在我的应用程序中，有某些视图控制器，在 iPad（或更具体地说，常规水平尺寸类别）上将它们呈现为弹出窗口是有意义的，但在 iPhone（或紧凑水平尺寸类别）上则有意义将它们推入导航堆栈。有没有一种优雅的方式来支持这一点？默认情况下，如果我使用“Present as Popover”segue，它将在 iPhone 上以模态方式显示，这不是我想要的。
我找到了一种方法来获得我想要的行为，但它很丑陋并且似乎容易出错。我根据我当前所处的尺寸类别在两种不同的 Segue 之间进行选择。为了支持 iOS 9 多任务处理，我实现了
[UIViewController willTransitionToTraitCollection:withTransitionCoordinator]似乎应该有一些简单的方法来实现自定义 Segue 来处理这个问题，或者某种自定义自适应演示控制器，但我无法理解它。有人成功做到过吗？
据我来说这是最简单的方法，
第 1 步： 创建从一个控制器到另一个控制器的两个 Segue。
第2步：将一个segue的segue属性设置为另一个segue的push和popover
第3步：现在根据您的要求调用执行segue，即iPad或iPhone
这是示例代码
示例代码 注意：将 bool 条件更改为 false 以检查
didSelectRowAtIndexPath这就是我最终构建的内容。我对此不太满意，这就是为什么我直到现在才发布它。它不支持两个 segues 来查看具有相同类的控制器，并且它要求您自己跟踪弹出窗口的源矩形和源视图。但也许对其他人来说这将是一个很好的起点。
PushPopoverSegue.swift
import UIKit
class PushPopoverSegue: UIStoryboardSegue {
var sourceBarButtonItem: UIBarButtonItem!
var permittedArrowDirections: UIPopoverArrowDirection = .Any
override func perform() {
assert( self.sourceViewController.navigationController != nil )
assert( self.sourceBarButtonItem != nil )
if self.sourceViewController.traitCollection.horizontalSizeClass == .Compact {
self.sourceViewController.navigationController!.pushViewController(self.destinationViewController, animated: true)
}
else {
let navigationController = UINavigationController(rootViewController: self.destinationViewController)
let popover = UIPopoverController(contentViewController: navigationController)
popover.presentPopoverFromBarButtonItem(self.sourceBarButtonItem, permittedArrowDirections: self.permittedArrowDirections, animated: true)
}
}
}
UIViewController+PushPopoverTransition.h
#import <UIKit/UIKit.h>
@interface UIViewController (PushPopoverTransition)
- (void) transitionPushPopoversToHorizontalSizeClass: (UIUserInterfaceSizeClass) sizeClass withMapping: (NSDictionary*) mapping;
@end
UIViewController+PushPopoverTransition.m
#import "UIViewController+PushPopoverTransition.h"
@implementation UIViewController (PushPopoverTransition)
- (void) transitionPushPopoversToHorizontalSizeClass: (UIUserInterfaceSizeClass) sizeClass withMapping: (NSDictionary*) mapping
{
if ( sizeClass == UIUserInterfaceSizeClassCompact )
{
if ( self.presentedViewController == nil )
return;
NSParameterAssert( [self.presentedViewController isKindOfClass:[UINavigationController class]] );
UINavigationController* navigationController = (UINavigationController*) self.presentedViewController;
NSArray* viewControllers = navigationController.viewControllers;
UIViewController* topOfStack = viewControllers[0];
if ( [mapping.allKeys containsObject:NSStringFromClass( [topOfStack class] ) ] )
{
[self.presentedViewController dismissViewControllerAnimated:NO completion:^{
for ( UIViewController* viewController in viewControllers )
[self.navigationController pushViewController:viewController animated:NO];
}];
}
}
else if ( sizeClass == UIUserInterfaceSizeClassRegular )
{
NSUInteger indexOfSelf = [self.navigationController.viewControllers indexOfObject:self];
if ( indexOfSelf < self.navigationController.viewControllers.count - 1 )
{
UIViewController* topOfStack = self.navigationController.viewControllers[indexOfSelf + 1];
if ( [mapping.allKeys containsObject:NSStringFromClass( [topOfStack class] )] )
{
NSArray* poppedControllers = [self.navigationController popToViewController:self animated:NO];
UINavigationController* navigationController = [[UINavigationController alloc] init];
navigationController.modalPresentationStyle = UIModalPresentationPopover;
navigationController.viewControllers = poppedControllers;
id popoverSource = mapping[NSStringFromClass( [topOfStack class] )];
if ( [popoverSource isKindOfClass:[UIBarButtonItem class]] )
{
navigationController.popoverPresentationController.barButtonItem = popoverSource;
}
else if ( [popoverSource isKindOfClass:[NSArray class]] )
{
NSArray* popoverSourceArray = (NSArray*) popoverSource;
NSParameterAssert(popoverSourceArray.count == 2);
UIView* sourceView = popoverSourceArray[0];
CGRect sourceRect = [(NSValue*) popoverSourceArray[1] CGRectValue];
navigationController.popoverPresentationController.sourceView = sourceView;
navigationController.popoverPresentationController.sourceRect = sourceRect;
}
[self presentViewController:navigationController animated:NO completion:nil];
}
}
}
}
@end
用法示例
在界面生成器中创建一个segue，并将其“Kind”设置为“Custom”，并将其“Class”设置为
PushPopoverSegueViewController.m
- (void) prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
((PushPopoverSegue*) segue).sourceView = /* source view */;
((PushPopoverSegue*) segue).sourceRect = /* source rect */;
}
-(void) willTransitionToTraitCollection:(UITraitCollection *)newCollection withTransitionCoordinator:(id<UIViewControllerTransitionCoordinator>)coordinator
{
if ( newCollection.horizontalSizeClass == UIUserInterfaceSizeClassUnspecified )
return;
[self transitionPushPopoversToHorizontalSizeClass:newCollection.horizontalSizeClass withMapping:@{
@"MyDestinationViewController": @[ /* source view */,
[NSValue valueWithCGRect:/* source rect*/] ]
}];
}
对于 iOS 17，我只是在呈现视图控制器中执行此操作：
- (void)presentViewController:(UIViewController *)viewControllerToPresent animated:(BOOL)animated completion:(void (^)(void))completion {
if ( UIDevice.currentDevice.userInterfaceIdiom != UIUserInterfaceIdiomPad )
[self.navigationController pushViewController:viewControllerToPresent animated:animated];
else
[super presentViewController:viewControllerToPresent animated:animated completion:completion];
}
似乎有效；不确定这在早期的 SDK 版本中是否可行。