问题描述

pushViewController不正常运行

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 Settingsif ([[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];}} 

解决方案

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 Settingsif (![[NSUserDefaults standardUserDefaults] boolForKey:@""FirstLaunch""]){    [[NSUserDefaults standardUserDefaults] setBool:YES forKey:@""FirstLaunch""];    [[NSUserDefaults standardUserDefaults] synchronize];    [self alertShow];}    [window makeKeyAndVisible];return YES;}