经过大量的试验和错误,我放弃了,并提出了这个问题。我见过很多人有类似的问题,但不能得到所有的答案工作正确。

我有一个由自定义单元格组成的UITableView。单元格由相邻的5个文本字段组成(有点像网格)。

当我试图滚动和编辑UITableView底部的单元格时,我不能设法让我的单元格正确地定位在键盘上方。

我看到过很多关于改变视图大小的回答……但到目前为止,没有一种效果很好。

谁能用一个具体的代码示例来阐明这样做的“正确”方式?


当前回答

我想我已经想出了与苹果应用程序行为相匹配的解决方案。

首先,在viewWillAppear:订阅键盘通知,这样你就知道什么时候键盘会显示和隐藏,系统会告诉你键盘的大小,但不要忘记在viewWillDisappear:中取消注册。

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

实现类似于下面的方法,以便在键盘显示时调整tableView的大小以匹配可见区域。这里我单独跟踪键盘的状态,所以我可以自己选择何时将tableView设置为全高度,因为你在每个字段更改时都会收到这些通知。不要忘记实现keyboardWillHide:并选择适当的地方来修复你的tableView大小。

-(void) keyboardWillShow:(NSNotification *)note
{
    CGRect keyboardBounds;
    [[note.userInfo valueForKey:UIKeyboardBoundsUserInfoKey] getValue: &keyboardBounds];
    keyboardHeight = keyboardBounds.size.height;
    if (keyboardIsShowing == NO)
    {
        keyboardIsShowing = YES;
        CGRect frame = self.view.frame;
        frame.size.height -= keyboardHeight;

        [UIView beginAnimations:nil context:NULL];
        [UIView setAnimationBeginsFromCurrentState:YES];
        [UIView setAnimationDuration:0.3f];
        self.view.frame = frame;
        [UIView commitAnimations];
    }
}

现在这是滚动位,我们先计算出一些大小,然后我们看到我们在可见区域中的位置,并设置我们想要滚动的矩形,根据它在视图中的位置,将它设置为文本字段中间上方或下方的半视图。在本例中,我们有一个UITextFields数组和一个用于跟踪它们的enum,因此用rowHeight乘以行号就得到了这个外部视图中帧的实际偏移量。

- (void) textFieldDidBeginEditing:(UITextField *)textField
{
    CGRect frame = textField.frame;
    CGFloat rowHeight = self.tableView.rowHeight;
    if (textField == textFields[CELL_FIELD_ONE])
    {
        frame.origin.y += rowHeight * CELL_FIELD_ONE;
    }
    else if (textField == textFields[CELL_FIELD_TWO])
    {
        frame.origin.y += rowHeight * CELL_FIELD_TWO;
    }
    else if (textField == textFields[CELL_FIELD_THREE])
    {
        frame.origin.y += rowHeight * CELL_FIELD_THREE;
    }
    else if (textField == textFields[CELL_FIELD_FOUR])
    {
        frame.origin.y += rowHeight * CELL_FIELD_FOUR;
    }
    CGFloat viewHeight = self.tableView.frame.size.height;
    CGFloat halfHeight = viewHeight / 2;
    CGFloat midpoint = frame.origin.y + (textField.frame.size.height / 2);
    if (midpoint < halfHeight)
    {
        frame.origin.y = 0;
        frame.size.height = midpoint;
    }
    else
    {
        frame.origin.y = midpoint;
        frame.size.height = midpoint;
    }
    [self.tableView scrollRectToVisible:frame animated:YES];
}

这似乎工作得很好。

其他回答

另一个简单的方法(只适用于一个部分)

//cellForRowAtIndexPath
UItextField *tf;
[cell addSubview:tf];
tf.tag = indexPath.row;
tf.delegate = self;

//textFieldDidBeginEditing:(UITextField *)text
[[self.tableView scrollToRowsAtIndexPath:[NSIndexPath indexPathForRow:text.tag in section:SECTIONINTEGER] animated:YES];

Swift 3-4动画和键盘帧改变的解决方案:

首先,创建Bool类型:

// MARK: - Private Properties
private var isKeyboardShowing = false

其次,在系统键盘通知中添加观察者:

// MARK: - Overriding ViewController Life Cycle Methods
override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)

    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow), name: .UIKeyboardWillShow, object: nil)

    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide), name: .UIKeyboardWillHide, object: nil)

    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillChangeFrame), name: .UIKeyboardWillChangeFrame, object: nil)
}

第三,准备动画功能:

func adjustTableViewInsets(keyboardHeight: CGFloat, duration: NSNumber, curve: NSNumber){
    var extraHeight: CGFloat = 0
    if keyboardHeight > 0 {
        extraHeight = 20
        isKeyboardShowing = true
    } else {
        isKeyboardShowing = false
    }

    let contentInset = UIEdgeInsets(top: 0, left: 0, bottom: keyboardHeight + extraHeight, right: 0)
    func animateFunc() {
        //refresh constraints
        //self.view.layoutSubviews()
        tableView.contentInset = contentInset
    }

