ios - dismissViewControllerAnimated 不会释放 viewcontroller

标签 ios objective-c storyboard automatic-ref-counting dealloc

首先:我的项目启用了 ARC，并且我正在使用 Storyboard。

我有一个推送 segue(模态)的 View Controller ，

[self performSegueWithIdentifier: @"goInitialSettings" sender: self];

我正在设置一些参数并存储它们。存储参数后(真正的按钮点击)，应用程序应返回到原始 View Controller 。

这是我用这个命令做的:

[self.presentingViewController dismissViewControllerAnimated:NO completion:^{}];

我注意到我关闭的 View Controller 从不解除分配。这是怎么来的？

我在下面添加“presented viewcontroller”的代码:

@interface CenterChoiceController ()
{
    UIView* _titleBackground;
    UILabel* _lblTitle;
    UIButton* _btnGaVerder;
    UIPickerView* _myPickerView;

    NSArray* _centers;
    UILabel* _adresLine;
    UILabel* _cityLine;
    MKPointAnnotation* _point;
    MKMapView* _mapView;
    UIActivityIndicatorView* _indicator;
    UIAlertView* _alert;
    GCenter* _center;
    DataManager* _dm;
}
@end

@implementation CenterChoiceController


-(void)dealloc
{
    NSLog(@"Centerchoice deallocs");

    _titleBackground = nil;
    _lblTitle = nil;
    _btnGaVerder = nil;
    _myPickerView = nil;
    _point = nil;
    _mapView = nil;
    _indicator = nil;
    _alert = nil;
    _centers = nil;
    _adresLine = nil;
    _cityLine = nil;
    _center = nil;
    _dm = nil;
}

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

- (void)viewDidLoad
{
    [super viewDidLoad];

    _dm = [[DataManager alloc]init];
    if([_dm hasConnectivity])
    {
        [_dm fetchCentersForController:self];
    }
    else
    {
        [self pushErrorMessage:NSLocalizedString(@"nointernetconnection", nil)];
    }
    CAGradientLayer *bgLayer = [BackgroundLayer blueGradient];
    bgLayer.frame = self.view.bounds;
    [self.view.layer insertSublayer:bgLayer atIndex:0];

    _titleBackground = [[UIView alloc]initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, 44)];
    _titleBackground.backgroundColor = [GColor blueColor];
    [self.view addSubview:_titleBackground];

    _lblTitle = [[UILabel alloc]initWithFrame:CGRectMake(0, 0, self.view.frame.size.width - 10, 44)];
    _lblTitle.textAlignment = NSTextAlignmentRight;
    _lblTitle.textColor = [GColor whiteColor];
    _lblTitle.text = NSLocalizedString(@"bioscoopkeuze", nil);
    [self.view addSubview:_lblTitle];


    _btnGaVerder = [[UIButton alloc]initWithFrame:CGRectMake(0, self.view.frame.size.height - 54, self.view.frame.size.width, 54)];
    [_btnGaVerder setTitle:NSLocalizedString(@"gaverder", nil) forState:UIControlStateNormal];
    _btnGaVerder.titleLabel.font = [_btnGaVerder.titleLabel.font fontWithSize:12];
    _btnGaVerder.backgroundColor = [GColor blueColor];
    [_btnGaVerder setTitleColor:[GColor whiteColor] forState:UIControlStateNormal];
    [_btnGaVerder setShowsTouchWhenHighlighted:YES];
    [_btnGaVerder addTarget:self action:@selector(gaVerder) forControlEvents:UIControlEventTouchUpInside];

    _myPickerView = [[UIPickerView alloc]initWithFrame:CGRectMake(0, 44, self.view.frame.size.width, 200)];



}

-(void)showLoading
{
    NSLog(@"shows loading");
    _indicator = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];
    CGPoint cntr = self.view.center;
    _indicator.center = cntr;
    [_indicator startAnimating];
    [self.view addSubview:_indicator];


