How to find if image exists or not - parse - ios

Question

I have successfully retrieved the image (lets say user profile pic) from parse, and i'm displaying it in the ios app. But if there is no image in the file column, then i want to display default image which is stored in the locally (not in parse), not successful.
My simple question is, how to check if there is image or not ? Below is the simple code;
PFFile *userImage = [object objectForKey:#"profilePic"]; __block UIImage *userProfilePic =[[UIImage alloc]init];
[userImage getDataInBackgroundWithBlock:^(NSData *data, NSError *error) {
if (!error) {
//this block will execute only if there is image
if(data) {
userProfilePic = [UIImage imageWithData:data];
userPic.image=userProfilePic;
}
//this block is not at all executing. This block should execute when user doesn't have their profile uploaded
if(!data) {
UIImage *userProfileDefaultPic = [[UIImage alloc]init];
userProfileDefaultPic=[UIImage imageNamed:#"defaultprofile.png"];
userPic.image=userProfileDefaultPic;
}
}
}];
Hope you can help me. Thanks in advance.
Pradeep

Answer 1

At last found the solution !
(!data) will not execute , instead we need to check if the PFFile and the UIImage to store PFFile has image or not, like below;
PFFile *userImage = [object objectForKey:#"profilePic"];
__block UIImage *userProfilePic =[[UIImage alloc]init];
if(userImage && ![userProfilePic isEqual:[NSNull null]]) //This is important to check if the file if image is there or not and if not, then display default pic in else part
{
[userImage getDataInBackgroundWithBlock:^(NSData *data, NSError *error) {
if(!error)
{
userProfilePic = [UIImage imageWithData:data];
userPic.image=userProfilePic;
}
}];
}
else
{
userProfilePic =[UIImage imageNamed:#"defaultprofilepic.png"];
userPic.image=userProfilePic;
}

Answer 2

Your code already does that. You just need to set your image on the main thread and not background thread.
if(!data) { [dispatch_async(dispatch_get_main_queue(), ^{
UIImage *userProfileDefaultPic = [[UIImage alloc]init];
userProfileDefaultPic=[UIImage imageNamed:#"defaultprofile.png"];
userPic.image=userProfileDefaultPic;
}}];