setting imageview first

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• gmarro Posts: 9New Users

  July 2012

  Tongo;440454 said:

  
  Everything is working fine however the only problem is that after it takes the picture, it will wait till its uploaded to the server before displaying the image in the imageview. How can I display it in the imageview before it begins uploading?

  Any change you make to the user interface is taken in account by the system as soon as your method returns and the control backs to the main loop on main thread. So, as you are uploading synchronously the file, nothing changes for the user interface until that upload finishes.
  
  The easiest way to solve that is to separate the uploading in a different method. For example:
  
  -(void) uploadFile:(NSString*) path ;
  
  Then, in your actual code, you write:
  
  [self performSelector:@selector(uploadFile:) withObject:path afterDelay:0.0];
  
  then the method ends, control returns to the main loop, the user interface does the modifications and immediately the new uploadFile: method is invoked.
  
  Gabriel

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• Duncan C Posts: 8,031Tutorial Authors, Registered Users

  July 2012

  Tongo;440454 said:

  Hello
  
  I have this code
  
  

  
  
           // Place image in ImageView
  
           self.vImage.image = image;
           
           tongo.time = 13;
           
           // Upload Image to server
           
           NSData *imageDataUpload = UIImageJPEGRepresentation(vImage.image, 90);
           NSString *urlString = @\"http://website/upload.php\";
           
           NSMutableURLRequest *request = [[NSMutableURLRequest alloc] init];
           [request setURL:[NSURL URLWithString:urlString]];
           [request setHTTPMethod:@\"POST\"];
           
           NSString *boundary = [NSString stringWithString:@\"---------------------------14737809831466499882746641449\"];
           NSString *contentType = [NSString stringWithFormat:@\"multipart/form-data; boundary=%@\", boundary];
           [request addValue:contentType forHTTPHeaderField:@\"Content-Type\"];
           
           NSMutableData *body = [NSMutableData data];
           [body appendData:[[NSString stringWithFormat:@\"\r\n--%@\r\n\", boundary] dataUsingEncoding:NSUTF8StringEncoding]];    
           [body appendData:[[NSString stringWithString:@\"Content-Disposition: form-data; name=\\"userfile\\"; filename=\\".png\\"\r\n\"] dataUsingEncoding:NSUTF8StringEncoding]];
           [body appendData:[[NSString stringWithString:@\"Content-Type: application/octet-stream\r\n\r\n\"] dataUsingEncoding:NSUTF8StringEncoding]];
           [body appendData:[NSData dataWithData:imageDataUpload]];
           [body appendData:[[NSString stringWithFormat:@\"\r\n--%@--\r\n\", boundary] dataUsingEncoding:NSUTF8StringEncoding]];
           [request setHTTPBody:body];
           
           NSData *returnData = [NSURLConnection sendSynchronousRequest: request returningResponse:nil error:nil];
           NSString *returnString = [[NSString alloc] initWithData:returnData encoding:NSUTF8StringEncoding];
           
           NSLog(returnString);
           
           if (returnString) {
               self.imageLabel.text = @\"Uploaded\";
           }

  
  
  What it does is, takes a picture -> places picture in the imageview -> uploads picture to server using the php file.
  
  Everything is working fine however the only problem is that after it takes the picture, it will wait till its uploaded to the server before displaying the image in the imageview. How can I display it in the imageview before it begins uploading?

  
  You are sending your POST request synchronously. That freezes everything until the post is complete. UI changes like installing an image into an image view don't take effect until your code returns, which doesn't happen because of the synchronous POST.
  
  Rewrite your code to do the post asynchronously. You should use the NSURLConnection sendAsynchronousRequest:queue:completionHandler instead of using sendSynchronousRequest.
  
  That code might look like this:
  
  

  
  [NSURLConnection sendAsynchronousRequest: request 
    queue: dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0)
    completionHandler: ^(NSURLResponse* response, NSData* returnData, NSError* error)
    {
      NSString *returnString = [[NSString alloc] initWithData:returnData encoding:NSUTF8StringEncoding];
      NSLog(returnString);
      if (returnString) 
      {
        self.imageLabel.text = @\"Uploaded\";
      }
      [returnString release]; //Remove this line if you are using ARC
    }
  ];
  

  
  
  Disclaimer: I still struggle with the syntax for blocks that take parameters, so the syntax above may not be correct.

  Regards,
  
  Duncan C
  WareTo
  
  
  
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