隱藏或禁用UINavigationBar中的UIBarButtonItem

Question

我正在用模態塞格展示UIViewController。 這UIViewController中繼承了一個UINavigationBar的，我已經設置的UIBarButtonItem左側導航欄：

我的問題是，當呈現的UIViewController的viewWillAppear中調用方法，我想隱藏UIBarButtonItem，但總是出現UIBarButtonItem。 我已經爲UIViewController聲明瞭一個名爲myCancelButton的UIBarButtonItem，並且我在Interface Builder中引用了它。

這是我到目前爲止已經試過（全部不工作）：

- (void) viewWillAppear:(BOOL)animated 
{ 
    [super viewWillAppear:animated]; 

    self.navigationItem.leftBarButtonItem = nil; 
    self.navigationItem.backBarButtonItem = nil; 
    self.myCancelButton = nil; 

    NSMutableArray *barButtonItems = [self.navigationItem.leftBarButtonItems mutableCopy]; 
    [barButtonItems removeObject:self.myCancelButton]; 
    self.navigationItem.leftBarButtonItems = barButtonItems; 

    [self.navigationItem.leftBarButtonItems delete:self.myCancelButton]; 

    self.navigationController.navigationItem.leftBarButtonItem = nil; 
    barButtonItems = [self.navigationController.navigationItem.leftBarButtonItems mutableCopy]; 
    [barButtonItems removeObject:self.myCancelButton]; 
    self.navigationController.navigationItem.leftBarButtonItems = barButtonItems; 

    [self.navigationController.navigationItem.leftBarButtonItems delete:self.myCancelButton]; 

    [self.myCancelButton setWidth:0.01]; 

    self.navigationItem.hidesBackButton = TRUE; 

    //Even setting enabled to false doesn't work: 
    [self.myCancelButton setEnabled:FALSE]; 
} 

Answer 1

這應該工作。

[self.navigationItem setHidesBackButton:YES animated:YES]; 

Answer 2

嘗試不幸的是使用一個

self.navigationController.navigationItem.leftBarButtonItem = nil; 
[self.navigationController.navigationItem setHidesBackButton:YES];