向主線程指示對日歷訪問的異步調用已完成

Question

我想要我正在使用異步調用的日歷訪問用戶的iPhone

__block NSMutableArray* someData;
[eventStore requestAccessToEntityType:EKEntityTypeEvent completion:^(BOOL granted, NSError *error) {
    //We are going to fetch events from today to the next 1 year
    if (granted) {
        //Processing
        [someData addObject:@"Something Added"]
    }

}];

我基本上想進行一些處理，然后向另一個對象中正在執行的主線程發出信號，表明該處理已在someData完成，現在應該訪問它。

我試圖將其包裝在這樣的調度組中

dispatch_group_t group = dispatch_group_create();

dispatch_group_async(group,dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0), ^ {
    calendarData = [calender returnCalenderEvents];
});

dispatch_group_notify(group,dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0), ^ {
    NSLog(@"%@",calendarData);
});

但是，由於該調用是異步的，它仍會在完成任何實際完成之前通知該完成組。

基本上，我該如何僅向主線程發出信號，表明異步調用已完成處理，獲取結果並開始進行自己的處理

Answer 1

在viewDidLoad上添加通知
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(calendarPermissionGranted:) name:@"calendarProcessingCompleted" object:nil];

授予日歷權限后，它將在此處發布通知。

 __block NSMutableArray* someData;
    [eventStore requestAccessToEntityType:EKEntityTypeEvent completion:^(BOOL granted, NSError *error) {
        //We are going to fetch events from today to the next 1 year
        if (granted) {
            //Processing
            [someData addObject:@"Something Added"]

             dispatch_async(dispatch_get_main_queue(), ^{
                    //notify your class that processing has been done.
                  [[NSNotificationCenter defaultCenter]   postNotificationName:@"calendarProcessingCompleted" object:nil userInfo:nil];
              });
        }
}];

用方法捕獲

-(void)calendarPermissionGranted:(NSNotification *)noti{

}

可能就是您要找的東西。