pushViewController不正常运行

Question

pushViewController在AppDelegate中不正常运行，只有警报视图解除了。

代码：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {    
loginReapeat = [NSTimer scheduledTimerWithTimeInterval:60.0 target:self selector:@selector(repeatLoginProcess) userInfo:nil repeats:YES];    
//First Launch Settings
if ([[NSUserDefaults standardUserDefaults] boolForKey:@"FirstLaunch"])
{

}
else
{
    [[NSUserDefaults standardUserDefaults] setBool:YES forKey:@"FirstLaunch"];
    [[NSUserDefaults standardUserDefaults] synchronize];

    [self alertShow];
}    
[window addSubview:[navigationController view]];

[window makeKeyAndVisible];

return YES;
}     
-(void)alertShow{    
UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"Help!" message:@"Need some help to use this App? Please tap the 'Help' button." delegate:self cancelButtonTitle:@"Cancel" otherButtonTitles:@"Help",nil];
[alert show];
}
- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex{

NSString *title = [alertView buttonTitleAtIndex:buttonIndex];
if([title isEqualToString:@"Help"])
{
    SignUp *signUp = [[SignUp alloc]initWithNibName:@"SignUp" bundle:nil]
    [self.navigationController pushViewController:signUp animated:YES];

}
} 

Answer 1

原因有可能是你在执行alertview 代理方法的内部pushViewController时,当前的window还没有设置好它的rootViewcontroller .所以你可以尝试这样改一下

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {    
loginReapeat = [NSTimer scheduledTimerWithTimeInterval:60.0 target:self selector:@selector(repeatLoginProcess) userInfo:nil repeats:YES];  
[window addSubview:[navigationController view]]; //先设置window 的rootViewcontroller

//First Launch Settings
if (![[NSUserDefaults standardUserDefaults] boolForKey:@"FirstLaunch"])
{

    [[NSUserDefaults standardUserDefaults] setBool:YES forKey:@"FirstLaunch"];
    [[NSUserDefaults standardUserDefaults] synchronize];

    [self alertShow];
}    
[window makeKeyAndVisible];
return YES;
}