ViewPager滑动灵敏度调整

2024年1月23日 290次阅读 来源: Android

ViewPager 手指滑动切换时会不灵敏，我们查看ViewPager源码，切换的判断是由mFlingDistance和mMinimumVelocity决定的。

 private int determineTargetPage(int currentPage, float pageOffset, int velocity, int deltaX) {
        int targetPage;
        if (Math.abs(deltaX) > mFlingDistance && Math.abs(velocity) > mMinimumVelocity) {
            targetPage = velocity > 0 ? currentPage : currentPage + 1;
        } else {
            final float truncator = currentPage >= mCurItem ? 0.4f : 0.6f;
            targetPage = currentPage + (int) (pageOffset + truncator);
        }
        ......

而mFlingDistance和mMinimumVelocity是类内部计算的，并没有公开接口提供设置。

    private static final int MIN_DISTANCE_FOR_FLING = 25; // dips
    
    private static final int MIN_FLING_VELOCITY = 400; // dips
        

   void initViewPager() {
    
        mMinimumVelocity = (int) (MIN_FLING_VELOCITY * density);

        mFlingDistance = (int) (MIN_DISTANCE_FOR_FLING * density
   }

我们可以通过反射来调整这2个值，解决滑动灵敏度的问题

        val mFlingDistance: Field
        mFlingDistance = ViewPager::class.java.getDeclaredField("mFlingDistance")
        mFlingDistance.setAccessible(true)
        val distance = mFlingDistance.get(mViewPager)//获取值
        mFlingDistance.set(mViewPager, 10) //你定义的值

        val mMinimumVelocity: Field
        mMinimumVelocity = ViewPager::class.java.getDeclaredField("mFlingDistance")
        mMinimumVelocity.setAccessible(true)
        val velocity = mMinimumVelocity.get(mViewPager)//获取值
        mMinimumVelocity.set(mViewPager, 5)//你定义的值
    原文作者：Android
    原文地址: https://www.jianshu.com/p/5d26ff3955f5
    本文转自网络文章，转载此文章仅为分享知识，如有侵权，请联系博主进行删除。
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