[library assetForURL:url resultBlock:^(ALAsset *asset) Not execute

Question

I am getting image asset in this way when user select images from the image picker.

-(NSMutableData *)GetImageAsset :(int)index
   {
dm=[DataManager sharedManager];
NSURL *url=[dm.imgAssetsArr objectAtIndex:index];
__block NSMutableData *data;
ALAssetsLibrary *library = [[ALAssetsLibrary alloc] init];
[library assetForURL:url resultBlock:^(ALAsset *asset)
 {


         if (asset) {
             ALAssetRepresentation *representation = [asset defaultRepresentation];
             data = [NSMutableData data];
             NSError *error;
             long long bufferOffset = 0ll;
             NSInteger bufferSize = 10000;
             long long bytesRemaining = [representation size];
             uint8_t buffer[bufferSize];
             while (bytesRemaining > 0) {
                 NSUInteger bytesRead = [representation getBytes:buffer fromOffset:bufferOffset length:bufferSize error:&error];
                 if (bytesRead == 0) {
                     NSLog(@"error reading asset representation: %@", error);
                     return;
                 }
                 bytesRemaining -= bytesRead;
                 bufferOffset   += bytesRead;
                 [data appendBytes:buffer length:bytesRead];
         }



 }

 }
        failureBlock:^(NSError *error)
          {

               NSLog(@"assetForURL error = %@", error);

          }];


return data;
}

But this never go inside the block. just skip the block and go to return statement. So my data always become null. Why is that. Please help me. Thanks

Answer 1

As mentioned in the description for that method:

Discussion

This method is asynchronous.

That means you cannot return the data in the way you have coded it. Instead get the block to call some other code once the data has been retrieved.