使用ContentResolver查询媒体库并获取最新的URI。

示例代码：

ContentResolver resolver = getContentResolver();
Uri uri = MediaStore.Video.Media.EXTERNAL_CONTENT_URI;

String[] projection = new String[]{MediaStore.Video.Media._ID};
String sortOrder = MediaStore.Video.Media.DATE_MODIFIED + " DESC LIMIT 1";

Cursor cursor = resolver.query(uri, projection, null, null, sortOrder);

if (cursor.moveToFirst()) {
    long id = cursor.getLong(cursor.getColumnIndex(MediaStore.Video.Media._ID));
    Uri videoUri = ContentUris.withAppendedId(uri, id);
    // 使用videoUri进行操作
}
cursor.close();