objective-c - 调用 popToRootViewController 动画导致崩溃。我应该怎么做？

Question

该应用程序用于进行 body 测量。用户可以说我想测量:腿、 ARM 和脖子，在设置选项卡和主选项卡中有一个循环进行每次测量的 View 。
这是这样实现的:

我有选项卡 Controller 第一个选项卡有一个导航 Controller Storyboard上的第一个 View Controller ，并且有一个自身的序列板循环直到获得所有测量值，然后转向不同的 Controller

问题是:如果用户更改他们在设置选项卡中进行的测量，第一个选项卡需要完全重新加载，就像应用程序刚刚启动一样，清除整个导航堆栈等。

目前，选项卡 Controller 在测量选项卡中的导航 Controller 上调用 popToRootViewControllerAnimated，但这会导致崩溃。每个屏幕都有一个 slider 控件，并且在已删除的 View 上调用 titleForRow:forComponent: 导致其崩溃。

我做错了什么？!

这是标签栏 Controller 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

已更新

- (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;
}

并删除了代码 - tabBarController:didSelectViewController:

但仍然是同样的错误。我认为问题在于它试图在删除 View 后获取滑动控件的值。但 View 的某些部分必须仍然存在......？无论如何要杀死它吗？还是让一切都活着？？

Answer 1

在您的代码中:

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

几点:

1. 当resetWizardView == NO时，您可能只需要setNeedsDisplay。我认为你根本不需要它来告诉你真相。

2. 我认为您希望在最后一行中定位 viewController 而不是 [self.viewControllers objectAtIndex:0]。

[(UINavigationController*)viewController popToRootViewControllerAnimated:NO]