设置:“VC1”使用 Root View Controller “VC2”创建“NavigationVC”，并使用呈现样式 UIModalPresentationFormSheet 以模态方式呈现它。 “VC2”以正确的尺寸显示在屏幕中间的导航 Controller 内。

问题:当我继续将 View Controller 推送到模态 NavVC 时，我希望它们能够调整大小。推送的每个 View Controller 中我的 preferredContentSize 的 NSLog 验证我的约束是否正确并且大小实际上不同。但是，我已经进行了广泛的实验，但还没有弄清楚如何在呈现模态后更改模态的大小。

@implementation VC1()

- (void) viewDidLoad{
    VC1* vc1 = [self getNextVC];
    NavVC* navVC = [[UINavigationViewController alloc] initWithRootViewController:vc1];
    [navVC setModalPresentationStyle:UIModalPresentationFormSheet];
    [self presentViewController:navVC animated:YES completion:nil];
}

@end

@implementation NavVC()

- (CGSize) preferredContentSize{
    CGSize size = [[self topViewController] preferredContentSize];
    return size;
}

@end


@implementation VC2()

- (CGSize) preferredContentSize{
    CGSize size = [[self view] systemLayoutSizeFittingSize:UILayoutFittingCompressedSize];
    return size;
}

@end

最佳答案

我花了一些时间来处理同样的问题。在 iOS8 的模态导航 Controller 上推送 View Controller 导致 View Controller 与 Root View Controller 具有相同的大小，而对于 iOS7，第二个 View Controller 具有模态表单的默认大小(540.f，620.f) .到目前为止，我能想到的唯一可行的解​​决方案，适用于 iOS7 和 iOS8，如下所示:

ViewController1.m

@interface ViewController1 ()  

@end

@implementation ViewController1

-(void)viewWillAppear:(BOOL)animated
{
    [super viewWillAppear:animated];
    self.navigationController.view.superview.bounds = CGRectMake(0, 0, VC1_WIDTH, VC1_HEIGHT);
}

- (void)nextTapped:(id)sender {
    ViewController2 *vc2 = [storyboard instantiateViewControllerWithIdentifier:@"ViewController2"];
    [self.navigationController pushViewController:vc2 animated:NO];
    // call after push
    self.navigationController.view.superview.bounds = CGRectMake(0, 0,VC2_WIDTH,VC2_HEIGHT);
}

@end

呈现 ViewController1:

    ViewController1 *vc1 = [storyboard instantiateViewControllerWithIdentifier:@"ViewController1"];
    UINavigationController *navVC = [[UINavigationController alloc] initWithRootViewController:vc1];
    navVC.modalPresentationStyle = UIModalPresentationFormSheet;
    [self presentViewController:navVC animated:NO completion:nil];

ViewController2.m

#import "ViewController2.h”

@interface ViewController2 ()

@end

@implementation ViewController2

-(void)viewWillAppear:(BOOL)animated
{
    [super viewWillAppear:animated];
    self.navigationController.view.superview.bounds = CGRectMake(0, 0, VC2_WIDTH, VC2_HEIGHT);
}

- (void)nextTapped:(id)sender {
    ViewController3 *vc3 = [storyboard instantiateViewControllerWithIdentifier:@"ViewController3”];
    [self.navigationController pushViewController:vc3 animated:NO];
    self.navigationController.view.superview.bounds = CGRectMake(0, 0,VC3_WIDTH,VC3_HEIGHT);
}

- (void)backTapped:(id)sender {
    self.navigationController.view.superview.bounds = CGRectMake(0, 0,VC1_WIDTH,VC1_HEIGHT);
    [self.navigationController popViewControllerAnimated:NO];
}

@end

ViewController3.m

#import "ViewController3.h”

@interface ViewController3 ()

@end

@implementation ViewController3

-(void)viewWillAppear:(BOOL)animated
{
    [super viewWillAppear:animated];
    self.navigationController.view.superview.bounds = CGRectMake(0, 0, VC3_WIDTH, VC3_HEIGHT);
}

- (void)backTapped:(id)sender {
    self.navigationController.view.superview.bounds = CGRectMake(0, 0,VC2_WIDTH,VC2_HEIGHT);
    [self.navigationController popViewControllerAnimated:NO];
}

@end

请注意，如果您要将文本输入字段添加到那些推送到模态导航 Controller 上的 View Controller ，对于 iOS8，键盘显示和关闭将自动将它们调整为错误的大小。不幸的是，我仍然没有正确解决这个问题。

关于ios - 在推送每个新 View Controller 时调整导航 Controller 的大小以模态方式呈现 UIModalPresentationFormSheet，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/28053811/