Android獲取SD卡上圖片和視頻的縮略圖

如果我們需要快速提取圖片和視頻縮略圖可以直接訪問 android.provider.MediaStore.Images.Thumbnails 和android.provider.MediaStore.Video.Thumbnails這兩個數據庫，即可查詢出來縮略圖 。

      如何判斷文件呢? 可以通過Cursor遍歷數據庫，對比INTERNAL_CONTENT_URI字段的值，這是一個Uri，這裡保存著Android手機SD卡上的多媒體文件完整路徑。

[java]
Uri originalUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI; 
                //若為視頻則為MediaStore.Video.Media.EXTERNAL_CONTENT_URI;  
                ContentResolver cr = this.getContentResolver(); 
                Cursor cursor = cr.query(originalUri, null, null, null, null); 
                if (cursor == null) { 
                    return; 
                } 
                for (cursor.moveToFirst();!cursor.isAfterLast(); cursor.moveToNext()) { 
                    long thumbNailsId = cursor.getLong(cursor   .getColumnIndex("_ID")); 
                    Bitmap bitmap = MediaStore.Images.Thumbnails.getThumbnail(cr, 
                            thumbNailsId, Video.Thumbnails.MICRO_KIND, null); 
                    //若為視頻則為  
//                  Bitmap bitmap = MediaStore.Video.Thumbnails.getThumbnail(cr,  
//                          thumbNailsId, Video.Thumbnails.MICRO_KIND, null);  
                    return bitmap; 
                } 

Uri originalUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
    //若為視頻則為MediaStore.Video.Media.EXTERNAL_CONTENT_URI;
    ContentResolver cr = this.getContentResolver();
    Cursor cursor = cr.query(originalUri, null, null, null, null);
    if (cursor == null) {
     return;
    }
    for (cursor.moveToFirst();!cursor.isAfterLast(); cursor.moveToNext()) {
     long thumbNailsId = cursor.getLong(cursor .getColumnIndex("_ID"));
     Bitmap bitmap = MediaStore.Images.Thumbnails.getThumbnail(cr,
       thumbNailsId, Video.Thumbnails.MICRO_KIND, null);
     //若為視頻則為
//     Bitmap bitmap = MediaStore.Video.Thumbnails.getThumbnail(cr,
//       thumbNailsId, Video.Thumbnails.MICRO_KIND, null);
     return bitmap;
    }