Android使用ViewPager加载图片和轮播视频

作为Android基础组件之一，大家对viewpager已经很熟悉了，网上也有很多使用viewpager来加载图片的案例。但是像微信那样点击图片，可以轮播显示图片和视频的例子却没找到。正巧项目中有需求，可以就花时间写了下，现在给一下核心代码，希望对有此需求的同学们起一个抛砖引玉的作用。话不多说了，上代码：

以下是initData的代码

public void initData() {
  //把聊天界面的图片和视频找出来，并加到数组中，并在
  //并根据传进来的position来找到视频或图片在数组中的位置
  for (int i = 0; i < MsgCount; i++) {
   Msg1 msg1 = fridenMessages.MessageList.get(i);
   if (msg1.getMsg().startsWith(ChatUtil.TAG_IMAGE) || msg1.getMsg().startsWith(ChatUtil.TAG_VIDEO)) {
    ImageUrl.add(msg1.getMsg());
    //查看消息postion对应的图片位置
    if (position == i) {
     position = ImageUrl.size() - 1;
     Log.i("TAG", "position=" + position);
    }

   }
  }
  Log.i("TAG", "position=" + position);
  //把要用到的view加到viewList中
  for (int i = 0; i < ImageUrl.size(); i++) {
   if (ImageUrl.get(i).startsWith(ChatUtil.TAG_IMAGE)) {
    PhotoView photoView = new PhotoView(context);
    viewList.add(photoView);
   } else if (ImageUrl.get(i).startsWith(ChatUtil.TAG_VIDEO)) {

    View view1 = LayoutInflater.from(context).inflate(R.layout.activity_video_player, null);
    SurfaceVideoView videoView = (SurfaceVideoView) view1.findViewById(R.id.videoview);
    int screenWidth = getScreenWidth((Activity) context);
    int videoHight = (int) (screenWidth / (MediaRecorderBase.SMALL_VIDEO_WIDTH / (MediaRecorderBase.SMALL_VIDEO_HEIGHT * 1.0f)));
//    int videoHight = (int) (screenWidth)*4/3;
    videoView.getLayoutParams().height = videoHight;
    videoView.requestLayout();
    View playStatus = view1.findViewById(R.id.play_status);
    View loading = view1.findViewById(R.id.loading);
    viewList.add(view1);
   }
  }

