Android ViewPager-此设计的平滑过渡 [英] Android ViewPager - Smooth Transition for this Design

问题描述

对于以下设计，我无法真正算出数学公式来进行平滑过渡.任何帮助将不胜感激:).

I can't really figure out the math to do smooth transition for the following design. Any help would be greatly appreciated :).

在过渡过程中，页面在上下跳跃，但我希望它们平滑一些.

During transition, the pages are jumping up and down but I would like them to be smooth instead.

设计

过渡

相关的ViewPage代码:

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    final ViewPager viewPager = (ViewPager) findViewById(R.id.pager);
    PagerAdapter pagerAdapter = new PagerAdapter(getSupportFragmentManager());
    viewPager.setAdapter(pagerAdapter);
    viewPager.setOffscreenPageLimit(3);
    viewPager.setPageMargin(100);
    viewPager.setPageTransformer(false, new ViewPager.PageTransformer() {
        @Override
        public void transformPage(View page, float position) {
            int pageWidth = viewPager.getMeasuredWidth() - viewPager.getPaddingLeft() - viewPager.getPaddingRight();
            int pageHeight = viewPager.getHeight();
            int paddingLeft = viewPager.getPaddingLeft();
            float transformPos = (float) (page.getLeft() - (viewPager.getScrollX() + paddingLeft)) / pageWidth;

            final float normalizedposition = Math.abs(Math.abs(transformPos) - 1);
            page.setAlpha(normalizedposition + 0.5f);

            if (transformPos < -1) { // [-Infinity,-1)
                // This page is way off-screen to the left.
                page.setTranslationY(0);
            } else if (transformPos <= 1) { // [-1,1]
                page.setTranslationY(-pageHeight / 10);

            } else { // (1,+Infinity]
                // This page is way off-screen to the right.
                page.setTranslationY(0);
            }


        }
    });

}

注意:"transformPos"用于解决此错误- https ://code.google.com/p/android/issues/detail?id = 64046

Note: 'transformPos' is used to address this bug - https://code.google.com/p/android/issues/detail?id=64046

我的ViewPager

<android.support.v4.view.ViewPager
    android:id="@+id/pager"
    android:layout_width="match_parent"
    android:layout_height="260dp"
    android:layout_centerInParent="true"
    android:clipToPadding="false"
    android:paddingLeft="80dp"
    android:paddingRight="80dp"/>

完整来源- https://github.com/krishnaraj/ViewPagerSample

推荐答案

尝试一下

    viewPager.setPageTransformer(false, new ViewPager.PageTransformer() {
        @Override
        public void transformPage(View page, float position) {
            int pageWidth = viewPager.getMeasuredWidth() - viewPager.getPaddingLeft() - viewPager.getPaddingRight();
            int pageHeight = viewPager.getHeight();
            int paddingLeft = viewPager.getPaddingLeft();
            float transformPos = (float) (page.getLeft() - (viewPager.getScrollX() + paddingLeft)) / pageWidth;

            final float normalizedposition = Math.abs(Math.abs(transformPos) - 1);
            page.setAlpha(normalizedposition + 0.5f);

            int max = -pageHeight / 10;

            if (transformPos < -1) { // [-Infinity,-1)
                // This page is way off-screen to the left.
                page.setTranslationY(0);
            } else if (transformPos <= 1) { // [-1,1]
                page.setTranslationY(max * (1-Math.abs(transformPos)));

            } else { // (1,+Infinity]
                // This page is way off-screen to the right.
                page.setTranslationY(0);
            }


        }
    });

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