所以我正在构建一个用户为自己拍照的应用程序，它将它们保存到相机胶卷中，并且我正在保存对资产 URL 的引用以在应用程序中显示它们。起初，这个模型似乎工作得很好，但随着我拍的照片越来越多，它开始收到内存警告并最终崩溃。有没有更好的方法来解决这个问题？
这就是我在应用程序启动时加载保存的照片的方式（根据加载的数量，应用程序最多冻结 10 秒）：
- (void) loadPhotosArray
{
_photos = [[NSMutableArray alloc] init];
NSData* data = [[NSUserDefaults standardUserDefaults] objectForKey: @"savedImages"];
if (data)
{
NSArray* storedUrls = [[NSArray alloc] initWithArray: [NSKeyedUnarchiver unarchiveObjectWithData: data]];
// reverse array
NSArray* urls = [[storedUrls reverseObjectEnumerator] allObjects];
for (NSURL* assetUrl in urls)
{
// Block to handle image handling success
ALAssetsLibraryAssetForURLResultBlock resultblock = ^(ALAsset *myasset)
{
ALAssetRepresentation *rep = [myasset defaultRepresentation];
CGImageRef iref = [rep fullResolutionImage];
if (iref) {
UIImage* tempImage = [UIImage imageWithCGImage:iref];
UIImage* image = [[UIImage alloc] initWithCGImage: tempImage.CGImage scale: 1.0 orientation: UIImageOrientationRight];
// Set image in imageView
[_photos addObject: image];
[[NSNotificationCenter defaultCenter] postNotificationName: @"PhotosChanged" object: self];
}
};
// Handles failure of getting image
ALAssetsLibraryAccessFailureBlock failureblock = ^(NSError *myerror)
{
NSLog(@"Can't get image - %@",[myerror localizedDescription]);
};
// Load image then call appropriate block
ALAssetsLibrary* assetslibrary = [[ALAssetsLibrary alloc] init];
[assetslibrary assetForURL: assetUrl
resultBlock: resultblock
failureBlock: failureblock];
}
}
else
{
NSLog(@"Photo storage is empty");
}
}
并保存照片：
- (void) addImageToPhotos: (UIImage*)image
{
// Store image at front of array
NSMutableArray* temp = [[NSMutableArray alloc] initWithObjects: image, nil];
// load rest of images onto temp array
for (UIImage* image in _photos)
{
[temp addObject: image];
}
_photos = nil;
_photos = [[NSMutableArray alloc] initWithArray: temp];
// [self.photos addObject: image];
[[NSNotificationCenter defaultCenter] postNotificationName: @"PhotosChanged" object: self.photos];
// save to cache
ALAssetsLibrary* library = [[ALAssetsLibrary alloc] init];
[library saveImage: image toAlbum: @kAlbumeName withCompletionBlock:^(NSError *error) {
if (error)
{
NSLog(@"Error saving");
}
}];
}