奇怪的延迟来更新TextField [英] Strange Delay to Update TextField

问题描述

我正在获取Facebook用户数据以自动完成注册文本字段.

Im getting Facebook User Data to auto completing signup textfields.

问题:我做了一个测试，NSLog快速返回了信息，但是要更新TextFields.text，它会延迟.

Problem: I did a test and NSLog returns information quickly, but to update the TextFields.text it's delaying.

代码:

- (IBAction)facebookProfile:(id)sender {
    if(!_accountStore)
        _accountStore = [[ACAccountStore alloc] init];

    ACAccountType *facebookTypeAccount = [_accountStore accountTypeWithAccountTypeIdentifier:ACAccountTypeIdentifierFacebook];

    [_accountStore requestAccessToAccountsWithType:facebookTypeAccount
                                           options:@{ACFacebookAppIdKey: @"417425124162461", ACFacebookPermissionsKey: @[@"email"]}
                                        completion:^(BOOL granted, NSError *error) {
                                            if(granted){
                                                NSArray *accounts = [_accountStore accountsWithAccountType:facebookTypeAccount];
                                                _facebookAccount = [accounts lastObject];
                                                NSLog(@"Success");

                                                [self me];
                                            }else{
                                                // ouch
                                                NSLog(@"Fail");
                                                NSLog(@"Error: %@", error);
                                            }
                                        }];
}

- (void)me {
    NSURL *meUrl = [NSURL URLWithString:@"https://graph.facebook.com/me"];
    SLRequest *meRequest = [SLRequest requestForServiceType:SLServiceTypeFacebook requestMethod:SLRequestMethodGET URL:meUrl parameters:nil];

    meRequest.account = _facebookAccount;

    [meRequest performRequestWithHandler:^(NSData *responseData, NSHTTPURLResponse *urlResponse, NSError *error) {

        if (!error) {
            NSDictionary *resultsDictionary = [responseData objectFromJSONData];

            NSLog(@"%@", [resultsDictionary objectForKey:@"name"]);

            // The problem is here. While NSLog runs in seconds showing Facebook User Name, the textfiend.text updates take about 10 seconds longer.

            _tfName.text = [resultsDictionary objectForKey:@"name"];
            _tfEmail.text = [resultsDictionary objectForKey:@"email"];
            _tfGender.text = [resultsDictionary objectForKey:@"gender"];
            _tfBirthday.text = [resultsDictionary objectForKey:@"birthday"];
        }

    }];    
}

推荐答案

您需要在主线程上执行UI更新.您的完成处理程序正在后台线程上被调用.

You need to perform UI updates on the main thread. Your completion handler is being called on a background thread.

[meRequest performRequestWithHandler:^(NSData *responseData, NSHTTPURLResponse *urlResponse, NSError *error) {

    if (!error) {
        NSDictionary *resultsDictionary = [responseData objectFromJSONData];

        NSLog(@"%@", [resultsDictionary objectForKey:@"name"]);

        // The problem is here. While NSLog runs in seconds showing Facebook User Name, the textfiend.text updates take about 10 seconds longer.

        // Ensure UI updated on main queue
        dispatch_async(dispatch_get_main_queue(), ^{
            _tfName.text = [resultsDictionary objectForKey:@"name"];
            _tfEmail.text = [resultsDictionary objectForKey:@"email"];
            _tfGender.text = [resultsDictionary objectForKey:@"gender"];
            _tfBirthday.text = [resultsDictionary objectForKey:@"birthday"];
        });
    }

}];    

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