这里简单实现抖音主界面如下（点击查看GitHub上的Demo）：
抖音主界面视频这里采用RecyclerView来实现视频滚动，我们知道RecyclerView是要靠LayoutManager来管理的，我们自己来简单实现一个这个功能，重写LayoutManager。
1：自定义LayoutManager管理类如下：
package com.example.administrator.douyin;
import android.content.Context;
import android.support.annotation.NonNull;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.PagerSnapHelper;
import android.support.v7.widget.RecyclerView;
import android.view.View;
/**
* 自定义LayoutManager来实现RecyclerView的管理
*
*/
public class MyLayoutManager extends LinearLayoutManager implements RecyclerView.OnChildAttachStateChangeListener {
private int mDrift;//位移，用来判断移动方向
private PagerSnapHelper mPagerSnapHelper;
private OnViewPagerListener mOnViewPagerListener;
public MyLayoutManager(Context context) {
super(context);
}
public MyLayoutManager(Context context, int orientation, boolean reverseLayout) {
super(context, orientation, reverseLayout);
mPagerSnapHelper = new PagerSnapHelper();
}
@Override
public void onAttachedToWindow(RecyclerView view) {
view.addOnChildAttachStateChangeListener(this);
mPagerSnapHelper.attachToRecyclerView(view);
super.onAttachedToWindow(view);
}
//当Item添加进来了 调用这个方法
//
@Override
public void onChildViewAttachedToWindow(@NonNull View view) {
// 播放视频操作 即将要播放的是上一个视频 还是下一个视频
if (mDrift > 0) {
// 向上
if (mOnViewPagerListener != null) {
mOnViewPagerListener.onPageSelected(getPosition(view), true);
}
}else {
if (mOnViewPagerListener != null) {
mOnViewPagerListener.onPageSelected(getPosition(view), false);
}
}
}
public void setOnViewPagerListener(OnViewPagerListener mOnViewPagerListener) {
this.mOnViewPagerListener = mOnViewPagerListener;
}
@Override
public void onScrollStateChanged(int state) {
switch (state) {
case RecyclerView.SCROLL_STATE_IDLE:
View view= mPagerSnapHelper.findSnapView(this);
int position = getPosition(view);
if (mOnViewPagerListener != null)
{
mOnViewPagerListener.onPageSelected(position, position == getItemCount() - 1);
}
// postion ---回调 ----》播放
break;
}
super.onScrollStateChanged(state);
}
@Override
public void onChildViewDetachedFromWindow(@NonNull View view) {
//暂停播放操作
if (mDrift >= 0){
if (mOnViewPagerListener != null) mOnViewPagerListener.onPageRelease(true,getPosition(view));
}else {
if (mOnViewPagerListener != null) mOnViewPagerListener.onPageRelease(false,getPosition(view));
}
}
@Override
public int scrollVerticallyBy(int dy, RecyclerView.Recycler recycler, RecyclerView.State state) {
this.mDrift = dy;
return super.scrollVerticallyBy(dy, recycler, state);
}
@Override
public boolean canScrollVertically() {
return true;
}
}
2：主界面代码如下所示：
/**
* 进入抖音首页
* create by andyYuan317 on 2020/05/01
*/
public class MainActivity extends AppCompatActivity {
private static final String TAG = "test";
private RecyclerView mRecyclerView;
private MyAdapter mAdapter;
MyLayoutManager myLayoutManager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initView();
initListener();
}
private void initView() {
mRecyclerView = findViewById(R.id.recycler);
myLayoutManager = new MyLayoutManager(this, OrientationHelper.VERTICAL,false);
mAdapter = new MyAdapter();
mRecyclerView.setLayoutManager(myLayoutManager);
mRecyclerView.setAdapter(mAdapter);
}
private void initListener(){
myLayoutManager.setOnViewPagerListener(new OnViewPagerListener() {
@Override
public void onInitComplete() {
}
@Override
public void onPageRelease(boolean isNext, int position) {
Log.e(TAG,"释放位置:"+position +" 下一页:"+isNext);
int index = 0;
if (isNext){
index = 0;
}else {
index = 1;
}
releaseVideo(index);
}
@Override
public void onPageSelected(int position, boolean isNext) {
Log.e(TAG,"释放位置:"+position +" 下一页:"+isNext);
int index = 0;
if (isNext){
index = 0;
}else {
index = 1;
}
playVideo(index);
}
});
}
class MyAdapter extends RecyclerView.Adapter<MyAdapter.ViewHolder>{
private int[] imgs = {R.mipmap.img_video_1,R.mipmap.img_video_2};
private int[] videos = {R.raw.video_1,R.raw.video_2};
public MyAdapter(){
}
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_view_pager,parent,false);
return new ViewHolder(view);
}
@Override
public void onBindViewHolder(ViewHolder holder, int position) {
holder.img_thumb.setImageResource(imgs[position%2]);
holder.videoView.setVideoURI(Uri.parse("android.resource://"+getPackageName()+"/"+ videos[position%2]));
}
@Override
public int getItemCount() {
return 20;
}
public class ViewHolder extends RecyclerView.ViewHolder{
ImageView img_thumb;
VideoView videoView;
ImageView img_play;
RelativeLayout rootView;
public ViewHolder(View itemView) {
super(itemView);
img_thumb = itemView.findViewById(R.id.img_thumb);
videoView = itemView.findViewById(R.id.video_view);
img_play = itemView.findViewById(R.id.img_play);
rootView = itemView.findViewById(R.id.root_view);
}
}
}
private void releaseVideo(int index){
View itemView = mRecyclerView.getChildAt(index);
final VideoView videoView = itemView.findViewById(R.id.video_view);
final ImageView imgThumb = itemView.findViewById(R.id.img_thumb);
final ImageView imgPlay = itemView.findViewById(R.id.img_play);
videoView.stopPlayback();
imgThumb.animate().alpha(1).start();
imgPlay.animate().alpha(0f).start();
}
@TargetApi(Build.VERSION_CODES.JELLY_BEAN_MR1)
private void playVideo(int position) {
View itemView = mRecyclerView.getChildAt(0);
final VideoView videoView = itemView.findViewById(R.id.video_view);
final ImageView imgPlay = itemView.findViewById(R.id.img_play);
final ImageView imgThumb = itemView.findViewById(R.id.img_thumb);
final RelativeLayout rootView = itemView.findViewById(R.id.root_view);
final MediaPlayer[] mediaPlayer = new MediaPlayer[1];
videoView.start();
videoView.setOnInfoListener(new MediaPlayer.OnInfoListener() {
@Override
public boolean onInfo(MediaPlayer mp, int what, int extra) {
mediaPlayer[0] = mp;
mp.setLooping(true);
imgThumb.animate().alpha(0).setDuration(200).start();
return false;
}
});
videoView.setOnPreparedListener(new MediaPlayer.OnPreparedListener() {
@Override
public void onPrepared(MediaPlayer mp) {
}
});
imgPlay.setOnClickListener(new View.OnClickListener() {
boolean isPlaying = true;
@Override
public void onClick(View v) {
if (videoView.isPlaying()){
imgPlay.animate().alpha(1f).start();
videoView.pause();
isPlaying = false;
}else {
imgPlay.animate().alpha(0f).start();
videoView.start();
isPlaying = true;
}
}
});
}
}