iphone - 在用户单击后立即显示事件指示器代替登录按钮

Question

我想在我的应用程序检查用户身份验证时显示一个事件指示器来代替我的右 UIBarButtonItem。

当前发生的情况是，用户单击登录按钮，然后 UI 暂停并等待网络调用返回。建议我使用调度队列在不同的线程上运行它，但我不确定如何组合这两段代码:

调度队列:

dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
dispatch_async(queue, ^ {
//show your indicator button
dispatch_async(dispatch_get_main_queue(), ^ {
    //stop indicator when user has logged in
});
});

登录方式:

- (void) loginAction{

UIActivityIndicatorView *activityIndicator = [[UIActivityIndicatorView alloc] 
initWithFrame:CGRectMake(0, 0, 20, 20)];
[activityIndicator startAnimating];
UIBarButtonItem *activityItem = [[UIBarButtonItem alloc] 
initWithCustomView:activityIndicator];
self.navigationItem.rightBarButtonItem = activityItem;

if ([userNameTextField.text isEqualToString:@""] || [passwordTextField.text 
isEqualToString:@""]) {

UIBarButtonItem *btnGo = [[UIBarButtonItem alloc] initWithTitle:@"Login" 
style:UIBarButtonItemStyleBordered target:self action:@selector(loginAction)];
self.navigationItem.rightBarButtonItem = btnGo;
[self.navigationItem.rightBarButtonItem setTintColor:[UIColor colorWithRed:44.0/255.0 
green:160.0/255.0 blue:65.0/255.0 alpha:1.0]];

UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Invalid Login" message:@"" 
delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil, nil];
[alert show];
    return;
}

if (loginSuccess== true) {

    //continue
}

}else
{
UIBarButtonItem *btnGo = [[UIBarButtonItem alloc] initWithTitle:@"Login" 
style:UIBarButtonItemStyleBordered target:self action:@selector(loginAction)];
self.navigationItem.rightBarButtonItem = btnGo;
[self.navigationItem.rightBarButtonItem setTintColor:[UIColor colorWithRed:44.0/255.0 
green:160.0/255.0 blue:65.0/255.0 alpha:1.0]];

UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Invalid Login" message:@"" 
delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil, nil];
[alert show];
return;

}
}

Answer 1

我遇到过同样的问题。我已经这样修好了。在 viewdidload 中，我将事件指示器添加为 subview ，并在单击登录按钮时开始为指示器设置动画。然后使用 performSelector 我调用了一个包含登录服务调用的方法，最后我只是停止了指示器。它对我来说很好用。使用此代码..

.h UIActivityIndi​​catorView *activityIndi​​cator;

以.m为单位

- (void)viewDidLoad
{

    [super viewDidLoad];

    activityIndicator = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge];
    [activityIndicator setFrame:CGRectMake(0, 0, 37, 37)];
    [activityIndicator setCenter:self.view.center];
    [activityIndicator setHidesWhenStopped:YES];
    [self.view addSubview:activityIndicator];
    [self setDisplayStatusOfControls];

}


  -(IBAction)loginButton
  {

     [activityIndicator startAnimating];
     [self performSelector:@selector(Loginauthentication) withObject:nil afterDelay:0.1f];

  }

- (void) loginAction
{
//Log in authentication..



[activityIndicator stopAnimating];
}