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

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

其他回答

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)
}

我认为没有“正确”的方法来做这件事。您必须为您的用例选择最合适的解决方案。 在我的iPad App中,我有一个UIViewController,它以UIModalPresentationFormSheet的形式呈现,由一个UITableView组成。这个表格每个单元格包含两个UITextFields。 只是调用scrollToRowAtIndexPath:atScrollPosition:animated:在textFieldDidBeginEditing:方法不为我工作。因此,我创建了一个tableFooterView:

- (void)viewDidLoad
{
    [super viewDidLoad];

    m_footerView = [[UIView alloc] initWithFrame:CGRectMake(0.0f, 0.0f, m_tableView.frame.size.width, 300.0f)];
    [m_footerView setBackgroundColor:[UIColor clearColor]];
    [m_tableView setTableFooterView:m_footerView];
    [m_footerView release];
}

这个想法是键盘隐藏tableFooterView而不是UITextFields。tableFooterView必须足够高。之后,你可以在textFieldDidBeginEditing:方法中使用scrollToRowAtIndexPath:atScrollPosition:animated:。

我认为也可以通过添加键盘通知的观察者来动态地显示和隐藏tableFooterView,但我还没有尝试过:

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

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

- (void)keyboardWillShow:(NSNotification *)notification 
{
     [m_tableView setTableFooterView:m_footerView];
}

- (void)keyboardWillHide:(NSNotification *)notification 
{
     [m_tableView setTableFooterView:nil];
}

- (void)viewWillDisappear:(BOOL)animated
{
    [super viewWillDisappear:animated];

    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillShowNotification object:nil];
    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillHideNotification object:nil];
}

不需要任何计算,使用下面的代码,它将工作: 这段代码我用在我的自定义UITableviewcell,它是工作的:

override func viewDidLoad() {
super.viewDidLoad()

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

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


func keyboardWillShow(_ notification:Notification) {

if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
    tableView.contentInset = UIEdgeInsetsMake(0, 0, keyboardSize.height, 0)
}}


func keyboardWillHide(_ notification:Notification) {

if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
    tableView.contentInset = UIEdgeInsetsMake(0, 0, 0, 0)
}}

执行滚动的函数可以简单得多:

- (void) textFieldDidBeginEditing:(UITextField *)textField {
    UITableViewCell *cell;

    if (floor(NSFoundationVersionNumber) <= NSFoundationVersionNumber_iOS_6_1) {
    // Load resources for iOS 6.1 or earlier
        cell = (UITableViewCell *) textField.superview.superview;

    } else {
        // Load resources for iOS 7 or later
        cell = (UITableViewCell *) textField.superview.superview.superview; 
       // TextField -> UITableVieCellContentView -> (in iOS 7!)ScrollView -> Cell!
    }
    [tView scrollToRowAtIndexPath:[tView indexPathForCell:cell] atScrollPosition:UITableViewScrollPositionTop animated:YES];
}

就是这样。根本不需要计算。

如果你的UITableView是由UITableViewController的子类管理的,而不是UITableView,并且文本字段委托是UITableViewController,它应该自动管理所有的滚动——所有这些其他注释在实践中是很难实现的。

有关一个好例子,请参阅apple示例代码项目:TaggedLocations。

你可以看到它自动滚动,但似乎没有任何代码做到这一点。该项目还具有自定义表视图单元格,因此,如果使用它作为指南构建应用程序,应该会得到预期的结果。