}


-(void)hideLoading
{
    NSLog(@"hides loading");
    [_indicator removeFromSuperview];
    _indicator = nil;

}

-(void)pushData:(NSArray *)data
{
    [self.view addSubview:_btnGaVerder];
    [self.view addSubview:_myPickerView];
    _centers = data;
    _myPickerView.delegate = self;
    _myPickerView.dataSource = self;


    _dm = [[DataManager alloc]init];
    GSettings* settings = [_dm loadSettings];

    if(settings == nil)
    {
        settings = [[GSettings alloc]init];
        settings.chosenCenter = [_centers objectAtIndex:0];
        settings.loadedCenter = [_centers objectAtIndex:0];
        _center = settings.chosenCenter;
        settings.notificationsEnabled = YES;
        [self changeAddressLines];
    }

    /*if(settings != nil)
     {
     GCenter* loaded = settings.loadedCenter;

     int i = 0;
     BOOL found = NO;

     while(i < [_centers count] && !found)
     {
     GCenter* center = (GCenter*)[_centers objectAtIndex:i];
     if(settings.loadedCenter.iD == center.iD)
     {
     _center = center;
     settings.chosenCenter = center;
     [_dm storeSettings:settings];
     found = YES;
     }

     i++;
     }
     //[self.myPickerView selectRow:i-1 inComponent:0 animated:NO];

     loaded = nil;
     [self changeAddressLines];

     }
     */
}

-(void) pushErrorMessage: (NSString*) errorMessage
{
    _alert = [[UIAlertView alloc] initWithTitle:NSLocalizedString(@"fout", nil) message:errorMessage delegate:self cancelButtonTitle:@"Ok" otherButtonTitles:nil];
    _alert.delegate = self;
    [_alert show];

}

- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
{
    if(buttonIndex == 0)
    {
        if(self.navigationController != nil)
        {
            [self.navigationController popViewControllerAnimated:YES];
        }
        else
        {
            //[self initializeData];
        }


    }

}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}



-(void)viewWillDisappear:(BOOL)animated
{
    [_dm cancelCenterRequest];
    /*if(self.tabBarController != nil)
     {
     dm = [[DataManager alloc]init];
     settings = [dm loadSettings];

     if([dm hasConnectivity])
     {
     settings.lastUpdated = nil;
     [dm storeSettings:settings];

     }

     if(settings.loadedCenter.centerCode != settings.chosenCenter.centerCode)
     {
     UIStoryboard *mystoryboard = [UIStoryboard storyboardWithName:@"Main" bundle:nil];
     SplashScreenController *controller =  [mystoryboard instantiateViewControllerWithIdentifier:@"root"];
     [self presentViewController:controller animated:YES completion:nil];
     }


     dm = nil;
     settings = nil;

     }
     */
}

-(void)gaVerder
{


    _dm = [[DataManager alloc]init];
    GSettings* settings = [_dm loadSettings];

    if(settings == nil)
    {
        settings = [[GSettings alloc]init];
        settings.notificationsEnabled = YES;
    }
    if(_center != nil)
    {
        settings.chosenCenter = _center;
    }
    [_dm storeSettings:settings];
    [_mapView removeFromSuperview];
    _mapView = nil;
    _titleBackground = nil;
    _lblTitle = nil;
    _btnGaVerder = nil;
    _myPickerView = nil;
    _point = nil;
    _indicator = nil;
    _alert = nil;
    _centers = nil;
    _adresLine = nil;
    _cityLine = nil;
    _center = nil;
    _dm = nil;


    [self.presentingViewController dismissViewControllerAnimated:NO completion:^{}];
    //DEZE BLIJFT HELAAS IN HET GEHEUGEN HANGEN... GEEN OPLOSSING GEVONDEN

    //[self.navigationController popViewControllerAnimated:NO];
}

//PICKERVIEWDELEGATE EN DATASOURCE

// returns the number of 'columns' to display.
- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
{
    return 1;
}

// returns the # of rows in each component..
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
{
    return [_centers count];
}

