A long-running Parse operation is being executed on the main thread? - ios

Question

A long-running Parse operation is being executed on the main thread is happening on this part of code from below, i can't seem to figure out how to rid the error. Any help on how to get rid of warning.
PFFile *image = (PFFile *)[wallObject objectForKey:KEY_IMAGE];
UIImageView *userImage = [[UIImageView alloc] initWithImage:[UIImage imageWithData:image.getData]];
userImage.frame = CGRectMake(0, 65, wallImageView.frame.size.width, 225);
[wallImageView addSubview:userImage];
here is the Code Below
-(void)loadWallViews
{
//Clean the scroll view
for (id viewToRemove in [self.wallScroll subviews]){
if ([viewToRemove isMemberOfClass:[UIView class]])
[viewToRemove removeFromSuperview];
}
//For every wall element, put a view in the scroll
int originY = 10;
for (PFObject *wallObject in self.imageFilesArray){
//Build the view with the image and the comments
UIView *wallImageView = [[UIView alloc] initWithFrame:CGRectMake(10, originY, self.view.frame.size.width - 20 , 330)]; //self.view.frame.size.height
//[[UIView appearance] setBackgroundColor:[UIColor redColor]]; //added for problem solve
//Add the image
PFFile *image = (PFFile *)[wallObject objectForKey:KEY_IMAGE];
UIImageView *userImage = [[UIImageView alloc] initWithImage:[UIImage imageWithData:image.getData]];
userImage.frame = CGRectMake(0, 65, wallImageView.frame.size.width, 225);
[wallImageView addSubview:userImage];
UILabel *infoLabel = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, wallImageView.frame.size.width,55)];
infoLabel.text = [wallObject objectForKey:#"newsTitle"];
infoLabel.font = [UIFont fontWithName:KEY_FONT size:20];
infoLabel.textColor = [UIColor darkGrayColor];
infoLabel.backgroundColor = [UIColor clearColor];
infoLabel.numberOfLines = 0;
[wallImageView addSubview:infoLabel];
//Add the info label (User and creation date)
NSDate *creationDate = wallObject.createdAt;
NSDateFormatter *df = [[NSDateFormatter alloc] init];
[df setDateFormat:KEY_DATEFORMAT];
//Add the comment
UILabel *commentLabel = [[UILabel alloc] initWithFrame:CGRectMake(0, 50, wallImageView.frame.size.width, 12)];
//commentLabel.text = [NSString stringWithFormat:#"Uploaded by: %#, %#", [wallObject objectForKey:#"NewsDetail"], [df stringFromDate:creationDate]];
commentLabel.text = [NSString stringWithFormat:#": %#, %#", [wallObject objectForKey:#"newsDetail"], [df stringFromDate:creationDate]];
commentLabel.font = [UIFont fontWithName:KEY_FONT size:10];
commentLabel.textColor = [UIColor lightGrayColor];
commentLabel.backgroundColor = [UIColor clearColor];
[wallImageView addSubview:commentLabel];
UILabel *readLabel = [[UILabel alloc] initWithFrame:CGRectMake(self.view.frame.size.width - 71 , 50, wallImageView.frame.size.width, 12)];
readLabel.text = #"Read more";
readLabel.font = [UIFont fontWithName:KEY_FONT size:10];
readLabel.textColor = [UIColor blueColor];
readLabel.backgroundColor = [UIColor clearColor];
[wallImageView addSubview:readLabel];
UIButton *faceBtn = [[UIButton alloc] initWithFrame:CGRectMake(2,310, 20, 20)];
[faceBtn setImage:[UIImage imageNamed:#"Facebook.png"] forState:UIControlStateNormal];
[faceBtn addTarget:self action:#selector(share:) forControlEvents:UIControlEventTouchUpInside];
[wallImageView addSubview:faceBtn];
UIButton *twitBtn = [[UIButton alloc] initWithFrame:CGRectMake(32,310, 20, 20)];
[twitBtn setImage:[UIImage imageNamed:#"Twitter.png"] forState:UIControlStateNormal];
[twitBtn addTarget:self action:#selector(share:) forControlEvents:UIControlEventTouchUpInside];
[wallImageView addSubview:twitBtn];
UIButton *tumblrBtn = [[UIButton alloc] initWithFrame:CGRectMake(62,310, 20, 20)];
[tumblrBtn setImage:[UIImage imageNamed:#"Tumblr.png"] forState:UIControlStateNormal];
[tumblrBtn addTarget:self action:#selector(share:) forControlEvents:UIControlEventTouchUpInside];
[wallImageView addSubview:tumblrBtn];
UIButton *yourBtn = [[UIButton alloc] initWithFrame:CGRectMake(92,310, 20, 20)];
[yourBtn setImage:[UIImage imageNamed:#"Flickr.png"] forState:UIControlStateNormal];
[yourBtn addTarget:self action:#selector(share:) forControlEvents:UIControlEventTouchUpInside];
[wallImageView addSubview:yourBtn];
// wallImageView = UIEdgeInsetsMake(0.0f, myCell.frame.size.width, 0.0f, 400.0f);
UIView* separatorLineView = [[UIView alloc] initWithFrame:CGRectMake(0, 343, self.view.frame.size.width, .8)];
separatorLineView.backgroundColor = [UIColor grayColor];// you can also put image here
[wallImageView addSubview:separatorLineView];
[self.wallScroll addSubview:wallImageView];
originY = originY + wallImageView.frame.size.width + 1;
}
//Set the bounds of the scroll
self.wallScroll.contentSize = CGSizeMake(self.wallScroll.frame.size.width, originY);
//Remove the activity indicator
[self.activityIndicator stopAnimating];
[self.activityIndicator removeFromSuperview];
}

Answer 1

You should first check to see if the data is available, and if so, use it, and if not, retrieve it. You will still get a warning that this is a long operation (which it could be if you have a huge amount of data in your PFFile), but it is safe. If you are only retrieving the data over the network with a block, then you will be fine.
// PFFile *imageFile
UIImage *image;
if ([imageFile isDataAvailable]) {
image = [UIImage imageWithData:[imageFile getData]];
} else {
[imageFile getDataInBackgroundWithBlock:^(NSData *data, NSError *error) {
if (error) {
// error
} else {
if (data != nil) {
image = [UIImage imageWithData:data];
}
}
}];
}
What you don't want to do is block on retrieving the data for your PFFile. If the data is available in your PFFile, you can safely call getData without a block.