Android 仿抖音列表

当下抖音非常火热，是不是也很心动做一个类似的app吗？

那我们就用RecyclerView实现这个功能吧，关于内存的回收利用就交给RecyclerView就好了。

首先我们先说3个和视频播放暂停相关的接口

public interface OnViewPagerListener {
    /**
     * 初始化
     */
    void onInitComplete(View view);

    /**
     * 释放
     */
    void onPageRelease(boolean isNext, int position, View view);

    /**
     * 选中
     */
    void onPageSelected(int position, boolean isBottom, View view);
}

然后自定义LinearLayoutManager

public class PagerLayoutManager extends LinearLayoutManager {
    private PagerSnapHelper mPagerSnapHelper;
    private OnViewPagerListener mOnViewPagerListener;
    private RecyclerView mRecyclerView;
    private int mDrift;//位移，用来判断移动方向

    public PagerLayoutManager(Context context, int orientation) {
        super(context, orientation, false);
        init();
    }

    public PagerLayoutManager(Context context, int orientation, boolean reverseLayout) {
        super(context, orientation, reverseLayout);
        init();
    }

    private void init() {
        mPagerSnapHelper = new PagerSnapHelper();
    }

    @Override
    public void onAttachedToWindow(RecyclerView view) {
        super.onAttachedToWindow(view);
        mPagerSnapHelper.attachToRecyclerView(view);
        this.mRecyclerView = view;
        mRecyclerView.addOnChildAttachStateChangeListener(mChildAttachStateChangeListener);
    }

    @Override
    public void onLayoutChildren(RecyclerView.Recycler recycler, RecyclerView.State state) {
        super.onLayoutChildren(recycler, state);
    }

    /**
     * 滑动状态的改变
     * 缓慢拖拽-> SCROLL_STATE_DRAGGING
     * 快速滚动-> SCROLL_STATE_SETTLING
     * 空闲状态-> SCROLL_STATE_IDLE
     *
     * @param state
     */
    @Override
    public void onScrollStateChanged(int state) {
        switch (state) {
            case RecyclerView.SCROLL_STATE_IDLE:
                View viewIdle = mPagerSnapHelper.findSnapView(this);
                if (viewIdle != null) {
                    int positionIdle = getPosition(viewIdle);
                    if (mOnViewPagerListener != null && getChildCount() == 1) {
                        mOnViewPagerListener.onPageSelected(positionIdle, positionIdle == getItemCount() - 1, viewIdle);
                    }
                }
                break;
            case RecyclerView.SCROLL_STATE_DRAGGING:
                View viewDrag = mPagerSnapHelper.findSnapView(this);
                if (viewDrag != null) {
                    int positionDrag = getPosition(viewDrag);
                }
                break;
            case RecyclerView.SCROLL_STATE_SETTLING:
                View viewSettling = mPagerSnapHelper.findSnapView(this);
                if (viewSettling != null) {
                    int positionSettling = getPosition(viewSettling);
                }
                break;
        }
    }


    /**
     * 监听竖直方向的相对偏移量
     *
     * @param dy
     * @param recycler
     * @param state
     * @return
     */
    @Override
    public int scrollVerticallyBy(int dy, RecyclerView.Recycler recycler, RecyclerView.State state) {
        this.mDrift = dy;
        return super.scrollVerticallyBy(dy, recycler, state);
    }

    /**
     * 监听水平方向的相对偏移量
     *
     * @param dx
     * @param recycler
     * @param state
     * @return
     */
    @Override
    public int scrollHorizontallyBy(int dx, RecyclerView.Recycler recycler, RecyclerView.State state) {
        this.mDrift = dx;
        return super.scrollHorizontallyBy(dx, recycler, state);
    }

    /**
     * 设置监听
     *
     * @param listener
     */
    public void setOnViewPagerListener(OnViewPagerListener listener) {
        this.mOnViewPagerListener = listener;
    }

    private RecyclerView.OnChildAttachStateChangeListener mChildAttachStateChangeListener = new RecyclerView.OnChildAttachStateChangeListener() {
        /**
         * itemView依赖Window
         */
        @Override
        public void onChildViewAttachedToWindow(View view) {
            if (mOnViewPagerListener != null && getChildCount() == 1) {
                mOnViewPagerListener.onInitComplete(view);
            }
        }

        /**
         *itemView脱离Window
         */
        @Override
        public void onChildViewDetachedFromWindow(View view) {
            if (mDrift >= 0) {
                if (mOnViewPagerListener != null)
                    mOnViewPagerListener.onPageRelease(true, getPosition(view), view);
            } else {
                if (mOnViewPagerListener != null)
                    mOnViewPagerListener.onPageRelease(false, getPosition(view), view);
            }

        }
    };
}

然后大功告成直接使用

recyclerView = findViewById(R.id.recycler_view);
        PagerLayoutManager mLayoutManager = new PagerLayoutManager(this, OrientationHelper.VERTICAL);
        mDatas.addAll(DataUtils.getDatas());
        mAdapter = new VideoAdapter(this, mDatas);
        recyclerView.setLayoutManager(mLayoutManager);
        recyclerView.setAdapter(mAdapter);

        mLayoutManager.setOnViewPagerListener(new OnViewPagerListener() {
            @Override
            public void onInitComplete(View view) {
                playVideo(0, view);
            }

            @Override
            public void onPageSelected(int position, boolean isBottom, View view) {
                playVideo(position, view);
            }

            @Override
            public void onPageRelease(boolean isNext, int position, View view) {
                int index = 0;
                if (isNext) {
                    index = 0;
                } else {
                    index = 1;
                }
                releaseVideo(view);
            }
        });

/**
     * 播放视频
     */
    private void playVideo(int position, View view) {
        if (view != null) {
            mVideoView = view.findViewById(R.id.video_view);
            mVideoView.start();
        }
    }

    /**
     * 停止播放
     */
    private void releaseVideo(View view) {
        if (view != null) {
            IjkVideoView videoView = view.findViewById(R.id.video_view);
            videoView.stopPlayback();
        }
    }

github