出现键盘时如何在iOS上调整UITextView的大小？

Question

UITextView 插入到UITabBarController 的标签中（在 iPhone 上）。

1. 用很多行填充UITextView。
2. 显示键盘以编辑文本。

发生了什么？键盘用光标隐藏了UITextView 的一半。结果无法编辑文本。

如何解决所有 Apple 移动设备（屏幕分辨率不同）的问题？非常感谢您的帮助！

Answer 1

以下代码达到了最好的结果。另外不要忘记将背景颜色设置为 UIView 并将 UITextView 放在其他顶部屏幕控件（例如 UITabBar）之前。

文本的最终编辑现在仍然不完美。你可以尝试改进。

FirstViewController.h:

@interface FirstViewController : UIViewController {
    IBOutlet UIBarButtonItem *buttonDone;
    IBOutlet UITextView *textView;
    UITabBarController* tabBarController; // set from superview in AppDelegate (MainWindow.xib)
}

@property (nonatomic, retain) UITabBarController* tabBarController;

FirstViewController.m:

@synthesize tabBarController;

- (void)viewDidAppear:(BOOL)animated
{
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillShown:) name:UIKeyboardWillShowNotification object:nil];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillHide:) name:UIKeyboardWillHideNotification object:nil];
}

- (void)viewWillDisappear:(BOOL)animated
{
    [[NSNotificationCenter defaultCenter] removeObserver:self];
}

- (void)moveTextViewForKeyboard:(NSNotification*)aNotification up:(BOOL)up {
    NSDictionary* userInfo = [aNotification userInfo];
    NSTimeInterval animationDuration;
    UIViewAnimationCurve animationCurve;
    CGRect keyboardEndFrame;

    [[userInfo objectForKey:UIKeyboardAnimationCurveUserInfoKey] getValue:&animationCurve];
    [[userInfo objectForKey:UIKeyboardAnimationDurationUserInfoKey] getValue:&animationDuration];
    [[userInfo objectForKey:UIKeyboardFrameEndUserInfoKey] getValue:&keyboardEndFrame];

    [UIView beginAnimations:nil context:nil];
    [UIView setAnimationDuration:animationDuration];
    [UIView setAnimationCurve:animationCurve];

    CGRect newFrame = textView.frame;
    CGRect keyboardFrame = [self.view convertRect:keyboardEndFrame toView:nil];
    keyboardFrame.size.height -= tabBarController.tabBar.frame.size.height;
    newFrame.size.height -= keyboardFrame.size.height * (up?1:-1);
    textView.frame = newFrame;

    [UIView commitAnimations];   
}

- (void)keyboardWillShown:(NSNotification*)aNotification
{
    buttonDone.enabled = true;
    [self moveTextViewForKeyboard:aNotification up:YES]; 
}

- (void)keyboardWillHide:(NSNotification*)aNotification
{
    buttonDone.enabled = false;
    [self moveTextViewForKeyboard:aNotification up:NO]; 
}

附：没有 stackoverflow 很难为 iOS 编写代码......

Answer 2

使用自动布局，处理起来要容易得多（前提是您了解自动布局）：

您无需尝试识别受影响的视图并调整其大小，只需为您的所有视图内容创建一个父框架。然后，如果 kbd 出现，您调整框架的大小，并且如果您正确设置了约束，视图将很好地重新排列其所有子视图。无需为此摆弄大量难以阅读的代码。

事实上，在similar question 中，我找到了指向此excellent tutorial 的有关此技术的链接。

Answer 3

我在尝试让我的文本视图在 iOS 7 和 iOS 8 以及新的 QuickType 功能下正确滚动和动画时遇到了几个问题。起初我专注于动画滚动视图插图，但 iOS 7 和 8 之间的行为不同，无法让它在两者上正常工作。

然后我意识到我可以通过只关注框架来简化事情，这对我来说可以使用更简单的代码。总结：

• 注册UIKeyboardDidChangeFrameNotification（这将在显示/隐藏 QuickType 时通知）。
• 算出你需要多少垂直空间来改变你的文本视图的框架。
• 动画帧大小变化。

以下是一些说明上述内容的代码：

- (void)viewDidLoad {
    [super viewDidLoad];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardDidChangeFrameWithNotification:) name:UIKeyboardDidChangeFrameNotification object:nil];
}

- (void)keyboardDidChangeFrameWithNotification:(NSNotification *)notification {
    CGFloat keyboardVerticalIncrease = [self keyboardVerticalIncreaseForNotification:notification];
    [self animateTextViewFrameForVerticalOffset:keyboardVerticalIncrease];
}

