CollectionFragment.java 文件源码

private void initAppBar() {
    mAppBar.addOnOffsetChangedListener((appBarLayout, verticalOffset) -> {
        int maxScroll = mAppBar.getTotalScrollRange();
        float percentage = (float) Math.abs(verticalOffset) / (float) maxScroll;

        if (percentage == 1f) {
            if (mIsSearchBarShown) {
                mIsSearchBarShown = false;
                mSearchBar.animate().cancel();
                mSearchBar.animate().translationY(-mSearchBarTranslationY)
                        .setInterpolator(new DecelerateInterpolator())
                        .setDuration(400)
                        .start();
            }
        } else if (percentage < 0.8f) {
            if (!mIsSearchBarShown) {
                mIsSearchBarShown = true;
                mSearchBar.animate().cancel();
                mSearchBar.animate().translationY(0)
                        .setInterpolator(new LinearOutSlowInInterpolator())
                        .setDuration(400)
                        .start();
            }
        }

        if (percentage < 0.2f) {
            if (!mIsAppBarExpanded) {
                mIsAppBarExpanded = true;
                int color = ColorHelper.getAttributeColor(getActivity(), R.attr.colorPrimary);
                ColorHelper.setupStatusBarIconColor(getActivity(), ColorHelper.isLightColor(color));
            }
        } else if (percentage == 1.0f) {
            if (mIsAppBarExpanded) {
                mIsAppBarExpanded = false;
                ColorHelper.setupStatusBarIconColor(getActivity(), false);
            }
        }
    });
}