如何在键盘出现时在iOS上调整UITextView的大小？

Question

已UITextView插入UITabBarController(在iPhone上)的标签中.

1. 填写UITextView很多行.
2. 显示键盘以编辑文本.

发生了什么？键盘UITextView用光标隐藏了一半.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.另外不要忘记设置背景颜色UIView和地点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,则调整框架的大小,如果已正确设置约束,则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

多年过去了，这个问题仍然是现实的。苹果绝对应该自己处理所有这些事情。但事实并非如此。这是基于苹果官方文档加上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;
}