Received memory warning in create image file - ios

Question

I use this code get album pictures, and create file in the documents, but there will be Received memory warning, then crash。
Here is the code that I used. Can anyone tell me what did I do wrong?
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
ALAssetsLibraryAccessFailureBlock failureblock = ^(NSError *myerror){
NSLog(#"error occour =%#", [myerror localizedDescription]);
};
ALAssetsGroupEnumerationResultsBlock groupEnumerAtion = ^(ALAsset *result, NSUInteger index, BOOL *stop){
if (result!=NULL) {
//we can get all the things in the defaultRepresentation such as size info in UTI
}
//just fetching photos
if ([[result valueForProperty:ALAssetPropertyType] isEqualToString:ALAssetTypePhoto]) {
//copy image to the path:Documents/DMS/Photo
ALAssetRepresentation *rep = [result defaultRepresentation];
NSString *tt = [rep filename];
NSString *fullPath = [pathPhoto stringByAppendingFormat:#"/%#",tt];
if (![[NSFileManager defaultManager] fileExistsAtPath:fullPath]){
UIImage *image = [[UIImage alloc]initWithCGImage:[rep fullScreenImage]];
NSData *imageData = UIImagePNGRepresentation(image);
[image release];
[[NSFileManager defaultManager] createFileAtPath:fullPath contents:imageData attributes:nil];
NSLog(#"Creat image file fullPath================%#",fullPath);
//imageData = nil;
[imageData release];
}else{
NSLog(#"---------------------the image is Exist");
}
}
};
ALAssetsLibraryGroupsEnumerationResultsBlock
libraryGroupsEnumeration = ^(ALAssetsGroup* group, BOOL* stop){
if (group == nil)
{
return;
}
if (group!=nil) {
[group enumerateAssetsUsingBlock:groupEnumerAtion];
}
NSLog(#"finish--------------------------------------------");
return;
};
ALAssetsLibrary* library = [[ALAssetsLibrary alloc] init];
[library enumerateGroupsWithTypes:ALAssetsGroupSavedPhotos
usingBlock:libraryGroupsEnumeration
failureBlock:failureblock];
[library release];
[pool release];

Answer 1

Since you say that you are using the code you posted inside of a loop, I suppose that what happens is that you app is being killed due to too many auto-released objects being allocated inside of the loop.
You could try using an autorelease pool:
for (...) {
#autoreleasepool {
<your code here>
}
}
so that the autorelease pool is cleaned up at each iteration (instead of growing all along the whole loop execution).
EDIT:
if ([[result valueForProperty:ALAssetPropertyType] isEqualToString:ALAssetTypePhoto])
{
ALAssetRepresentation *rep = [result defaultRepresentation];
CGImageRef iref = [rep fullScreenImage];
NSString *tt = [rep filename];
if (iref)
{
UIImage *image = [UIImage imageWithCGImage:iref];
if(!image)
{
NSLog(#"---------------------the imageData is nil");
}
else
{
NSData *imageData = UIImagePNGRepresentation(image);
NSString *fullPath = [pathPhoto stringByAppendingFormat:#"/%#.png",tt];
NSLog(#"fullPath================%#",fullPath);
if (![[NSFileManager defaultManager] fileExistsAtPath:fullPath])
{
[[NSFileManager defaultManager] createFileAtPath:fullPath contents:imageData attributes:nil];
NSLog(#"Creat image file fullPath================%#",fullPath);
}
}
CGImageRelease(iref);
}
}