING，开始拖曳。
    • SCROLL_STATE_SETTLING，停止拖曳。