- (UILabel *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view
{
    GCenter* center = (GCenter*)[_centers objectAtIndex:row];
    NSString* string = center.name;
    UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, pickerView.frame.size.width, 44)];
    label.textColor = [GColor blueColor];
    label.font = [label.font fontWithSize:18];
    label.text = string;
    label.textAlignment = NSTextAlignmentCenter;
    return label;

}

- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
{
    _center = (GCenter*)[_centers objectAtIndex:row];

    [self changeAddressLines];

}


-(void)changeAddressLines
{
    if (_mapView != nil)
    {
        [_mapView removeAnnotation:_point];
    }

    [_adresLine removeFromSuperview];
    [_cityLine removeFromSuperview];
    _adresLine = nil;
    _cityLine = nil;



    CGRect rctAdres = CGRectMake(0, _myPickerView.frame.origin.y + _myPickerView.frame.size.height -10, self.view.frame.size.width, 20);
    _adresLine = [[UILabel alloc]initWithFrame:rctAdres];
    _adresLine.textAlignment = NSTextAlignmentCenter;
    _adresLine.textColor = [GColor greyColor];
    _adresLine.text = _center.street;

    CGRect rctCity = CGRectMake(0, rctAdres.origin.y + rctAdres.size.height, self.view.frame.size.width, 20);
    _cityLine = [[UILabel alloc]initWithFrame:rctCity];
    _cityLine.textAlignment = NSTextAlignmentCenter;
    _cityLine.textColor = [GColor greyColor];
    _cityLine.font = [_cityLine.font fontWithSize:14];
    _cityLine.text = _center.city;
    [self.view addSubview:_adresLine];
    [self.view addSubview:_cityLine];

    if(_mapView == nil)
    {

        double height;

        height = _btnGaVerder.frame.origin.y - _cityLine.frame.origin.y - _cityLine.frame.size.height;


        CGRect mapRect = CGRectMake(0, _cityLine.frame.origin.y+3 + _cityLine.frame.size.height, self.view.frame.size.width, height);
        _mapView = [[MKMapView alloc]initWithFrame:mapRect];
        [self.view addSubview:_mapView];
    }

    CLLocationCoordinate2D punt;
    punt.latitude = _center.latitude;
    punt.longitude =  _center.longitude;
    _point = [[MKPointAnnotation alloc] init];
    [_point setCoordinate:punt];
    _mapView.centerCoordinate = punt;
    _point.title = _center.name;
    [_mapView addAnnotation:_point];
    [_mapView setCenterCoordinate:punt animated:YES];
    MKCoordinateRegion theRegion = _mapView.region;
    theRegion.span.longitudeDelta = 0.005;
    theRegion.span.latitudeDelta = 0.005;
    [_mapView setRegion:theRegion animated:YES];



}




@end

最佳答案

就我而言，情况要复杂一些。我没有任何对我的 View Controller 具有强引用的变量，并且我的 View Controller 不是此类本身包含的任何属性/变量的强委托(delegate)。经过一番思考和尝试，我发现我的问题是由接口(interface)中定义的 NSTimer 对象引起的。定时器对象本身是不可重复的，但是它调用的方法最后会再次调度定时器，你可以想象会再次引用我 View Controller 中定义的这个方法，从而造成循环引用。为了打破这个循环，我必须在关闭 View Controller 之前使计时器无效。

总而言之，这些是 View Controller 在被解除后可以被阻止解除分配的情况:

  1. View Controller 被一些外部对象强引用；
  2. View Controller 是一个强委托(delegate)，由 View Controller 本身定义的某个对象引用
  3. dismissViewControllerAnimated:completion: block 可能引用自身或者它有一些其他代码块可能导致循环引用
  4. View Controller 有 NSTimer 对象，它可以调用一些重新安排计时器的方法

可能还有更多，但希望我们可以通过上述案例捕获很多案例。

关于ios - dismissViewControllerAnimated 不会释放 viewcontroller，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/25245360/

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