Android菜单栏位于底部

Question

我想在我的应用程序底部实现一个菜单栏，就像我在许多主要应用程序中看到的那样，如facebook，google +，stumble等（见下图）

这方面的关键方面是它叠加在实际内容之上，当你向下滚动时，它会消失，但是当你向上滚动它会回来。

由于一堆应用程序使用这种构造，我想知道是否有一种简单的方法可以做到这一点，我只是缺少一些东西，或者它实际上是非常复杂但是这些大公司只雇用了非常好的开发人员？

关于如何解决这个问题的任何指示将不胜感激。

Answer 1

此模式通常称为“ QuickReturn UI ”。 很少有开源实现可以看一下，即QuickReturnListView

Answer 2

我已经在Facebook中实现了QuickReturn UI模式。

你可以在这里看到更多的例子 - > https://github.com/lawloretienne/QuickReturn

public class QuickReturnFacebookFragment extends Fragment {

    // region Member Variables
    private String[] mAvatarUrls;
    private String[] mDisplayNames;
    private String[] mTimestamps;
    private String[] mMessages;
    private String[] mPostImageUrls;
    private int[] mCommentCounts;
    private int[] mLikeCounts;

    @InjectView(R.id.rv)
    RecyclerView mRecyclerView;
    @InjectView(R.id.quick_return_footer_ll)
    LinearLayout mQuickReturnFooterLinearLayout;
    @InjectView(R.id.quick_return_header_tv)
    TextView mQuickReturnHeaderTextView;
    // endregion

    //region Listeners
    //endregion

    // region Constructors
    public static QuickReturnFacebookFragment newInstance() {
        QuickReturnFacebookFragment fragment = new QuickReturnFacebookFragment();
        Bundle args = new Bundle();
        fragment.setArguments(args);
        return fragment;
    }

    public QuickReturnFacebookFragment() {
    }
    // endregion

    // region Lifecycle Methods
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        mAvatarUrls = getActivity().getResources().getStringArray(R.array.avatar_urls);
        mDisplayNames = getActivity().getResources().getStringArray(R.array.display_names);
        mTimestamps = getActivity().getResources().getStringArray(R.array.facebook_timestamps);
        mMessages = getActivity().getResources().getStringArray(R.array.facebook_messages);
        mPostImageUrls = getActivity().getResources().getStringArray(R.array.facebook_post_image_urls);
        mCommentCounts = getActivity().getResources().getIntArray(R.array.facebook_comment_counts);
        mLikeCounts = getActivity().getResources().getIntArray(R.array.facebook_like_counts);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_quick_return_facebook, container, false);
        ButterKnife.inject(this, view);
        return view;
    }

    @Override
    public void onViewCreated(View view, Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);

        ArrayList<FacebookPost> posts = new ArrayList<>();
        for(int i=0; i<23; i++){
            FacebookPost post = new FacebookPost();
            post.setAvatarUrl(mAvatarUrls[i]);
            post.setDisplayName(mDisplayNames[i]);
            post.setTimestamp(mTimestamps[i]);
            post.setCommentCount(mCommentCounts[i]);
            post.setLikeCount(mLikeCounts[i]);
            post.setPostImageUrl(mPostImageUrls[i]);
            post.setMessage(mMessages[i]);
            posts.add(post);
        }

        FacebookAdapter adapter = new FacebookAdapter(getActivity(), posts);

        // use this setting to improve performance if you know that changes
        // in content do not change the layout size of the RecyclerView
        mRecyclerView.setHasFixedSize(true);

        RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(getActivity());
        mRecyclerView.setLayoutManager(layoutManager);

        mRecyclerView.setAdapter(adapter);
        mRecyclerView.addItemDecoration(new SpacesItemDecoration(QuickReturnUtils.dp2px(getActivity(), 8)));

        int headerHeight = getResources().getDimensionPixelSize(R.dimen.facebook_header_height);
        int footerHeight = getResources().getDimensionPixelSize(R.dimen.facebook_footer_height);

        int headerTranslation = -headerHeight;
        int footerTranslation = -footerHeight;

        QuickReturnRecyclerViewOnScrollListener scrollListener = new QuickReturnRecyclerViewOnScrollListener.Builder(QuickReturnViewType.BOTH)
                .header(mQuickReturnHeaderTextView)
                .minHeaderTranslation(headerTranslation)
                .footer(mQuickReturnFooterLinearLayout)
                .minFooterTranslation(-footerTranslation)
                .isSnappable(true)
                .build();
        mRecyclerView.setOnScrollListener(scrollListener);
    }

    @Override
    public void onDestroyView() {
        super.onDestroyView();
        ButterKnife.reset(this);
    }
    // endregion
}