如何判断文件呢? 可以通过Cursor遍历数据库，对比INTERNAL_CONTENT_URI字段的值，这是一个Uri，这里保存着Android手机SD卡上的多媒体文件完整路径。

[java]

复制代码 代码如下:

Uri originalUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;

//若为视频则为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);

//若为视频则为

// Bitmap bitmap = MediaStore.Video.Thumbnails.getThumbnail(cr,

// thumbNailsId, Video.Thumbnails.MICRO_KIND, null);

return bitmap;

}

Uri originalUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;

//若为视频则为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);

//若为视频则为

// Bitmap bitmap = MediaStore.Video.Thumbnails.getThumbnail(cr,

// thumbNailsId, Video.Thumbnails.MICRO_KIND, null);

return bitmap;

}