本文介绍了当iPad上出现带有iOS8的键盘时，移动一个模态呈现的UIViewController的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我在UINavigationController中有一个UIViewController，在带有iOS8的iPad上进行模态显示。我正在使用
I've got a UIViewController inside of a UINavigationController, presented modally on an iPad with iOS8. I'm using
self.myNavController.modalPresentationStyle = UIModalPresentationFormSheet;
在我的视图控制器中，我有一个文本字段。由于视图控制器的UI设计，当用户点击文本字段并出现键盘时，我需要在屏幕上向上移动视图控制器。在iOS7上，我将动画更改为
Within my view controller, I have a text field. Because of the UI design of the view controller, when the user taps in the text field, and the keyboard appears, I need to move the view controller up on the screen. On iOS7, I had been animating a change to
self.myNavController.view.superview.frame.origin
以便向上移动视图控制器，然后向下移动。这很好用。
in order to move the view controller up, and back down. This worked well.
然而，在iOS8上，这已经不再适用了。事实上，奇怪的是，行为是视图控制器稍微移动向下然后备份（所有当我分配一个带有较小的值Y坐标。）
However, on iOS8, this is no longer working. In fact, oddly, the behavior is for the view controller to move slightly down and then back up (all when I'm assigning self.myNavController.view.superview.frame.origin a CGPoint with a smaller valued Y coordinate).
最初，我正在根据这个SO问题给出的建议
Originally, I was working from a suggestion given in this SO question Resize ModalViewController and position it at center in iOS 7
我最近尝试了以
给出的建议，但收效甚微。实际上，随着转换思想的回答，我至少可以让视图控制器向正确的方向移动（即向上），但它不会停留在那里。它会很快回落。
And I recently tried the suggestion given inMoving dialog up when keyboard present works except when ipad is turned around but to little avail. Actually, with the transform idea in an answer there, I can at least get the view controller to move in the right direction (i.e., up), but it doesn't stay there. It quickly goes back down.
想法？
推荐答案
我们' ll，我现在非常激动。我已经弄清楚了。这可以使用新的iOS8 UIPresentationController来解决。我将在下面给出一些示例代码。并尝试稍后链接到一个工作项目zip文件。
We'll, I'm pretty stoked now. I've figured this out. This can be solved using the new, iOS8 UIPresentationController. I'll give some sample code below. And try to link in a working project zip file later.
第一个视图控制器是示例应用程序的根视图控制器。 ChangeFrameTransitioningDelegate的代码如下。 Dialog只是一个空视图控制器类。
The first view controller is the root view controller of the example app. Code for the ChangeFrameTransitioningDelegate follows below. "Dialog" is just an empty view controller class.
//
// ViewController.m
// TestPresentationController
//
// Created by Christopher Prince on 9/21/14.
// Copyright (c) 2014 Spastic Muffin, LLC. Use at your own discretion.
//
#import "ViewController.h"
#import "ChangeFrameTransitioningDelegate.h"
#import "Dialog.h"
@interface ViewController ()
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
}
- (void) viewDidAppear:(BOOL)animated;
{
[super viewDidAppear:animated];
ChangeFrameTransitioningDelegate *td = [ChangeFrameTransitioningDelegate new];
td.viewControllerFrame = CGRectMake(100, 0, 100, 100);
Dialog *d = [Dialog new];
// Just to make the VC stand out.
d.view.backgroundColor = [UIColor greenColor];
// Need to make this custom in order to have the presentationControllerForPresentedViewController method of the transitioning delegate called.
d.modalPresentationStyle = UIModalPresentationCustom;
d.modalTransitionStyle = UIModalTransitionStyleCoverVertical;
d.transitioningDelegate = td;
[self presentViewController:d animated:YES completion:^{
// Any time after the view controller is presented you can change the
// viewControllerFrame property to change the size and/or position of the
// presented view controller.
