如何禁用iOS中的Master View控制器中的UITabBarController按鈕？

Question

當我在加載數據時通過UITabBarController按鈕選項卡時，出現異常。我怎樣才能解決這個問題？

我怎樣才能禁用按鈕，直到數據加載，以避免引起異常？

Answer 1

您可以禁用和啓用所有的UI與

[[UIApplication sharedApplication] beginIgnoringInteractionEvents]; 

[[UIApplication sharedApplication] endIgnoringInteractionEvents]; 

話雖這麼說，我建議挖下來理解爲什麼應用程序崩潰，因爲你將要解決的問題，而不是隱瞞錯誤。

一個快速拍攝：你是否正在另一個線程上加載？您只能從主線程更新UI。

Answer 2

這裏是啓用/禁用標籤欄中所有項目的代碼。

+(void) setAllItemsInTabBar:(UITabBarController *)aTabBar toEnableState:(BOOL)enableState 
{ 
    NSArray *tabItems = aTabBar.tabBar.items; 
    for (UIBarItem *tabItem in tabItems) 
    { 
     [tabItem setEnabled:enableState]; 
    } 
} 

Answer 3

解決此問題的另一種方法將符合<UITabBarControllerDelegate>協議。

@interface SomeViewController : UIViewController <UITabBarControllerDelegate> 
@property (nonatomic) BOOL tabbarShouldRespond; 
//.. 
//.. 

然後

@implementation SomeViewController 
//.. 
// become the delegate for our UITabBarController - probably in viewDidLoad 
self.tabBarController.delegate = self; 
//.. 
// set our BOOL for whether the tab bar should respond to touches based on program logic 
self.tabbarShouldRespond = NO; 
//.. 
//.. 
#pragma mark <UITabBarControllerDelegate> 
//Asks the delegate whether the specified view controller should be made active. 
- (BOOL)tabBarController:(UITabBarController *)tabBarController shouldSelectViewController:(UIViewController *)viewController { 
    if (self.tabbarShouldRespond) { 
     return YES; 
    } else { 
     return NO; 
    } 
} 

蘋果文檔 - UITabBarControllerDelegate Protocol Reference