我想在登录过程中显示SVProgressHUD。但是SVProgressHUD在登录后仍然等待。在“登录成功”消息后，已将~15seconds取消。
这是我的代码:
[SVProgressHUD show];
__block BOOL result;
dispatch_async(queue, ^{
result = [self autanticate];
NSLog(@"autantication result = %d", result);
result = [self getCSRFToken];
NSLog(@"Login success result = %d", result);
[SVProgressHUD dismiss];
});
autanticate和getCSRFToken函数如下所示:- (BOOL) getCSRFToken
{
__block BOOL success = false;
AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager];
// Make sure that the callbacks are not called from the main queue, otherwise we would deadlock
manager.requestSerializer = [AFJSONRequestSerializer serializer];
manager.responseSerializer = [AFHTTPResponseSerializer serializer];
NSDictionary *parameters = @{@"username": self.username.text,
@"password": self.password.text};
NSLog(@"Creating CSRF semaphore");
dispatch_semaphore_t semaphore = dispatch_semaphore_create(0);
// CSRF Token bilgisini alalım
NSString *Url = [NSString stringWithFormat:@"%@%@", BaseURLString, @"?q=services/session/token"];
[manager GET:Url parameters:parameters success:^(AFHTTPRequestOperation *operation, id responseObject) {
NSLog(@"CSRF Token: %@", responseObject);
success = true;
dispatch_semaphore_signal(semaphore);
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
NSLog(@"Error: %@", error);
success = false;
dispatch_semaphore_signal(semaphore);
}];
NSLog(@"Waiting CSRF semaphore");
dispatch_semaphore_wait(semaphore, DISPATCH_TIME_FOREVER);
return success;
}
- (BOOL)autanticate
{
__block BOOL isAutanticated = false;
AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager];
manager.requestSerializer = [AFJSONRequestSerializer serializer];
manager.responseSerializer = [AFJSONResponseSerializer serializer];
NSDictionary *parameters = @{@"username": self.username.text,
@"password": self.password.text};
// Session bilgilerini alalım
NSLog(@"Creating autantication semaphore");
dispatch_semaphore_t semaphore = dispatch_semaphore_create(0);
NSString *Url = [NSString stringWithFormat:@"%@%@", BaseURLString, @"?q=rest/mserv/signin"];
[manager POST:Url parameters:parameters success:^(AFHTTPRequestOperation *operation, id responseObject) {
NSLog(@"JSON: %@", responseObject);
NSDictionary *result = [responseObject objectForKey:@"result"];
NSString *sessid = [result objectForKey:@"sessid"];
NSString *session_name = [result objectForKey:@"session_name"];
NSLog(@"sessid = %@\nsession_name=%@", sessid, session_name);
isAutanticated = true;
dispatch_semaphore_signal(semaphore);
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
NSLog(@"Error: %@", error);
isAutanticated = false;
dispatch_semaphore_signal(semaphore);
}];
NSLog(@"Waiting autanticatio semaphore");
dispatch_semaphore_wait(semaphore, DISPATCH_TIME_FOREVER);
return isAutanticated;
}
最佳答案
您必须将[SVProgressHUD dismiss]调度到主线程
[SVProgressHUD show];
__block BOOL result;
dispatch_async(queue, ^{
result = [self autanticate];
NSLog(@"autantication result = %d", result);
result = [self getCSRFToken];
NSLog(@"Login success result = %d", result);
dispatch_async(dispatch_get_main_queue(), ^{
[SVProgressHUD dismiss];
})
});
所有用户界面元素都只能在主线程上进行修改。
备注:请注意，
dispatch_async()返回(几乎)立即执行，以便不设置
result当dispatch_async()返回时。并且不要试图使用信号量来等待代码块完成。
这在后台线程上很好，但是很可能会产生死锁
在主线程上。