Question

我有一个驻留在弹出窗口上的分段控制器（两个段）。我的prepareForSeque方法工作正常，返回正确的默认selectedSegmentIndex。但是当我选择其他段并退出弹出窗口时，我的应用程序在执行popoverControllerDidDismissPopover方法时崩溃，如下面的代码片段所示。

我做错了什么？我希望分段控制器保留新选择的段，我认为这就是popoverControllerDidDismissPopover方法所做的。显然我的理解在这里是错误的，但在哪里？提前感谢您提供的任何帮助。

- (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

我不确定你在这做什么：

- (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);
}

我猜应用程序崩溃是因为您尝试将小NSInteger取消引用作为指针。

重写：

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

    NSInteger newAudioMessageChoiceIndex = editorVC.audioMessageChoice.selectedSegmentIndex;

    editorVC.audioMessageChoice.selectedSegmentIndex = newAudioMessageChoiceIndex;
}

您是否尝试使用自己的值设置selectedSegmentIndex？在委托方法中设置popover的委托没有意义。

如果您希望在弹出窗口会话之间保持UISegmentedControl状态，只需将其保留在调用者属性中并在显示之前设置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;
}

Popover退出问题的分段控制器

1 个答案: