iOS如何在已經堆疊的ViewController上調用presentViewController

Question

我試圖在已經推入的視圖控制器上像下面一樣推送視圖控制器。然而，不知何故，當我試圖推動newPersonViewController時，這個新控制器不會被推入堆棧。我不知道爲什麼Xcode抱怨我試圖添加一個不屬於層次結構的新控制器。我是否錯誤地提供了ABPeoplePickerViewController？這是newPersonViewController無法推入堆棧的原因嗎？從控制檯

消息：

警告：試圖提出有關誰的觀點是不是在窗口層次！

的代碼：

- (void)addPerson 
{ 
    ABNewPersonViewController *newPersonVC = [[ABNewPersonViewController alloc] init]; 
    newPersonVC.newPersonViewDelegate = self; 
    UINavigationController *uiNav = [[UINavigationController alloc] initWithRootViewController:newPersonVC]; 

    [self presentViewController:uiNav animated:YES completion:nil]; 
} 

- (void)showPeoplePicker 
{ 
    ABPeoplePickerNavigationController *picker = [[ABPeoplePickerNavigationController alloc] init]; 
    picker.peoplePickerDelegate = self; 

    [self presentViewController:picker animated:YES completion:nil]; 
    [picker.topViewController setEditing:YES]; 
    picker.topViewController.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemAdd target:self action:@selector(addPerson)]; 
    picker.topViewController.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemCancel target:self action:@selector(peoplePickerCancel)]; 
} 

Answer 1

的問題是，addPerson正試圖從視圖控制器，這不是電流控制器模態呈現。 self（您的原始視圖控制器）不是主動控制器。 ABPeoplePickerNavigationController是。

因此，首先，定義一個類屬性來跟蹤picker的：

@property (nonatomic, weak) ABPeoplePickerNavigationController *picker; 

然後，

• 修改showPeoplePicker設置該屬性;和
• 修改addPerson使用該屬性：

因此：

- (void)addPerson 
{ 
    ABNewPersonViewController *newPersonVC = [[ABNewPersonViewController alloc] init]; 
    newPersonVC.newPersonViewDelegate = self; 
    UINavigationController *uiNav = [[UINavigationController alloc] initWithRootViewController:newPersonVC]; 

    [self.picker presentViewController:uiNav animated:YES completion:nil]; 
} 

- (void)showPeoplePicker 
{ 
    ABPeoplePickerNavigationController *picker = [[ABPeoplePickerNavigationController alloc] init]; 
    picker.peoplePickerDelegate = self; 

    [self presentViewController:picker animated:YES completion:nil]; 
    [picker.topViewController setEditing:YES]; 
    picker.topViewController.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemAdd target:self action:@selector(addPerson)]; 
    picker.topViewController.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemCancel target:self action:@selector(peoplePickerCancel)]; 

    self.picker = picker; 
} 

- (void)newPersonViewController:(ABNewPersonViewController *)newPersonView didCompleteWithNewPerson:(ABRecordRef)person 
{ 
    [newPersonView dismissViewControllerAnimated:YES completion:nil]; 
}