在 iOS 8 中呈现隐藏键盘时编辑 UIView 的边界

Question

我将一个小的“登录”UIViewController 显示为具有自定义边界的 UIModalPresentationFormSheet。在viewWillLayoutSubviews 方法中，我将视图的大小更改为(300,250)。这在 iOS 5/6/7 中有效，但在 8 中不再有效。

当显示视图并点击UITextField 时，应用程序变得无响应（不冻结，只是不响应触摸）。几乎就像键盘出现但没有出现一样。委托方法被正确调用。如果我从viewWillLayoutSubviews 方法中删除self.view.superview.bounds = CGRectMake(0, 0, 300, 250);，键盘可以工作，但视图现在是全尺寸UIModalPresentationFormSheet 样式。

这只发生在 iOS 8 中，所以我只能假设它是键盘呈现方式以及我屏蔽/调整视图大小的方式的问题，但我不知道解决方案。

呈现 ViewController -

UserLoginViewController *loginVC = [[UserLoginViewController alloc] initWithNibName:@"UserLoginViewController" bundle:nil];
loginVC.modalPresentationStyle = UIModalPresentationFormSheet;
loginVC.delegate = self;
[self presentViewController:loginVC animated:YES completion:nil];

编辑视图边界 -

- (void)viewWillLayoutSubviews {

    [super viewWillLayoutSubviews];
    self.view.superview.layer.cornerRadius  = 10.0;
    self.view.superview.layer.masksToBounds = YES;
    self.view.superview.bounds = CGRectMake(0, 0, 300, 250);
}

Answer 1

在 iOS8 中你不应该在 viewWillLayoutSubviews 中改变 superview 的边界，因为它会导致无限循环。

编辑： 在 iOS8 属性中，preferredContentSize 效果很好。

您应该以这种方式更改您的代码：

  UserLoginViewController *loginVC = [[UserLoginViewController alloc] initWithNibName:@"UserLoginViewController" bundle:nil];
    loginVC.modalPresentationStyle = UIModalPresentationFormSheet;
    loginVC.delegate = self;
    if(IS_IOS8)
    {
        loginVC.preferredContentSize = CGSizeMake(300, 250);
    }
    [self presentViewController:loginVC animated:YES completion:nil];

编辑视图边界 -

 - (void)viewWillLayoutSubviews{
    [super viewWillLayoutSubviews];

    self.view.superview.layer.cornerRadius  = 10.0;
    self.view.superview.layer.masksToBounds = YES;

    if(!IS_IOS8)
    {
        self.view.superview.bounds = CGRectMake(0, 0, 300, 250);
    }
}

另一种为您提供更多自定义选项的方法是使用 UIPresentationController 和 UIViewControllerTransitioningDelegate。看看我下面的代码。

父视图控制器：

 _aboutViewController = [[AboutViewController alloc] init];
        _aboutViewController.modalPresentationStyle = UIModalPresentationFormSheet;
        if(IS_IOS8)
        {
            if(aboutTransitioningDelegate == nil)
            {
                aboutTransitioningDelegate = [[AboutTransitioningDelegate alloc] init];
            }
            _aboutViewController.transitioningDelegate = aboutTransitioningDelegate;
            _aboutViewController.modalPresentationStyle = UIModalPresentationCustom;
        }
        [self presentViewController:_aboutViewController animated:YES completion:nil];

AboutViewController.m

#import "AboutViewController.h"

@interface AboutViewController ()

@end

@implementation AboutViewController

- (void)viewWillLayoutSubviews{
    [super viewWillLayoutSubviews];

    if(IS_IOS8)
    {
        return;
    }
    CGSize displaySize = CGSizeMake(320, 462);

    self.view.superview.bounds = CGRectMake(0, 0, displaySize.width, displaySize.height);
}

@end

关于TransitioningDelegate.h：

@interface AboutTransitioningDelegate : NSObject <UIViewControllerTransitioningDelegate>

@end

关于TransitioningDelegate.m：

#import "AboutTransitioningDelegate.h"
#import "AboutPresentationController.h"
@implementation AboutTransitioningDelegate

-(UIPresentationController *)presentationControllerForPresentedViewController:(UIViewController *)presented presentingViewController:(UIViewController *)presenting sourceViewController:(UIViewController *)source
{
    return [[AboutPresentationController alloc] initWithPresentedViewController:presented presentingViewController:presenting];
}
@end

关于PresentationController.h

#import <UIKit/UIKit.h>

@interface AboutPresentationController : UIPresentationController

@end

关于PresentationController.m

#import "AboutPresentationController.h"

@implementation AboutPresentationController


-(CGRect)frameOfPresentedViewInContainerView
{
    CGSize displaySize = CGSizeMake(320, 462);

    if([[Config sharedInstance] latestVersionFromAppstoreInstalled])
    {
        displaySize = CGSizeMake(320, 416);
    }

    CGRect  r =  CGRectZero;
    r.size = displaySize;
    r.origin.y = self.containerView.bounds.size.height/2 - displaySize.height/2;
    r.origin.x = self.containerView.bounds.size.width/2 - displaySize.width/2;
    return r;

}
-(void)containerViewWillLayoutSubviews
{
    [super containerViewWillLayoutSubviews];
    self.presentedView.frame = [self frameOfPresentedViewInContainerView];
}

@end

项目名称-前缀.pch

#define IS_IOS8 ([[[UIDevice currentDevice] systemVersion] floatValue] >= 8)

Answer 2

调用containerViewWillLayoutSubviews()的最简单方法是调用：

containerView?.setNeedsLayout()