如何在键盘出现时在iOS上调整UITextView的大小？

Question

在UITabBarController （在iPhone上）的选项卡中插入了UITextView 。

1. 用很多行填充UITextView 。
2. 显示键盘以编辑文本。

发生了什么？ 键盘用光标隐藏了一半的UITextView 。 无法编辑文本作为结果。

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

Answer 1

以下代码达到了最佳结果。 另外不要忘了背景色设置为UIView并将UITextView 前等顶级屏幕控制（如UITabBar）。

最后编辑文本仍然不完美。 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]; 
}

PS没有stackoverflow就很难为iOS编码......

Answer 2

使用自动布局，您可以更轻松地（只要您了解自动布局）处理：

您只需为所有视图的内容创建父框架，而不是尝试识别和调整受影响的视图的大小。 然后，如果出现kbd，则调整框架大小，如果已正确设置约束，视图将很好地重新排列其所有子视图。 无需为此提供大量难以阅读的代码。

事实上，在类似的问题中，我找到了关于这种技术的优秀教程的链接。

Answer 3

我遇到了几个问题，试图让我的文本视图能够正确地滚动和动画，适用于iOS 7和iOS 8，以及新的QuickType功能。 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，并且无法使两者都正常工作。

然后我意识到我可以通过专注于框架简化事情，这对我来说有更多简单的代码。 综上所述：

• 注册UIKeyboardDidChangeFrameNotification （这将在QuickType显示/隐藏时通知）。
• 弄清楚你需要多少垂直空间来改变文本视图的框架。
• 动画帧大小更改。

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];
    }];
}

关于动画的快速说明。 我使用了Autolayout，因此我选择为文本视图的NSAutoLayoutConstraint设置动画，而不是直接设置框架。 为此，我在动画块之前和之内调用[self.view layoutIfNeeded] 。 这是动画约束的正确方法。 我在这里找到了这个提示。

Answer 4

值得注意的是，只有当设备处于纵向模式（而不是颠倒）时，upvoted答案才有效，在其他模式下，边界出错。 我相信你可以通过使用边界来修复它，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

- (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 
}

并且在dealloc中也注销了Notification

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

Answer 6

多年过去了，这个问题仍然存在。 Apple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 文档和错误修复的新解决方案。 它支持iOS 8，iOS 9，inputAccessoryView，可以用于新版本的iOS和新设备。

/* 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 7

首先将一些键盘方法添加到NSNotificationCenter defaultCenter

[[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]; 

然后你可以改变大小：

- (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

作为后续操作，在键盘通知发生时更新帧的技术对iOS 7不起作用。对于替代解决方案，请参阅以下内容：

当iOS 7显示键盘时，如何重新调整UITextView的大小

Answer 9

我在这里尝试了最好的答案但是我发现了一个问题。 如果您在同一页面上有另一个文本字段，则单击文本字段，显示键盘。 您会注意到文本视图缩小了。 但是，如果现在单击文本视图，您会注意到文本视图大小再次缩小，而不应该。

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的属性（显示/隐藏）。 如果键盘当前可见，则不应缩小文本视图。 如果您使用不同大小的键盘进行不同的文本输入，您还应该保持旧的键盘大小。

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];
}

Answer 10

简而言之，注册键盘通知并在收到通知后进行重新调整大小的工作。