[UIView animateWithDuration:0.5 animations:^{
td.viewControllerFrame = CGRectMake(100, 800, 100, 100);
}];
}];
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
@end
//
// ChangeFrameTransitioningDelegate.h
// TestPresentationController
//
// Created by Christopher Prince on 9/21/14.
// Copyright (c) 2014 Spastic Muffin, LLC. Use at your own discretion.
//
// For iOS8 and later, use this to change the size/position of a view controller after it has been presented. See TextPresentationController example.
#import <Foundation/Foundation.h>
#import <UIKit/UIKit.h>
@interface ChangeFrameTransitioningDelegate : NSObject<UIViewControllerTransitioningDelegate>
// This is the size and position that the PresentationController used by this class will use when its frameOfPresentedViewInContainerView method is called. So, this is the size and position that your view controller will have.
@property (nonatomic) CGRect viewControllerFrame;
@end
//
// ChangeFrameTransitioningDelegate.m
// TestPresentationController
//
// Created by Christopher Prince on 9/21/14.
// Copyright (c) 2014 Spastic Muffin, LLC. Use at your own discretion.
//
// Some help from http://stackoverflow.com/questions/25903412/editing-bounds-of-uiview-when-presenting-hides-keyboard-in-ios-8
// http://stackoverflow.com/questions/25811199/ios-8-change-the-size-of-presented-modal-view-controller
// Some code from https://developer.apple.com/devcenter/download.action?path=/wwdc_2014/wwdc_2014_sample_code/lookinsidepresentationcontrollersadaptivityandcustomanimatorobjects.zip (though, beware, this example doesn't work straight out of the box).
// And see http://stackoverflow.com/questions/25957343/moving-a-modally-presented-uiviewcontroller-up-when-keyboard-appears-on-ipad-wit
#ifndef SPASLogDetail
#define SPASLogDetail NSLog
#endif
#import "ChangeFrameTransitioningDelegate.h"
@interface PresentationController : UIPresentationController
{
UIView *_dimmingView;
}
// This is the size and position that the PresentationController will use when its frameOfPresentedViewInContainerView method is called.
@property (nonatomic) CGRect currentFrame;
@end
@implementation PresentationController
- (instancetype)initWithPresentedViewController:(UIViewController *)presentedViewController presentingViewController:(UIViewController *)presentingViewController;
{
self = [super initWithPresentedViewController:presentedViewController presentingViewController:presentingViewController];
// Some random default size.
self.currentFrame = CGRectMake(0, 0, 100, 100);
[self prepareDimmingView];
return self;
}
// 4/22/15; Added, for rotation.
- (void) viewWillTransitionToSize:(CGSize)size withTransitionCoordinator:(id<UIViewControllerTransitionCoordinator>)coordinator;
{
CGSize increasedSize = size;
// 4/22/15; I'm getting some odd effects: In a rotation transition from landscape to portrait, the RHS goes white momentarily, and from portrait to landscape, the bottom goes white momentarily. A hack, but increase the size of the dimming view to get around this.
increasedSize.width *= 1.5;
increasedSize.height *= 1.5;
_dimmingView.frameSize = increasedSize;
// There appears to be no transitionCoordinator available for this "transition". Therefore using the regular UIView animation, below.
/*
if([self.presentedViewController transitionCoordinator])
{
[[self.presentedViewController transitionCoordinator] animateAlongsideTransition:^(id<UIViewControllerTransitionCoordinatorContext> context) {
recenterViewController();
} completion:nil];
}
else
{
recenterViewController();
}*/
// 4/23/15; See [1]. Given that I've turned off resizing with the autoresizingMask, this has messed up the repositioning of the (x, y) coordinate of the presentedViewController. Make up for that here.
[UIView animateWithDuration: coordinator.transitionDuration animations:^{
// I'm assuming the size here refers to the entire window.
