使用适用于 Android 的 Universal Image Loader 加载缩略图？

Question

是否可以使用适用于 android 的 Universal image Loader 加载缩略图？。我在 Sdcard 中获得了图像和视频文件的缩略图，然后我不知道如何在 gridview 中使用这个库来显示这些缩略图，所以请告诉我有人知道该怎么做吗？

我从这段代码中得到了缩略图：

protected Integer doInBackground(Integer... params) {
        // TODO Auto-generated method stub

        final String[] columns = { MediaStore.Images.Media.DATA, MediaStore.Images.Media._ID };           // Images getting
        final String orderBy = MediaStore.Images.Media.DATE_TAKEN;

        imagecursor =  mContext.getContentResolver().query(
                MediaStore.Images.Media.EXTERNAL_CONTENT_URI, columns, null,
                null, orderBy);
        int image_column_index = imagecursor.getColumnIndex(MediaStore.Images.Media._ID);
        this.count = imagecursor.getCount();
        /*this.count = params[0];

        if(count == 0)
            this.count = imagecursor.getCount();
        else if(count >= 12)

        */
        bitList = new ArrayList<Bitmap>();
        arrPathList = new ArrayList<String>();
        selectedPath = new ArrayList<String>();

        for (int i = 0; i < this.count; i++) {
            imagecursor.moveToPosition(i);
            int id = imagecursor.getInt(image_column_index);
            int dataColumnIndex = imagecursor.getColumnIndex(MediaStore.Images.Media.DATA);

            bitList.add( MediaStore.Images.Thumbnails.getThumbnail(
                    mContext.getContentResolver(), id,
                    MediaStore.Images.Thumbnails.MICRO_KIND, null));

            arrPathList.add(imagecursor.getString(dataColumnIndex));
        }

        this.durationcount = new ArrayList<String>();                                                  // Video Getting
        final String[] parameters = { MediaStore.Video.Media.DATA, MediaStore.Video.Media._ID, MediaStore.Video.Media.DURATION , MediaStore.Video.Media.MIME_TYPE}; // Videos getting
        final String orderBy_v = MediaStore.Video.Media._ID;

        videocursor = mContext.getContentResolver().query(
                MediaStore.Video.Media.EXTERNAL_CONTENT_URI, parameters, null,
                null, orderBy_v);

        int video_column_index = videocursor.getColumnIndex(MediaStore.Video.Media._ID);
        int video_column_duration = videocursor.getColumnIndexOrThrow(MediaStore.Video.VideoColumns.DURATION);           // for duration of the video
        totalCount = imagecursor.getCount() + videocursor.getCount();                         /// Checking
        durationcount_a = new String[imagecursor.getCount() + videocursor.getCount()];

        for(int i = 0; i < videocursor.getCount(); i ++){
            videocursor.moveToPosition(ii);
            int id_v = videocursor.getInt(video_column_index);
            int datacolumn_v = videocursor.getColumnIndex(MediaStore.Video.Media.DATA);
            long duration = videocursor.getInt(video_column_duration);             // getting duration of the every videos

            String hms = String.format("%02d:%02d:%02d", TimeUnit.MILLISECONDS.toHours(duration), 
                    TimeUnit.MILLISECONDS.toMinutes(duration) - TimeUnit.HOURS.toMinutes(TimeUnit.MILLISECONDS.toHours(duration)),
                    TimeUnit.MILLISECONDS.toSeconds(duration) - TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS.toMinutes(duration)));

            durationcount.add(hms);
            durationcount_a[(imagecursor.getCount()) + ii] = hms;           
            bitList.add(MediaStore.Video.Thumbnails.getThumbnail(mContext.getContentResolver(), id_v,
                    MediaStore.Video.Thumbnails.MICRO_KIND, null));
            arrPathList.add(videocursor.getString(datacolumn_v));
        }
        thumbnailsselection = new boolean[totalCount];
        return null;

    }

提前致谢。

Answer 1

您必须获取缩略图的路径或 uri 才能使用通用图像加载器加载它。

查看此内容以获取 uri：-

Get thumbnail Uri/path of the image stored in sd card + android

我也从事过相同类型的项目，并将其托管在 git-hub 上。我有两个版本，一个没有 ImageLoader，另一个有 imageloader。现在我只托管了前一个：-

这里是路径https://github.com/r4jiv007/CustomFilePicker.git

这是我使用的方法：-

private String getImageThumbnail(int id) {
        final String thumb_DATA = MediaStore.Images.Thumbnails.DATA;
        final String thumb_IMAGE_ID = MediaStore.Images.Thumbnails.IMAGE_ID;
        Uri uri = thumbUri;
        String[] projection = {thumb_DATA, thumb_IMAGE_ID};
        String selection = thumb_IMAGE_ID + "=" + id + " AND " + MediaStore.Images.Thumbnails.KIND + "=" + MediaStore.Images.Thumbnails.MINI_KIND;
        Cursor thumbCursor = getContentResolver().query(uri, projection, selection, null, null);

        String thumbPath = null;
        Bitmap thumbBitmap = null;
        if (thumbCursor != null && thumbCursor.getCount() > 0) {
            thumbCursor.moveToFirst();
            int thCulumnIndex = thumbCursor.getColumnIndex(thumb_DATA);

            thumbPath = thumbCursor.getString(thCulumnIndex);
/*
            Toast.makeText(getApplicationContext(),
                    thumbPath,
                    Toast.LENGTH_LONG).show();*/

            //  thumbBitmap = BitmapFactory.decodeFile(thumbPath);

        }
        Log.i("ImageMiniKind", thumbPath + "");
        return thumbPath;
    }

你必须使用：-

  imageLoader.displayImage("file://" + fileX.getmThumbPath() + "", imageView, options);

用于加载图像..还要注意有时没有图像缩略图！

用于加载视频文件的缩略图

private String getVideoThumbnail(int id) {
    final String thumb_DATA = MediaStore.Video.Thumbnails.DATA;
    final String thumb_VIDEO_ID = MediaStore.Video.Thumbnails.VIDEO_ID;
    Uri uri = MediaStore.Video.Thumbnails.EXTERNAL_CONTENT_URI;
    String[] projection = {thumb_DATA, thumb_VIDEO_ID};
    String selection = thumb_VIDEO_ID + "=" + id + " AND " + MediaStore.Video.Thumbnails.KIND + "=" + MediaStore.Video.Thumbnails.MINI_KIND;
    Cursor thumbCursor = getContentResolver().query(uri, projection, selection, null, null);
    String thumbPath = null;
    //  Bitmap thumbBitmap = null;
    if (thumbCursor.moveToFirst()) {

        int thCulumnIndex = thumbCursor.getColumnIndex(thumb_DATA);

        thumbPath = thumbCursor.getString(thCulumnIndex);
    }
    return thumbPath;
}

现在您所要做的就是将路径传递给 imageloader 库