鍵盤出現時調整UITextView的大小

Question

我想在鍵盤出現時調整文本視圖的大小。 我的代碼如下。 我有自動布局，因此使用了來自superview的textView-> bottom space的約束，並通過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;
  }];
}

上面的代碼非常完美。 我不明白為什么我需要為iPhone6添加+78或為iPhone5添加183。 這兩個值我帶來了反復試驗。 如果我不添加這些，textView擴展到鍵盤下方。 請幫我解開這個謎。

Answer 1

在viewWillAppear方法中，添加以下內容：

- (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];    
}

然后實現通知中心的兩種方法，如下所示：

- (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);
}

而另一個像：

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

    yourTextView.contentInset = UIEdgeInsetsZero;
}

它適用於所有設備;）

Answer 2

Swift /修改版

使用上面的內容，我做了一些調整，以便在鍵盤顯示和隱藏時使用NSLayoutConstraint更改高度constant屬性。 如果您旋轉設備，這也適用。

1.設置TextView約束

然后控制從您的高度約束拖出一個出口到該類。

2.添加以下內容

    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

基於以上答案的Swift 5解決方案

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

當鍵盤pop覆蓋UITextView導致用戶無法看到已編輯的文本時，可以使用此處的解決方案。

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
    }
}