来自Android Mediastore的懒惰缩略图视频

Question

I'm showing a video list with title, duration and thumb image of the media file. Since I don't want to use the fixed thumbnails size (eg: MediaStore.Video.Thumbnails.MICRO_KIND or MediaStore.Video.Thumbnails.MINI_KIND), I've decided to get the thumb URI by myself with:

thumbUri = videoThumbnailCursor.getString(videoThumbnailCursor.getColumnIndex(MediaStore.Video.Thumbnails.DATA));

All works fine, except that the thumbnails of the new added video in the MediaStore not appear immediately but only when the View begins to scroll.

This is the getView code:

public View getView(int position, View convertView, ViewGroup parent) {

            ViewHolder holder;
            String id = null;
            if (convertView == null) {
                convertView = LayoutInflater.from(vContext).inflate(
                        R.layout.listitem, parent, false);
            }
                holder = new ViewHolder();

                holder.txtTitle = (TextView) convertView
                        .findViewById(R.id.txtTitle);

                holder.txtDuration = (TextView) convertView
                        .findViewById(R.id.duration)

                holder.thumbImage = (ImageView) convertView
                        .findViewById(R.id.imgIcon);

                video_column_index = videocursor
                        .getColumnIndexOrThrow(MediaStore.Video.Media.DISPLAY_NAME);
                videocursor.moveToPosition(position);
                id = videocursor.getString(video_column_index);

                video_column_index = videocursor
                        .getColumnIndexOrThrow(MediaStore.Video.Media.DURATION);
                videocursor.moveToPosition(position);

                long duration  = videocursor.getLong(video_column_index);

                holder.txtTitle.setText(R.string.listedvideo_text);

                String converted = "";


                if(duration != 0) {

                converted = String.format(Locale.ITALIAN, "%02d:%02d", 
                        TimeUnit.MILLISECONDS.toMinutes(duration),
                        TimeUnit.MILLISECONDS.toSeconds(duration) - 
                        TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS.toMinutes(duration))
                    );

                holder.txtDuration.setText(converted);

                }

                String[] proj = { MediaStore.Video.Media._ID,
                        MediaStore.Video.Media.DISPLAY_NAME,
                        MediaStore.Video.Media.DATA };
                @SuppressWarnings("deprecation")
                Cursor cursor = managedQuery(
                        MediaStore.Video.Media.EXTERNAL_CONTENT_URI, proj,
                        MediaStore.Video.Media.DISPLAY_NAME + "=?",
                        new String[] { id }, null);

                long ids = videocursor.getLong(videocursor.getColumnIndex(MediaStore.Video.Media._ID));

                int videoId = videocursor.getInt(videocursor.getColumnIndexOrThrow(MediaStore.Video.Media._ID));

                Cursor videoThumbnailCursor = getContentResolver().query(MediaStore.Video.Thumbnails.EXTERNAL_CONTENT_URI,
                        thumbColumns, MediaStore.Video.Thumbnails.VIDEO_ID+ "=" + videoId, null, null);

                String thumbUri = "";
                if (videoThumbnailCursor.moveToFirst()) {
                    thumbUri = videoThumbnailCursor.getString(videoThumbnailCursor.getColumnIndex(MediaStore.Video.Thumbnails.DATA));
                }

                ContentResolver crThumb = getContentResolver();
                BitmapFactory.Options options = new BitmapFactory.Options();
                options.inSampleSize = 1;

                holder.thumbImage.setImageURI(Uri.parse(thumbUri));


                duration = 0;

            return convertView;
        }
    }

Answer 1

You missed the whole point of ViewHolder as you create new instances of it every call to the getView(). You need to create instance per View creation:

public View getView(int position, View convertView, ViewGroup parent) {

    ViewHolder holder;
    String id = null;
    if (convertView == null) {
        convertView = LayoutInflater.from(vContext).inflate(
                R.layout.listitem, parent, false);
        holder = new ViewHolder();

        holder.txtTitle = (TextView) convertView
                .findViewById(R.id.txtTitle);

        holder.txtDuration = (TextView) convertView
                .findViewById(R.id.duration)

        holder.thumbImage = (ImageView) convertView
                .findViewById(R.id.imgIcon);
        convertView.setTag(holder);

    } else
        holder = (ViewHolder)convertView.getTag();

   //rest of code

    return convertView;
}