Question

我有一个UINavigationController并且我试图在每个UIViewController时从内存释放一旦另一个在堆栈顶部。我将viewControllers的{{1}}属性分配给新UINavigationController，然后将其弹出。这样我在堆栈中总是只有一个UIViewController。但是，每次创建新UIViewController时，内存都会不断累加。调用Dealloc，但内存使用情况保持不变。

您可以下载示例项目HERE

FirstViewController.h

UIViewController

FirstViewController.m

#import "SecondViewController.h"

@interface FirstViewController : UIViewController

-(IBAction)goToSecond:(id)sender;

@end

SecondViewController.h

#import "FirstViewController.h"

@interface FirstViewController ()

@end

@implementation FirstViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    NSLog(@"%@", self.navigationController.viewControllers);

}

-(void)goToSecond:(id)sender{

    SecondViewController *secondVC = [[SecondViewController alloc]init];
    [self.navigationController setViewControllers:@[secondVC]];
    [self.navigationController popViewControllerAnimated:NO];
}

-(void)dealloc{

    NSLog(@"FirstVC dealloc");
}
@end

SecondViewController.m

#import "FirstViewController.h"

@interface SecondViewController : UIViewController

-(IBAction)goToFirst:(id)sender;

@end

Answer 1

不应按预期使用导航控制器。您应该调用pushViewController和popViewController来显示/解除您的viewControllers。如果您遇到内存问题，请尝试在didReceiveMemoryWarning回拨

中释放内存

Answer 2

我不确定uinavigationcontroller的好处，但无论如何你可以在你的uiviewcontrollers .m上添加这个片段

-(void)viewDidAppear:(BOOL)animated{
    [super viewDidAppear:animated];    
    if (self.navigationController.viewControllers.count > 1) {
        NSMutableArray *newViewControllers = [NSMutableArray arrayWithArray:self.navigationController.viewControllers];
        [newViewControllers removeObject:[controllers objectAtIndex:1]];
        self.navigationController.viewControllers = newViewControllers;
    }
}

而不是

[self.navigationController setViewControllers:@[firstVC]];
[self.navigationController popViewControllerAnimated:NO];

你可以设置

[self.navigationController pushViewController:[[FirstViewController alloc] init] animated:NO];

Answer 3

您正在使用pop进一步，但如果您想转到下一个push，则需要使用ViewController。

-(void)goToSecond:(id)sender{
    SecondViewController *secondVC = [[SecondViewController alloc]init];
    [ self.navigationController pushViewController:secondVC animated:YES];
}

在SecondViewController回到FirstViewController，你应该使用pop

-(void)backToController
{
    [self.navigationController popViewControllerAnimated:YES];
}

在你的情况下

-(void)goToFirst:(id)sender
 {
        [self.navigationController popViewControllerAnimated:YES];
 }

Answer 4

我上传了一个简单的应用程序到GitHub，我在评论中讨论了假导航栏，希望它有助于满足您的需求：https://github.com/yosihashamen/HelpersApps

要确保您必须始终保持“BaseViewController”处于活动状态。

Answer 5

我的意思是这样的。

在FirstViewController使用presentViewController代替push向UINavigationController添加新SecondViewController

-(void)goToSecond:(id)sender{
    SecondViewController *secondVC = [[SecondViewController alloc]init]; 
    UINavigationController *nav = [[UINavigationController alloc] initWithRootViewController:secondVC];
    [self presentViewController:nav animated:YES completion:NIL];

}

在SecondViewController中添加UIBarButtonItem到Navigation bar

UIBarButtonItem *backButton = [[UIBarButtonItem alloc] initWithTitle:@"Back" style:UIBarButtonItemStyleDone target:nil action:@selector(goToFirst:)];
self.navigationItem.backBarButtonItem = backButton;

并实施解雇方法。

-(void)goToFirst:(id)sender
 {
    [self dismissViewControllerAnimated:YES completion:NULL];
 }

Answer 6

试用setViewControllers:animated:

这允许您在UINavigationController堆栈上显式设置视图控制器，就像您正在做的那样，它将自动处理导航动画，而无需您调用popViewControllerAnimated:

如果你有一个多视图旅程，你需要摆脱到目前为止已经显示的屏幕，但保持导航动画（例如，发布时的应用程序演示），或者如果你想轻松推送多个立即查看导航堆栈上的控制器。

Apple doc：https://developer.apple.com/library/ios/documentation/uikit/reference/UINavigationController_Class/Reference/Reference.html#jumpTo_21

弹出时UIViewController不会从内存中释放

6 个答案: