安卓新手有个关于uri格式的疑问

如题，在安卓学习中发现uri有两种格式：file:///和content:///有什么区别？
求大神们赐教！

文件File path与content:// Uri的相互转换

content Uri to path

[java] view plaincopy

    /** 
     * Gets the corresponding path to a file from the given content:// URI 
     * @param selectedVideoUri The content:// URI to find the file path from 
     * @param contentResolver The content resolver to use to perform the query. 
     * @return the file path as a string 
     */  
    public static String getFilePathFromContentUri(Uri selectedVideoUri,  
            ContentResolver contentResolver) {  
        String filePath;  
        String[] filePathColumn = {MediaColumns.DATA};  

        Cursor cursor = contentResolver.query(selectedVideoUri, filePathColumn, null, null, null);  
//      也可用下面的方法拿到cursor  
//      Cursor cursor = this.context.managedQuery(selectedVideoUri, filePathColumn, null, null, null);  

        cursor.moveToFirst();  

        int columnIndex = cursor.getColumnIndex(filePathColumn[0]);  
        filePath = cursor.getString(columnIndex);  
        cursor.close();  
        return filePath;  
    }  

path to content Uri

[java] view plaincopy

/** 
 * Gets the content:// URI  from the given corresponding path to a file 
 * @param context 
 * @param imageFile 
 * @return content Uri 
 */  
public static Uri getImageContentUri(Context context, java.io.File imageFile) {  
       String filePath = imageFile.getAbsolutePath();  
       Cursor cursor = context.getContentResolver().query(  
               MediaStore.Images.Media.EXTERNAL_CONTENT_URI,  
               new String[] { MediaStore.Images.Media._ID },  
               MediaStore.Images.Media.DATA + "=? ",  
               new String[] { filePath }, null);  
       if (cursor != null && cursor.moveToFirst()) {  
           int id = cursor.getInt(cursor  
                   .getColumnIndex(MediaStore.MediaColumns._ID));  
           Uri baseUri = Uri.parse("content://media/external/images/media");  
           return Uri.withAppendedPath(baseUri, "" + id);  
       } else {  
           if (imageFile.exists()) {  
               ContentValues values = new ContentValues();  
               values.put(MediaStore.Images.Media.DATA, filePath);  
               return context.getContentResolver().insert(  
                       MediaStore.Images.Media.EXTERNAL_CONTENT_URI, values);  
           } else {  
               return null;  
           }  
       }  
   }  



        另外，一篇[Android数据的四种存储体式格式SharePreference、SQLite、Content Provider和File...

](http://blog.sina.com.cn/s/blog_a227c5730101avnd.html "")

均可以参考参考

参考： http://blog.csdn.net/thini/article/details/9980007