  adapter = new MyAdapter();
  viewPager.setAdapter(adapter);
  if (position != -1) {
   viewPager.setCurrentItem(position);
  }
 }
``` public void initEvent() {
  //给viewPager设置监听
  viewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {

   @Override
   public void onPageSelected(int arg0) {

    int childCount = viewPager.getChildCount();//viewPager得到页面的数量
    //如果不是在原页面，让原来页面的视频停止播放
    if(position != arg0){
     position=arg0;
     StopVideo();
    }

    // 遍历当前所有加载过的PhotoView，恢复所有图片的默认状态

    for (int i = 0; i < childCount; i++) {
     View childAt = viewPager.getChildAt(i);

     try {
      if (childAt != null && childAt instanceof PhotoView) {
       PhotoView photoView = (PhotoView) childAt;
       photoView.setOnPhotoTapListener(new PhotoViewAttacher.OnPhotoTapListener() {
        @Override
        public void onPhotoTap(View view, float x, float y) {
         finish();
        }

        @Override
        public void onOutsidePhotoTap() {

        }
       });
      }
     } catch (Exception e) {
      e.printStackTrace();
     }
    }
    if (ImageUrl.get(position).startsWith(ChatUtil.TAG_VIDEO)) {
     String body = ChatApplication.dbHelper.getVideoSdPath(ImageUrl.get(position));
     String url[] = ImageUrl.get(position).substring(ChatUtil.TAG_VIDEO.length()).split("&&");
     View childAt = viewList.get(arg0);
     SurfaceVideoView videoView = (SurfaceVideoView) childAt.findViewById(R.id.videoview);
     mVideoView = videoView;
     mPlayerStatus = childAt.findViewById(R.id.play_status);
     mLoading = childAt.findViewById(R.id.loading);
     Log.i("TAG", "videoUrl=" + body);
     setVideoUrl(body, url);
     //延迟50ms，让播放器播放视频时，让它暂停
     Handler handler = new Handler();
     handler.postDelayed(new Runnable() {
      @Override
      public void run() {
       StopVideo();
      }
     }, 50);
    }
   }

   @Override
   public void onPageScrolled(int arg0, float arg1, int arg2) {
    // TODO Auto-generated method stub

   }

   @Override
   public void onPageScrollStateChanged(int arg0) {
    // TODO Auto-generated method stub

   }
  });
 }
 public class MyAdapter extends PagerAdapter {

  @Override
  public int getCount() {
   return ImageUrl.size();
  }

  @Override
  public View instantiateItem(ViewGroup container, int pos) {
   Log.i("TAG", "pos=" + pos);
   if (ImageUrl.get(pos).startsWith(ChatUtil.TAG_IMAGE)) {
    PhotoView photoView = (PhotoView) viewList.get(pos);
    container.addView(photoView, ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT);
    String body[] = ImageUrl.get(pos).substring(ChatUtil.TAG_IMAGE.length()).split("&&");
    Log.i("TAG", "<IMAGE>=" + body[0]);
    ImageLoader.getInstance().displayImage(body[0], photoView);
    photoView.setScaleType(ImageView.ScaleType.FIT_CENTER);//设置图片显示为充满全屏
    photoView.setOnPhotoTapListener(new PhotoViewAttacher.OnPhotoTapListener() {
     @Override
     public void onPhotoTap(View view, float x, float y) {
      finish();
     }

     @Override
     public void onOutsidePhotoTap() {

     }
    });
    //   photoView.setOnLongClickListener(longClickListener);

   } else if (ImageUrl.get(pos).startsWith(ChatUtil.TAG_VIDEO)) {
     View view1 = viewList.get(pos);
    SurfaceVideoView VideoView = (SurfaceVideoView) view1.findViewById(R.id.videoview);
    int screenWidth = getScreenWidth((Activity) context);
    int videoHight = (int) (screenWidth / (MediaRecorderBase.SMALL_VIDEO_WIDTH / (MediaRecorderBase.SMALL_VIDEO_HEIGHT * 1.0f)));
//    int videoHight = (int) (screenWidth)*4/3;
    VideoView.getLayoutParams().height = videoHight;
    VideoView.requestLayout();
    View PlayerStatus = view1.findViewById(R.id.play_status);
    View Loading = view1.findViewById(R.id.loading);
    VideoView.setOnPreparedListener(ShowBigPictureActivity.this);
    VideoView.setOnPlayStateListener(ShowBigPictureActivity.this);
    VideoView.setOnErrorListener(ShowBigPictureActivity.this);
    VideoView.setOnClickListener(ShowBigPictureActivity.this);
    VideoView.setOnInfoListener(ShowBigPictureActivity.this);
    VideoView.setOnCompletionListener(ShowBigPictureActivity.this);
    container.addView(view1, ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT);

    String body = ChatApplication.dbHelper.getVideoSdPath(ImageUrl.get(pos));
    String url[] = ImageUrl.get(pos).substring(ChatUtil.TAG_VIDEO.length()).split("&&");
    //找到是点击聊天界面哪个视频进来的，将局部成员，付给类成员
    if(pos==position) {
     mVideoView = VideoView;
     mPlayerStatus=PlayerStatus;
     mLoading=Loading;
     setVideoUrl(body,url);

    }

   }

   return viewList.get(pos);
  }

  @Override
  public void destroyItem(ViewGroup container, int position, Object object) {
   container.removeView((View) object);
  }

  @Override
  public boolean isViewFromObject(View view, Object object) {
   return view == object;
  }
 }
以下是控制视频播放的接口：
 public void onCompletion(MediaPlayer mp) {
  onStateChanged(false);
 }

 @Override
 public boolean onError(MediaPlayer mp, int what, int extra) {

  return false;

 }

 @Override
 public boolean onInfo(MediaPlayer mp, int what, int extra) {
  switch (what) {
   case MediaPlayer.MEDIA_INFO_BAD_INTERLEAVING:
    // 音频和视频数据不正确
    ConfigUtil.showShort(context, "视频数据不正确！");
    break;
   case MediaPlayer.MEDIA_INFO_BUFFERING_START:
    if (!isFinishing())
     mVideoView.pause();
    break;
   case MediaPlayer.MEDIA_INFO_BUFFERING_END:
    if (!isFinishing())
     mVideoView.start();
    break;
   case MediaPlayer.MEDIA_INFO_VIDEO_RENDERING_START:
    if (DeviceUtils.hasJellyBean()) {
     mVideoView.setBackground(null);
    } else {
     mVideoView.setBackgroundDrawable(null);
    }
  break;
 }
 return false;
}

 @Override
 public void onStateChanged(boolean isPlaying) {
  mPlayerStatus.setVisibility(isPlaying ? View.GONE : View.VISIBLE);

 }

 @Override
 public void onPrepared(MediaPlayer mp) {
  mVideoView.setVolume(SurfaceVideoView.getSystemVolumn(this));
  mVideoView.start();
  mLoading.setVisibility(View.GONE);

 }

我觉得轮播视频的难点在于viewpager只能播放一个视频，而每个viewItem都有继承自SurfaceView的SurfaceVideoView控件， 我让原先页面的SurfaceViedeoView停止播放，并把新页面的SurfaceVideoView付给mVideoView，然后就可以对选中页面的视频进行控制了。

下面来张效果图：

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