android-Animate隐藏/显示工具栏在选项卡之间滑动时的显示/显示，例如在whatsapp相机中 [英] android-Animate the hiding/showing of toolbar on swiping between tabs like in whatsapp camera

问题描述

在tablayout中的各个选项卡之间滑动时，我成功显示和隐藏了appbar.但现在，我希望为标签的这种隐藏和出现动画化，就像我们在whatsapp中切换相机"标签时所做的那样.

i am successfull in showing and hiding of appbar when swiping between tabs in tablayout. but now i want to animate this hiding and appearing of tab smoothly like we do in switching for the camera tab in whatsapp.

推荐答案

解决方案是使用 onPageScrolled()中的translationY属性来翻译 AppbarLayout 使用 AppbarLayout 的底部值回调 ViewPager 的 OnPageChangeListener 接口.

The way to go about it is to translate the AppbarLayout using its translationY attribute in onPageScrolled() callback of the ViewPager's OnPageChangeListener interface using the AppbarLayout's bottom value.

mViewPager.addOnPageChangeListener(new OnPageChangeListener(){

    @Override
    public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

        //  get an instance of the appBarLayout This should probably be done at the activity level in its oncreate() method
        /*  example:
            public ViewPager mViewPager;
            public AppBarLayout appBar;

            onCreate(...){
                ...
                mViewPager = (ViewPager) findViewById(R.id.viewpager);
                appBar = (AppBarLayout) findViewById(R.id.appbar);

                mViewPager.addOnPageChangeListener(...);
                ...
            }
        */

        // set the position you want the app bar to be hidden on the ViewPager
        int hideAppBarAtPosition = 0;

        if (appBar != null) {

            // get an instance of the bottom value of the appBar
            float mBottom = (float) appBar.getBottom();

            // going right offset changes from zero to one
            if (position == hideAppBarAtPosition) {

                // Translate the appBar up as the resideReveal slides into view
                float y = (positionOffset * mBottom) - mBottom;

                // Raise the appBar a little bit higher when it is no longer visible
                if (y == -mBottom) {
                    float h = (float) appBar.getHeight();
                    if (mBottom < h) mBottom = h;
                    y = -mBottom - mBottom / 8f;
                }

                appBar.setTranslationY(y);

            } else if (position == hideAppBarAtPosition - 1) {

                // Translate the appBar up as the resideReveal slides into view
                appBar.setTranslationY(-(positionOffset * mBottom));

            } else if (appBar.getTranslationY() != 0f) {

                // Reset translation of the appBar
                appBar.setTranslationY(0f);

            }   
        }
    }

    @Override
    public void onPageSelected(int position) {

    }

    @Override
    public void onPageScrollStateChanged(int state) {

    }
});

如果您需要更多有关如何实现它的想法，请查看此开源项目 https://github.com/goody-h/ResidingTab

If you need more ideas on how to implement it, view this open source project https://github.com/goody-h/ResidingTab

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