我想用登录界面密码保护应用程序(并且首次使用加入屏幕)。关于SO的一些答案建议测试用户是否在初始屏幕的viewdidappear中登录,如果没有登录,则以模态方式显示登录屏幕。
我尝试了这个,但代码无效。有谁知道用于呈现模态视图控制器的最新代码?注意我在故事板中创建了登录屏幕并给出了故事板ID"登录"。
- (void)viewDidAppear:(BOOL)animated
{
[super viewDidAppear:animated];
//if not logged in, modally present login screen here.
if(![[NSUserDefaults standardUserDefaults] boolForKey:@"loggedIn"]) {
// go to login screen
NSLog(@"not logged in");//this fires so logic is ok
UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"Main" bundle:nil];
UIViewController *ivc = [storyboard instantiateViewControllerWithIdentifier:@"login"];//this line gives warning it is not being used
} else {
// go to main screen
}
}
/*perhaps I should call this somewhere?
- (void)presentModalViewController:(UIViewController *)modalViewController animated:(BOOL)animated
*/
答案 0 :(得分:1)
归功于@rdelmar评论,你必须presentViewController:animated:completion: (presentModalViewController:animated:
那个ivc。
- (void)viewDidAppear:(BOOL)animated
{
[super viewDidAppear:animated];
//if not logged in, modally present login screen here.
if(![[NSUserDefaults standardUserDefaults] boolForKey:@"loggedIn"]) {
// go to login screen
NSLog(@"not logged in");//this fires so logic is ok
UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"Main" bundle:nil];
UIViewController *ivc = [storyboard instantiateViewControllerWithIdentifier:@"login"];//LOOK AT NEXT LINE
[self presentViewController:ivc animated:YES completion:nil]; //THIS LINE IS MISSING.
} else {
// go to main screen
}
}