CGPoint center = CGPointMake(size.width/2.0, size.height/2.0);
self.presentedViewController.view.center = center;
} completion:nil];
}
- (void)presentationTransitionWillBegin
{
UIView* containerView = [self containerView];
// 4/23/15; So, this seems to be related to my modal view resizing problem. When I disable autoresizesSubviews, I stop the resizing during the rotation. HOWEVER, this is at the price of two additional problems: (a) the (x, y) coordinate of the modal stops being changed during the rotation, and (b) the animation of the background (_dimmingView?) starts looking funky during the rotation. WHICH makes sense. The containerView size is the full window.
//containerView.autoresizesSubviews = NO;
UIViewController* presentedViewController = [self presentedViewController];
// [1] 4/23/15; This is better. The _dimmingView animation is preserved. The (x, y) position of the presentedViewController, however isn't right after the rotation.
presentedViewController.view.autoresizingMask = UIViewAutoresizingNone;
[_dimmingView setFrame:[containerView bounds]];
[_dimmingView setAlpha:0.0];
[containerView insertSubview:_dimmingView atIndex:0];
void (^setAlpha)() = ^{
[_dimmingView setAlpha:1.0];
};
if([presentedViewController transitionCoordinator])
{
[[presentedViewController transitionCoordinator] animateAlongsideTransition:^(id<UIViewControllerTransitionCoordinatorContext> context) {
setAlpha();
} completion:nil];
}
else
{
setAlpha();
}
}
- (void)dismissalTransitionWillBegin
{
void (^resetAlpha)() = ^{
[_dimmingView setAlpha:0.0];
};
if([[self presentedViewController] transitionCoordinator])
{
[[[self presentedViewController] transitionCoordinator] animateAlongsideTransition:^(id<UIViewControllerTransitionCoordinatorContext> context) {
resetAlpha();
} completion:nil];
}
else
{
resetAlpha();
}
}
- (CGRect)frameOfPresentedViewInContainerView
{
SPASLogDetail(@"frameOfPresentedViewInContainerView: %@", NSStringFromCGRect(self.currentFrame));
return self.currentFrame;
}
- (void) setCurrentFrame:(CGRect)currentFrame
{
_currentFrame = currentFrame;
// This is the important part for changing the frame of the presented view controller *after* the view is presented. For some odd reason, its not right to change the frame of the containerView.
self.presentedView.frame = currentFrame;
}
- (void) containerViewWillLayoutSubviews;
{
SPASLogDetail(@"containerViewWillLayoutSubviews");
}
- (void)prepareDimmingView
{
_dimmingView = [[UIView alloc] init];
[_dimmingView setBackgroundColor:[UIColor colorWithWhite:0.0 alpha:0.4]];
[_dimmingView setAlpha:0.0];
//UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(dimmingViewTapped:)];
//[_dimmingView addGestureRecognizer:tap];
}
/*
- (void)dimmingViewTapped:(UIGestureRecognizer *)gesture
{
if([gesture state] == UIGestureRecognizerStateRecognized)
{
[[self presentingViewController] dismissViewControllerAnimated:YES completion:NULL];
}
}*/
@end
@interface ChangeFrameTransitioningDelegate()
@property (nonatomic, strong) PresentationController *presentationController;
@end
@implementation ChangeFrameTransitioningDelegate
- (instancetype) init;
{
self = [super init];
return self;
}
- (UIPresentationController *)presentationControllerForPresentedViewController:(UIViewController *)presented presentingViewController:(UIViewController *)presenting sourceViewController:(UIViewController *)source
{
self.presentationController = [[PresentationController alloc] initWithPresentedViewController:presented presentingViewController:presenting];
self.presentationController.currentFrame = self.viewControllerFrame;
return self.presentationController;
}
- (void) setViewControllerFrame:(CGRect)viewControllerFrame
{
_viewControllerFrame = viewControllerFrame;
self.presentationController.currentFrame = viewControllerFrame;
}
@end
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