    UIView.animate(withDuration: TimeInterval(duration), delay: 0, options: [UIViewAnimationOptions(rawValue: UInt(curve))], animations: animateFunc, completion: nil)
}

然后添加target/action方法(由观察者调用):

// MARK: - Target/Selector Actions
func keyboardWillShow(notification: NSNotification) {
    if !isKeyboardShowing {
        if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
            let keyboardHeight = keyboardSize.height

            let duration = notification.userInfo?[UIKeyboardAnimationDurationUserInfoKey] as! NSNumber
            let curve = notification.userInfo?[UIKeyboardAnimationCurveUserInfoKey] as! NSNumber

            adjustTableViewInsets(keyboardHeight: keyboardHeight, duration: duration, curve: curve)
        }
    }
}

func keyboardWillHide(notification: NSNotification) {
    let duration = notification.userInfo?[UIKeyboardAnimationDurationUserInfoKey] as! NSNumber
    let curve = notification.userInfo?[UIKeyboardAnimationCurveUserInfoKey] as! NSNumber
    adjustTableViewInsets(keyboardHeight: 0, duration: duration, curve: curve)
}

func keyboardWillChangeFrame(notification: NSNotification) {
    if isKeyboardShowing {
        let duration = notification.userInfo?[UIKeyboardAnimationDurationUserInfoKey] as! NSNumber
        let curve = notification.userInfo?[UIKeyboardAnimationCurveUserInfoKey] as! NSNumber

        if let newKeyboardSize = (notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {
            let keyboardHeight = newKeyboardSize.height
            adjustTableViewInsets(keyboardHeight: keyboardHeight, duration: duration, curve: curve)
        }
    }
}

最后,不要忘记在deinit或viewWillDisappear中删除观察者:

deinit {
    NotificationCenter.default.removeObserver(self)
}

一个更加流线型的解决方案。它滑入UITextField委托方法,所以它不需要搞砸/ UIKeyboard通知。

实现注意事项:

kSettingsRowHeight——UITableViewCell的高度。

offsetTarget和offsetThreshold基于kSettingsRowHeight。如果使用不同的行高,则将这些值设置为point的y属性。[alt:以不同的方式计算行偏移量。]

- (BOOL)textFieldShouldBeginEditing:(UITextField *)textField {
CGFloat offsetTarget    = 113.0f; // 3rd row
CGFloat offsetThreshold = 248.0f; // 6th row (i.e. 2nd-to-last row)

CGPoint point = [self.tableView convertPoint:CGPointZero fromView:textField];

[UIView beginAnimations:nil context:nil];
[UIView setAnimationDuration:0.2];
[UIView setAnimationCurve:UIViewAnimationCurveEaseOut];

CGRect frame = self.tableView.frame;
if (point.y > offsetThreshold) {
    self.tableView.frame = CGRectMake(0.0f,
                      offsetTarget - point.y + kSettingsRowHeight,
                      frame.size.width,
                      frame.size.height);
} else if (point.y > offsetTarget) {
    self.tableView.frame = CGRectMake(0.0f,
                      offsetTarget - point.y,
                      frame.size.width,
                      frame.size.height);
} else {
    self.tableView.frame = CGRectMake(0.0f,
                      0.0f,
                      frame.size.width,
                      frame.size.height);
}

[UIView commitAnimations];

return YES;

}

- (BOOL)textFieldShouldReturn:(UITextField *)textField {
[textField resignFirstResponder];

[UIView beginAnimations:nil context:nil];
[UIView setAnimationBeginsFromCurrentState:YES];
[UIView setAnimationDuration:0.2];
[UIView setAnimationCurve:UIViewAnimationCurveEaseOut];

CGRect frame = self.tableView.frame;
self.tableView.frame = CGRectMake(0.0f,
                  0.0f,
                  frame.size.width,
                  frame.size.height);

[UIView commitAnimations];

return YES;

}

我将把我的解决方案(或者QuickDialog的)扔进帽子里。基本上是等待动画到滚动。获得键盘动画JIT而不是神奇的数字会很好。

-(void)textFieldDidBeginEditing:(UITextField *)textField
{
    if (textField == self.emailTextField) {
        NSIndexPath *indexPath = [NSIndexPath indexPathForRow:0 inSection:0];
        dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, 50 * USEC_PER_SEC);
        dispatch_after(popTime, dispatch_get_main_queue(), ^(void){
            [self.tableView scrollToRowAtIndexPath:indexPath atScrollPosition:UITableViewScrollPositionTop animated:YES];
        });
    }
}

如果你使用UITableViewController而不是UIViewController,它会自动这样做。