出现键盘时调整 UITextView 的大小

Question

我想在出现键盘时调整文本视图的大小。我的代码如下。我启用了自动布局，因此使用来自 superview 的 textView->bottom space 的约束并通过 IBOutlet distanceFromBottom.

引用它

- (void)keyboardWillShow:(NSNotification *)notification
{
  [UIView animateWithDuration:0.3 animations:^{
    NSDictionary* d = [notification userInfo];
    CGRect r = [d[UIKeyboardFrameEndUserInfoKey] CGRectValue];
    r = [textView convertRect:r fromView:Nil];
    if(IS_IPHONE_6||IS_IPHONE_6P)
      distanceFromBottom.constant = r.origin.y+78;
    else if(IS_IPHONE_5)
      distanceFromBottom.constant = r.origin.y+183;
  }];
}

上面的代码运行完美。我不明白的是为什么我需要为 iPhone6 添加 +78 或为 iPhone5 添加 183。这两个值是我通过反复试验得出的。如果我不添加这些，textView 会延伸到键盘下方。请帮我解开这个谜。

Answer 1

在viewWillAppear方法中，添加以下内容：

- (void) viewWillAppear:(BOOL)paramAnimated{
    [super viewWillAppear:paramAnimated];

    [[NSNotificationCenter defaultCenter] 
        addObserver:self 
           selector:@selector(handleKeyboardDidShow:) 
               name:UIKeyboardDidShowNotification object:nil];

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

然后实现通知中心的两个方法，像这样：

- (void) handleKeyboardDidShow:(NSNotification *)paramNotification{

    NSValue *keyboardRectAsObject =
        [[paramNotification userInfo] 
            objectForKey:UIKeyboardFrameEndUserInfoKey];

    CGRect keyboardRect = CGRectZero;
    [keyboardRectAsObject getValue:&keyboardRect];

    yourTextView.contentInset =
        UIEdgeInsetsMake(0.0f,
                         0.0f,
                         keyboardRect.size.height,
                         0.0f);
}

另一个喜欢：

- (void) handleKeyboardWillHide:(NSNotification *)paramNotification{

    yourTextView.contentInset = UIEdgeInsetsZero;
}

它将适用于所有设备 ;)

Answer 2

Swift / 修改版本

利用上面的内容，我做了一些调整，以在键盘显示和隐藏时使用NSLayoutConstraint改变高度constant 属性。如果您旋转设备，这也有效。

1.设置 TextView 约束

然后控制从您的高度限制拖动出口到 class。

2。添加以下内容

    override func viewWillAppear(animated: Bool) {
        super.viewWillAppear(animated)

        NSNotificationCenter.defaultCenter().addObserver(self, selector:#selector(SkillDescriptionViewController.keyboardWillShowHandle(_:)), name: UIKeyboardDidShowNotification, object: nil)

        NSNotificationCenter.defaultCenter().addObserver(self, selector:#selector(SkillDescriptionViewController.keyboardWillHideHandle), name: UIKeyboardWillHideNotification, object: nil)

    }


    func keyboardWillShowHandle(note:NSNotification) {
        guard let keyboardRect = note.userInfo![UIKeyboardFrameEndUserInfoKey] as? NSValue else { return }
        let kbFrame = keyboardRect.CGRectValue()
        tvHeight.constant = -kbFrame.height
        view.layoutIfNeeded()
    }

    func keyboardWillHideHandle() {
        tvHeight.constant = 0
        view.layoutIfNeeded()
    }

Answer 3

Swift 5 解决方案基于上述答案

通知 API 已更改 (20190707) 以及如何使用 #selector

当键盘弹出覆盖UITextView导致用户看不到被编辑的文本时，可以使用这里的解决方案。

import UIKit

class DCNodeLogEntryViewController: UIViewController {
    @IBOutlet weak var textViewNodeLogEntry: UITextView!

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)

        NotificationCenter.default.addObserver(
            self,
            selector: #selector(DCNodeLogEntryViewController.handleKeyboardDidShow(notification:)),
            name: UIResponder.keyboardDidShowNotification,
            object: nil
        )

        NotificationCenter.default.addObserver(
            self,
            selector: #selector(DCNodeLogEntryViewController.handleKeybolardWillHide),
            name: UIResponder.keyboardWillHideNotification,
            object: nil
        )
    }

    @objc func handleKeyboardDidShow(notification: NSNotification) {
        guard let keyboardRect = notification
            .userInfo![UIResponder.keyboardFrameEndUserInfoKey]
            as? NSValue else { return }

        let frameKeyboard = keyboardRect.cgRectValue

        textViewNodeLogEntry.contentInset = UIEdgeInsets(
            top: 0.0,
            left: 0.0,
            bottom: frameKeyboard.size.height,
            right: 0.0
        )

        view.layoutIfNeeded()
    }

    @objc func handleKeybolardWillHide() {
        textViewNodeLogEntry.contentInset = .zero
    }
}

出现键盘时调整 UITextView 的大小

Resize the UITextView when keyboard appears

objective-c

uitextview

ios