向下滚动后，ListView 不显示实际的视频文件

Posted 2023-02-25

【中文标题】向下滚动后，ListView 不显示实际的视频文件

【英文标题】：ListView doesn't show the actual video files after scroll down

【发布时间】：2016-12-01 13:00:36

【问题描述】：

在我的应用程序中，我在 ListView 中显示 SD 卡视频。 ListView 显示视频缩略图、标题、大小、持续时间。当我向下滚动时，它会显示相同的视频和缩略图，但如果我单击一个项目，它会向另一个活动显示不同的视频文件。我只想在 ListView 中显示实际视频是向下还是向上滚动。

这是我的代码。

公共类 LoadVideo 扩展 AppCompatActivity

private Cursor videoCursor;
private int video_column_index;
ListView videoList;
int count;
String[] thumbColumns = MediaStore.Video.Thumbnails.DATA,
        MediaStore.Video.Thumbnails.VIDEO_ID;

@Override
protected void onCreate(Bundle savedInstanceState) 
    super.onCreate(savedInstanceState);
    setContentView(R.layout.load_video_activity);
    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);

    init_phone_video_grid();


private void init_phone_video_grid()

    String[] proj = MediaStore.Video.Media._ID,
            MediaStore.Video.Media.DATA,
            MediaStore.Video.Media.DISPLAY_NAME,
            MediaStore.Video.Media.SIZE,
            MediaStore.Video.Media.DURATION;

    videoCursor = getContentResolver().query(MediaStore.Video.Media.EXTERNAL_CONTENT_URI, proj, null, null, null);
    count = videoCursor.getCount();

    videoList = (ListView) findViewById(R.id.videoList);
    videoList.setAdapter(new VideoAdapter(this.getApplicationContext()));
    videoList.setOnItemClickListener(videoGridListener);


private AdapterView.OnItemClickListener videoGridListener = new AdapterView.OnItemClickListener() 
    @Override
    public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) 

        video_column_index = videoCursor.getColumnIndexOrThrow(MediaStore.Video.Media.DATA);
        videoCursor.moveToPosition(i);
        String fileName = videoCursor.getString(video_column_index);
        Intent intent = new Intent(LoadVideo.this, ShowVideo.class);
        intent.putExtra("videofilename", fileName);
        startActivity(intent);
    
;

public class VideoAdapter extends BaseAdapter

    Context context;

    VideoAdapter(Context context)
    
        this.context = context;
    

    @Override
    public int getCount() 
        return count;
    

    @Override
    public Object getItem(int i) 
        return i;
    

    @Override
    public long getItemId(int i) 
        return i;
    

    @Override
    public View getView(int i, View view, ViewGroup viewGroup)
    
        ViewHolder viewHolder;
        String id;

        if (view == null)
        
            viewHolder = new ViewHolder();
            view = LayoutInflater.from(context).inflate(R.layout.list_items, viewGroup, false);

            viewHolder.titleName = (TextView) view.findViewById(R.id.title);
            viewHolder.duration = (TextView) view.findViewById(R.id.duration);
            viewHolder.size = (TextView) view.findViewById(R.id.size);
            viewHolder.thumbImage = (ImageView) view.findViewById(R.id.imageIcon);

            //Title
            video_column_index = videoCursor.getColumnIndexOrThrow(MediaStore.Video.Media.DISPLAY_NAME);
            videoCursor.moveToPosition(i);
            id = videoCursor.getString(video_column_index);
            viewHolder.titleName.setText(id);

            //Size
            video_column_index = videoCursor.getColumnIndexOrThrow(MediaStore.Video.Media.SIZE);
            videoCursor.moveToPosition(i);

            String vSize;
            long videoSize = videoCursor.getLong(video_column_index);
            double actualSizeInMB = videoSize/(1024.0 * 1024.0);
            DecimalFormat dec = new DecimalFormat("0.00");

            if (actualSizeInMB > 1)
            
                vSize = dec.format(actualSizeInMB).concat(" MB");
                viewHolder.size.setText(vSize);
            
            else
            
                vSize = dec.format(actualSizeInMB).concat(" KB");
                viewHolder.size.setText(vSize);
            

            //Duration
            video_column_index = videoCursor.getColumnIndexOrThrow(MediaStore.Video.Media.DURATION);
            videoCursor.moveToPosition(i);
            long  time = videoCursor.getLong(video_column_index);
            long seconds = time/1000;
            long minutes = seconds/60;
            seconds = seconds % 60;
            String setTime ;
            if (seconds < 10)
            
                setTime = String.valueOf(minutes) + ":0" + String.valueOf(seconds);
                viewHolder.duration.setText(setTime.concat( " | "));
            
            else
            
                setTime = String.valueOf(minutes) + ":" + String.valueOf(seconds);
                viewHolder.duration.setText(setTime.concat( " | "));
            

            //String[] proj =  MediaStore.Video.Media._ID, MediaStore.Video.Media.DISPLAY_NAME, MediaStore.Video.Media.DATA ;
            //Cursor cursor = getContentResolver().query(MediaStore.Video.Media.EXTERNAL_CONTENT_URI, proj,
                    //MediaStore.Video.Media.DISPLAY_NAME + "=?", new String[]  id , null);
            //cursor.moveToFirst();
            //long ids = cursor.getLong(cursor.getColumnIndex(MediaStore.Video.Media._ID));

            long ids = videoCursor.getInt(videoCursor.getColumnIndex(MediaStore.Video.Media._ID));
            ContentResolver crThumb = getContentResolver();
            BitmapFactory.Options options = new BitmapFactory.Options();
            options.inSampleSize = 1;
            Bitmap curThumb = MediaStore.Video.Thumbnails.getThumbnail(crThumb, ids, MediaStore.Video.Thumbnails.MICRO_KIND, options);
            viewHolder.thumbImage.setImageBitmap(curThumb);
            curThumb = null;

            //video_column_index = videoCursor.getColumnIndexOrThrow(MediaStore.Video.Media.DATA);
            //videoCursor.moveToPosition(i);
            //String path = videoCursor.getString(video_column_index);
            //Bitmap thumbnail = ThumbnailUtils.createVideoThumbnail(path, MediaStore.Video.Thumbnails.MICRO_KIND);
            //viewHolder.thumbImage.setImageBitmap(thumbnail);

            //videoThumbnailCursor.close();

        

        return view;
    

    private class ViewHolder
    
        TextView titleName;
        TextView size;
        TextView duration;
        ImageView thumbImage;
    

【问题讨论】：

您是否还看到重复的缩略图/数据？

前 6 或 7 项是实际的，然后一切都和以前一样。你能告诉我为什么会这样吗？ @哈恩

问题是您仅在视图为空时设置所有数据/图像。当你滚动时，已经创建的视图会被回收，所以在这些情况下，视图不为空，但在上面的代码中，如果视图不为空，你什么也没做。我已经发布了答案，如果清楚请告诉我

是的，它奏效了。谢谢@Hahn

【参考方案1】：

从这里开始：if(view == null)，修改你的代码如下：

if (view == null) 
        viewHolder = new ViewHolder();
        view = LayoutInflater.from(context).inflate(R.layout.list_items, viewGroup, false);
        viewHolder.titleName = (TextView) view.findViewById(R.id.title);
        viewHolder.duration = (TextView) view.findViewById(R.id.duration);
        viewHolder.size = (TextView) view.findViewById(R.id.size);
        viewHolder.thumbImage = (ImageView) view.findViewById(R.id.imageIcon);
        view.setTag(viewHolder);

  else 

        viewHolder = (ViewHolder)(view.getTag());
 
//Title.....and so on...