显示导航栏时 viewWillAppear 中的正确 self.view.frame

Posted 2023-03-12

【中文标题】显示导航栏时 viewWillAppear 中的正确 self.view.frame

【英文标题】：Proper self.view.frame in viewWillAppear while showing navigationBar

【发布时间】：2012-10-03 11:37:07

【问题描述】：

我在父视图控制器中显示navigationBar：

- (void)viewWillDisappear:(BOOL)animated

    [self.navigationController setNavigationBarHidden:NO animated:YES];
    [super viewWillDisappear:animated];

然后，在下一个视图控制器中

- (void)viewDidLoad

    /* ... */
    NSLog(@"%i, %g", self.navigationController.navigationBarHidden,
            self.view.frame.size.height);


- (void)viewWillAppear:(BOOL)animated

    /* ... */
    [super viewWillAppear:animated];
    NSLog(@"%i, %g", self.navigationController.navigationBarHidden, 
            self.view.frame.size.height);


- (void)viewWillLayoutSubviews

    NSLog(@"%i, %g", self.navigationController.navigationBarHidden, 
            self.view.frame.size.height);


- (void)viewDidAppear:(BOOL)animated

    NSLog(@"%i, %g", self.navigationController.navigationBarHidden, 
            self.view.frame.size.height);

输出：

-[viewDidLoad]: 1, 416
-[viewWillAppear:]: 0, 460
-[viewWillLayoutSubviews]: 0, 416
-[viewDidAppear:]: 0, 416

如您所见，viewWillAppear 出错了self.view.frame.size.height。可以使用viewWillLayoutSubviews，但它是在ios5中引入的。是否可以在 viewWillAppear 中获得适当的帧高度？

【问题讨论】：

为什么 460 错了？ 480-20（状态栏高度）= 460

抱歉，我正在显示导航栏；)

【参考方案1】：

这是迄今为止我得到的最佳解决方案：

- (void)viewWillAppear:(BOOL)animated

    /* recalculate frame size */
    CGSize size = [UIScreen mainScreen].bounds.size;
    UIApplication *application = [UIApplication sharedApplication];
    if (UIInterfaceOrientationIsLandscape(application.statusBarOrientation))
        size = CGSizeMake(size.height, size.width);
    if (!application.statusBarHidden)
        size.height -= MIN(application.statusBarFrame.size.width,
                           application.statusBarFrame.size.height);

    CGRect frame = self.view.frame;
    frame.size.height = size.height -
                        self.navigationController.navigationBar.frame.size.height;
    self.view.frame = frame;

    /* ... */