彈出退出時的分段控制器問題

Question

我有一個分段控制器（兩個段），它位於彈出窗口中。我的prepareForSeque方法工作正常，返回正確的默認selectedSegmentIndex。但是，當我選擇其他段並退出彈出窗口時，執行popoverControllerDidDismissPopover方法時，我的應用程序崩潰，如下面的代碼片段所示。

我在做什麼錯？我希望分段控制器保留新選擇的段，並且我認爲這是popoverControllerDidDismissPopover方法的作用。很明顯，我的理解在這裏是錯誤的，但是在哪裏？預先感謝您提供的任何幫助。

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender 
{ 
    UIStoryboardPopoverSegue *popoverSegue; 
    popoverSegue = (UIStoryboardPopoverSegue *)segue; 

    UIPopoverController *popoverController; 
    popoverController = popoverSegue.popoverController; 
    popoverController.delegate = self; 

    SettingsEditorViewController *editorVC; 
    editorVC = (SettingsEditorViewController *)popoverController.contentViewController; 
    audioMessageChoiceIndex = editorVC.audioMessageChoice.selectedSegmentIndex; 
    NSLog(@"audioMessageChoiceIndex = %d", audioMessageChoiceIndex); 
} 

- (void)popoverControllerDidDismissPopover:(UIPopoverController *)popoverController 
{ 
    NSInteger *newAudioMessageChoiceIndex = (NSInteger *)((SettingsEditorViewController *)      
     popoverController.contentViewController).audioMessageChoice.selectedSegmentIndex; 

    popoverController.delegate = self;  
    SettingsEditorViewController *editorVC; 
    editorVC = (SettingsEditorViewController *)popoverController.contentViewController; 
    editorVC.audioMessageChoice.selectedSegmentIndex = *(newAudioMessageChoiceIndex); 
} 

Answer 1

我不知道你在做什麼在這裏：

- (void)popoverControllerDidDismissPopover:(UIPopoverController *)popoverController 
{ 
    NSInteger *newAudioMessageChoiceIndex = (NSInteger *)((SettingsEditorViewController *)      
     popoverController.contentViewController).audioMessageChoice.selectedSegmentIndex; 

    popoverController.delegate = self;  
    SettingsEditorViewController *editorVC; 
    editorVC = (SettingsEditorViewController *)popoverController.contentViewController; 
    editorVC.audioMessageChoice.selectedSegmentIndex = *(newAudioMessageChoiceIndex); 
} 

我猜的應用程序崩潰，因爲你正在嘗試取消引用小NSInteger作爲一個指針。

改寫：

- (void)popoverControllerDidDismissPopover:(UIPopoverController *)popoverController 
{ 
    SettingsEditorViewController * editorVC = 
      (SettingsEditorViewController *)popoverController.contentViewController; 

    NSInteger newAudioMessageChoiceIndex = editorVC.audioMessageChoice.selectedSegmentIndex; 

    editorVC.audioMessageChoice.selectedSegmentIndex = newAudioMessageChoiceIndex; 
} 

你們是不是要設置selectedSegmentIndex與它自己的價值？在委託方法中設置popover的委託沒有意義。

如果你想保留酥料餅的會話之間UISegmentedControl狀態，只要保持在主叫方的財產，並提出之前設置selectedSegmentIndex：

@property NSInteger audioMessageChoiceIndex; 

@synthesize audioMessageChoiceIndex; 

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender 
{ 
    /* ... */ 
    SettingsEditorViewController *editorVC = (SettingsEditorViewController *)popoverController.contentViewController; 
    editorVC.audioMessageChoice.selectedSegmentIndex = self.audioMessageChoiceIndex; 
} 

- (void)popoverControllerDidDismissPopover:(UIPopoverController *)popoverController 
{ 
    SettingsEditorViewController * editorVC = 
      (SettingsEditorViewController *)popoverController.contentViewController; 
    self.audioMessageChoiceIndex = editorVC.audioMessageChoice.selectedSegmentIndex; 
}