- (CGFloat)keyboardVerticalIncreaseForNotification:(NSNotification *)notification {
    CGFloat keyboardBeginY = [notification.userInfo[UIKeyboardFrameBeginUserInfoKey] CGRectValue].origin.y;
    CGFloat keyboardEndY = [notification.userInfo[UIKeyboardFrameEndUserInfoKey] CGRectValue].origin.y;
    CGFloat keyboardVerticalIncrease = keyboardBeginY - keyboardEndY;
    return keyboardVerticalIncrease;
}

- (void)animateTextViewFrameForVerticalOffset:(CGFloat)offset {
    CGFloat constant = self.bottomConstraint.constant;
    CGFloat newConstant = constant + offset;
    self.bottomConstraint.constant = newConstant;
    [self.view layoutIfNeeded];
    [UIView animateWithDuration:0.5 animations:^{
        [self.view layoutIfNeeded];
    }];
}

关于动画的简要说明。我使用了 Autolayout，所以我选择为文本视图的 NSAutoLayoutConstraint 设置动画，而不是直接为框架设置动画。为此，我在动画块内的 和 之前调用 [self.view layoutIfNeeded]。这是动画约束的正确方法。我找到了这个提示here。

Answer 4

值得注意的是，仅当设备处于纵向模式（而不是倒置）时，赞成的答案才有效，在其他模式下，边界会出错。我相信你可以通过使用边界来修复这个问题，但我无法让它工作，所以下面的调整对我有用：

- (void)moveTextViewForKeyboard:(NSNotification*)aNotification up:(BOOL)up {


NSDictionary* userInfo = [aNotification userInfo];
NSTimeInterval animationDuration;
UIViewAnimationCurve animationCurve;
CGRect keyboardEndFrame;

[[userInfo objectForKey:UIKeyboardAnimationCurveUserInfoKey] getValue:&animationCurve];
[[userInfo objectForKey:UIKeyboardAnimationDurationUserInfoKey] getValue:&animationDuration];
[[userInfo objectForKey:UIKeyboardFrameEndUserInfoKey] getValue:&keyboardEndFrame];


[UIView beginAnimations:nil context:nil];
[UIView setAnimationDuration:animationDuration];
[UIView setAnimationCurve:animationCurve];

CGRect newFrame = self.view.frame;

if (keyboardEndFrame.size.height >keyboardEndFrame.size.width)
{   //we must be in landscape
    if (keyboardEndFrame.origin.x==0)
    {   //upside down so need to flip origin
        newFrame.origin = CGPointMake(keyboardEndFrame.size.width, 0);
    }

    newFrame.size.width -= keyboardEndFrame.size.width * (up?1:-1);

} else
{   //in portrait
    if (keyboardEndFrame.origin.y==0)
    {
        //upside down so need to flip origin
        newFrame.origin = CGPointMake(0, keyboardEndFrame.size.height);
    }
    newFrame.size.height -= keyboardEndFrame.size.height * (up?1:-1);

}
self.view.frame = newFrame;

[UIView commitAnimations];



}

Answer 5

多年过去了，问题仍然存在。苹果绝对应该自己处理所有这些事情。但事实并非如此。这是基于官方 Apple 的 documentation 以及错误修复的新解决方案。它支持 iOS 8、iOS 9、inputAccessoryView 并为新版本的 iOS 和新设备做好准备。

/* Apple's solution to resize keyboard but with accessory view support */

- (void)keyboardDidShow:(NSNotification*)aNotification {
    NSDictionary* info = [aNotification userInfo];
    CGRect keyboardFrame = [[info objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue];
    double keyboardHeight = [[UIScreen mainScreen] bounds].size.height - keyboardFrame.origin.y;

    UIEdgeInsets contentInsets = UIEdgeInsetsMake(0.0, 0.0, keyboardHeight, 0.0);
    editor.contentInset = contentInsets;
    editor.scrollIndicatorInsets = contentInsets;
}

- (void)keyboardWillHide:(NSNotification*)aNotification {
    UIEdgeInsets contentInsets = UIEdgeInsetsZero;
    editor.contentInset = contentInsets;
    editor.scrollIndicatorInsets = contentInsets;

    // button to hide the keyboard
    buttonDone.enabled = false;
}

/* Fix issues with size classes and accessory view */

- (void)viewWillTransitionToSize:(CGSize)size withTransitionCoordinator:(id<UIViewControllerTransitionCoordinator>)coordinator {
    [super viewWillTransitionToSize:size withTransitionCoordinator:coordinator];
    // fix incorrect size of the inputAccessoryView when size class changed
    // willTransitionToTraitCollection and traitCollectionDidChange can't help us
    if (editor && editor.inputAccessoryView && !editor.inputAccessoryView.hidden) {
        [editor resignFirstResponder];
    }
}

/* Hide accessory view if a hardware keyboard is present */

#define gThresholdForHardwareKeyboardToolbar 160.f // it's minimum height of the software keyboard on iPhone 4 in landscape mode

