objective-c - 调用popToRootViewControllerAnimated导致崩溃。我应该怎么做？

该应用程序用于进行身体测量。用户可以说我要测量：腿，胳膊和脖子，在“设置”选项卡和主选项卡中，有一个视图，可以循环显示每次测量。
这样实现：

我有标签控制器
第一个标签有一个导航控制器
情节提要上的第一个视图控制器，本身具有一个segue
电路板不断循环，直到完成所有测量，然后选择另一个控制器

问题是：如果用户在“设置”选项卡中更改了要进行的测量，则第一个选项卡需要完全重新加载，就好像该应用程序刚刚启动，清理整个导航堆栈等。

目前，标签控制器在“测量”标签中的导航控制器上调用popToRootViewControllerAnimated，但这会导致崩溃。每个屏幕都有一个滑块控件，并在已删除的视图上调用titleForRow：forComponent：导致其崩溃。

我究竟做错了什么？！

这是标签栏控制器代码

//  TabBarController.m
//

#import "TabBarController.h"
#import "TodaysMeasurementObject.h"
#import "AppDelegateProtocol.h"
#import "AddMeasurementViewController.h"
#import "ReadPerson.h"
#import "AppDelegate.h"

@interface TabBarController () <UITabBarControllerDelegate>



@end

@implementation TabBarController

bool resetWizardView = false;

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
    }
    return self;
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    self.delegate = self;

    [[UIDevice currentDevice] beginGeneratingDeviceOrientationNotifications];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(orientationChanged:)
                                                 name:UIDeviceOrientationDidChangeNotification object:nil];

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(measurementsSettingsUpdated:) name:@"MeasurementsSettingsUpdated" object:nil];

}

- (void) measurementsSettingsUpdated:(NSNotification *) notification
{
//    UINavigationController *navigationController = [self.viewControllers objectAtIndex:0];
//    AddMeasurementViewController *addMeasurement = [[AddMeasurementViewController alloc] init];
//    [navigationController setViewControllers: [[NSArray alloc] initWithObjects:addMeasurement, nil]];
    resetWizardView = YES;
}

- (void) viewDidAppear:(BOOL)animated
{
    if (![ReadPerson userHasRecords]) {
        [self setSelectedIndex:3];
    }
}

- (void)orientationChanged:(NSNotification *)notification
{
    // We must add a delay here, otherwise we'll swap in the new view
    // too quickly and we'll get an animation glitch
    [self performSelector:@selector(showGraphs) withObject:nil afterDelay:0];
}

- (void)showGraphs
{
    UIDeviceOrientation deviceOrientation = [UIDevice currentDevice].orientation;
    if (deviceOrientation == UIDeviceOrientationLandscapeLeft && !isShowingLandscapeView)
    {
        [self performSegueWithIdentifier: @"toGraph" sender: self];
        isShowingLandscapeView = YES;
    }

    else if (deviceOrientation != UIDeviceOrientationLandscapeLeft && isShowingLandscapeView)
    {
        [self dismissModalViewControllerAnimated:YES];
        isShowingLandscapeView = NO;
    }
}

- (void)viewDidUnload
{
    [super viewDidUnload];
    // Release any retained subviews of the main view.
}

- (void)dealloc
{
    [[NSNotificationCenter defaultCenter] removeObserver:self];
    [[UIDevice currentDevice] endGeneratingDeviceOrientationNotifications];
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    if(interfaceOrientation == UIInterfaceOrientationLandscapeRight)
    {
        [self performSegueWithIdentifier: @"toGraph" sender: self];
    }

    return false;
}

- (void)tabBarController:(UITabBarController *)tabBarController didSelectViewController:(UIViewController *)viewController {
    int tbi = tabBarController.selectedIndex;
    if (tbi == 0) {
        [[viewController view] setNeedsDisplay];
        if (resetWizardView) {
            [(UINavigationController*)[self.viewControllers objectAtIndex:0] popToRootViewControllerAnimated: NO]; // ******* POP CALLED HERE ******
            resetWizardView = false;
        }
    }
}

- (TodaysMeasurementObject*) theAppDataObject
{
    id<AppDelegateProtocol> theDelegate = (id<AppDelegateProtocol>) [UIApplication sharedApplication].delegate;
    TodaysMeasurementObject* theDataObject;
    theDataObject = (TodaysMeasurementObject*) theDelegate.theAppDataObject;
    return theDataObject;
}

- (BOOL)shouldAutorotate {
    return NO;
}

- (NSUInteger)supportedInterfaceOrientations {
    return UIInterfaceOrientationMaskPortrait;
}


@end

更新

- (void) measurementsSettingsUpdated:(NSNotification *) notification
{
    NSMutableArray *viewControllers = [[NSMutableArray alloc] initWithArray: self.viewControllers];
    UINavigationController *navigationController = [viewControllers objectAtIndex:0];
    AddMeasurementViewController *addMeasurement = [[AddMeasurementViewController alloc] init];
    [navigationController setViewControllers: [[NSArray alloc] initWithObjects:addMeasurement, nil]];

    [viewControllers setObject:navigationController atIndexedSubscript:0];

    self.viewControllers = viewControllers;
}

并从中删除了代码
    -tabBarController：didSelectViewController：

但仍然是相同的错误。我认为问题在于删除视图后，它正在尝试获取幻灯片控件的值。但是视图的某些部分必须仍然活着……？无论如何要杀死它？还是活着呢？

最佳答案

在您的代码中：

    [[viewController view] setNeedsDisplay];
    if (resetWizardView) {
        [(UINavigationController*)[self.viewControllers objectAtIndex:0] popToRootViewControllerAnimated: NO]; // ******* POP CALLED HERE ******

要点：


当setNeedsDisplay时，您可能只需要resetWizardView == NO。我认为您根本不需要告诉您真相。
我认为您想在最后一行中定位viewController而不是[self.viewControllers objectAtIndex:0]。


[(UINavigationController*)viewController popToRootViewControllerAnimated:NO]

关于objective-c - 调用popToRootViewControllerAnimated导致崩溃。我应该怎么做？，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/13341265/