I would like to wait this code to be executed before to continue but as these blocks are called assynchronously I don't know how to do???
NSURL *asseturl;
NSMutableArray *tmpListAsset = [[NSMutableArray alloc] init];
ALAssetsLibrary *library = [[[ALAssetsLibrary alloc] init] autorelease];
NSMutableArray *objectsToRemove = [[NSMutableArray alloc] init];
for (NSDictionary *dico in assetsList) {
asseturl = [NSURL URLWithString:[dico objectForKey:@"assetUrl"]];
NSLog(@"asset url %@", asseturl);
// Try to load asset at mediaURL
[library assetForURL:asseturl resultBlock:^(ALAsset *asset) {
// If asset doesn't exists
if (!asset){
[objectsToRemove addObject:dico];
}else{
[tmpListAsset addObject:[asseturl absoluteString]];
NSLog(@"tmpListAsset : %@", tmpListAsset);
}
} failureBlock:^(NSError *error) {
// Type your code here for failure (when user doesn't allow location in your app)
}];
}
GCD semaphore approach:
dispatch_semaphore_t sema = dispatch_semaphore_create(0);
dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT,0);
for (NSURL *url in self.assetUrls) {
dispatch_async(queue, ^{
[library assetForURL:url resultBlock:^(ALAsset *asset) {
[self.assets addObject:asset];
dispatch_semaphore_signal(sema);
} failureBlock:^(NSError *error) {
dispatch_semaphore_signal(sema);
}];
});
dispatch_semaphore_wait(sema, DISPATCH_TIME_FOREVER);
}
dispatch_release(sema);
/* Check out ALAssets */
NSLog(@"%@", self.assets);