- (bool)isExternalKeyboard:(NSNotification*)aNotification {
    NSDictionary* info = [aNotification userInfo];
    CGRect keyboardFrame = [[info objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue];
    double keyboardHeight = [[UIScreen mainScreen] bounds].size.height - keyboardFrame.origin.y;

    return keyboardHeight < gThresholdForHardwareKeyboardToolbar;
}

- (void)keyboardWillShow:(NSNotification*)aNotification {
    if ([self isExternalKeyboard:aNotification]) {
        // hardware keyboard is present
        if (editor && editor.inputAccessoryView) {
            editor.inputAccessoryView.hidden = true;
        }
    } else {
        // only on-screen keyboard
        if (editor && editor.inputAccessoryView) {
            editor.inputAccessoryView.hidden = false;
        }
    }

    // button to hide the keyboard
    buttonDone.enabled = true;
}

Answer 6

- (void)registerKeyboardNotifications
{
    [[NSNotificationCenter defaultCenter]
     addObserver:self
     selector:@selector(keyboardWillShow:)
     name:UIKeyboardDidShowNotification
     object:nil];

    [[NSNotificationCenter defaultCenter]
     addObserver:self
     selector:@selector(keyboardWillHide:)
     name:UIKeyboardWillHideNotification
     object:nil];
}

- (void)unregisterKeyboardNotifications
{
    [[NSNotificationCenter defaultCenter] removeObserver:self];
}

-(void) keyboardWillHide:(NSNotification *)note
{
   //adjust frame
}

-(void) keyboardWillShow:(NSNotification *)note
{
   //adjust frame 
}

在dealloc中也取消注册通知

- (void)unregisterKeyboardNotifications
{
    [[NSNotificationCenter defaultCenter] removeObserver:self];
}

Answer 7

首先在NSNotificationCenterdefaultCenter 中添加几个键盘方法

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillShow:) 
                                             name:UIKeyboardWillShowNotification object:self.view.window]; 

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillHide:) 
                                             name:UIKeyboardWillHideNotification object:self.view.window]; 

然后你可以改变尺寸：

- (void)keyboardWillShow:(NSNotification *)notif
{
[thetextView setFrame:CGRectMake(20, 49, 280, 187)]; //Or where ever you want the view to go


}

- (void)keyboardWillHide:(NSNotification *)notif
{
[thetextView setFrame:CGRectMake(20, 49, 280, 324)]; //return it to its original position

}

Answer 8

简而言之，注册键盘通知并在收到通知时进行调整大小的工作。

Answer 9

作为后续，当键盘通知发生时更新框架的技术不适用于 iOS 7。有关替代解决方案，请参阅以下内容：

How to re-size UITextView when keyboard shown with iOS 7

Answer 10

我在这里尝试了最佳答案，但我发现其中有问题。如果您在同一页面上有另一个文本字段，请单击该文本字段，显示键盘。您会注意到文本视图缩小了。但是，如果您现在单击文本视图，您会注意到文本视图大小再次缩小，而它不应该缩小。

我对这个问题的解决方案是在视图控制器中维护一个表示键盘状态（显示/隐藏）的属性。如果键盘当前可见，则不应缩小文本视图。如果您为不同的文本输入使用不同尺寸的键盘，您还应该保持旧的键盘尺寸。

请注意，此解决方案也没有考虑不同的方向，这可能会影响您计算文本视图大小的方式。

@implementation MyViewController {
    BOOL keyboardShown;
    NSInteger keyboardHeight;
}

- (void)moveTextViewForKeyboard:(NSNotification*)aNotification up: (BOOL) up{
    NSDictionary* userInfo = [aNotification userInfo];
    NSTimeInterval animationDuration;
    UIViewAnimationCurve animationCurve;
    CGRect keyboardEndFrame;

    [[userInfo objectForKey:UIKeyboardAnimationCurveUserInfoKey] getValue:&animationCurve];
    [[userInfo objectForKey:UIKeyboardAnimationDurationUserInfoKey] getValue:&animationDuration];
    [[userInfo objectForKey:UIKeyboardFrameEndUserInfoKey] getValue:&keyboardEndFrame];

    [UIView beginAnimations:nil context:nil];
    [UIView setAnimationDuration:animationDuration];
    [UIView setAnimationCurve:animationCurve];

    CGRect newFrame = self.textView.frame;
    CGRect keyboardFrame = [self.view convertRect:keyboardEndFrame toView:nil];

    NSInteger oldHeight = self->keyboardShown ? self->keyboardHeight : 0;
    NSInteger newHeight = up ? keyboardFrame.size.height : 0;
    NSInteger change = oldHeight - newHeight;

    self->keyboardShown = up;
    self->keyboardHeight = keyboardFrame.size.height;

    newFrame.size.height += change;
    self.textView.frame = newFrame;

    [UIView commitAnimations];
}