使用iOS SDK:

我有一个带UITextFields的UIView,可以启动键盘。我需要它能够:

启动键盘后,允许滚动UIScrollView的内容以查看其他文本字段自动“跳转”(通过向上滚动)或缩短

我知道我需要一个UIScrollView。我已经尝试将UIView的类更改为UIScrollView,但仍然无法上下滚动文本框。

我需要UIView和UIScrollView吗?一个在另一个里面吗?

要自动滚动到活动文本字段,需要执行哪些操作?

理想情况下,尽可能多的组件设置将在Interface Builder中完成。我只想编写需要的代码。

注意:我使用的UIView(或UIScrollView)是由一个选项卡(UITabBar)启动的,它需要正常工作。


我正在添加滚动条,只为键盘出现时使用。尽管不需要它,但我觉得它提供了一个更好的界面,例如,用户可以滚动和更改文本框。

当键盘上下移动时,我可以改变UIScrollView的框架大小。我只是在使用:

-(void)textFieldDidBeginEditing:(UITextField *)textField {
    //Keyboard becomes visible
    scrollView.frame = CGRectMake(scrollView.frame.origin.x,
                                  scrollView.frame.origin.y,
    scrollView.frame.size.width,
    scrollView.frame.size.height - 215 + 50);   // Resize
}

-(void)textFieldDidEndEditing:(UITextField *)textField {
    // Keyboard will hide
    scrollView.frame = CGRectMake(scrollView.frame.origin.x,
                                  scrollView.frame.origin.y,
                                  scrollView.frame.size.width,
                                  scrollView.frame.size.height + 215 - 50); // Resize
}

然而,这不会自动“向上移动”或将可见区域中的下部文本字段居中,这是我真正想要的。


当前回答

雨燕5

在viewDidLoad或viewDidAppear中添加addKeyboardObserver方法。

fileprivate func addKeyboardObservers(){
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow), name: UIResponder.keyboardWillShowNotification, object: nil)

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

fileprivate func removeKeyboardObservers(){
    NotificationCenter.default.removeObserver(self, name: UIResponder.keyboardWillHideNotification, object: nil)
    NotificationCenter.default.removeObserver(self, name: UIResponder.keyboardWillShowNotification, object: nil)
}


@objc fileprivate func keyboardWillHide(_ notification: Notification){
    if (window == nil) {return}
    guard let duration = (notification.userInfo?[UIResponder.keyboardAnimationDurationUserInfoKey] as? Double) else {return}

   scrollView.contentInset.bottom = .zero
}


@objc fileprivate func keyboardWillShow(_ notification: Notification){
    if (window == nil) {return}
    if UIApplication.shared.applicationState != .active { return }

    // keyboard height
    guard let height = (notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? CGRect)?.height else {return}
    // keyboard present animation duration
    guard let duration = (notification.userInfo?[UIResponder.keyboardAnimationDurationUserInfoKey] as? Double) else {return}

   scrollView.contentInset.bottom = height
}

不要忘记删除或消失观察者

    self.removeKeyboardObservers()

其他回答

使用这个第三方,你甚至不需要写一行

https://github.com/hackiftekhar/IQKeyboardManager

下载项目并在项目中拖放IQKeyboardManager。如果您发现任何问题,请阅读README文档。

伙计们管理键盘真的很头疼。

注意:此答案假设您的textField位于scrollView中。

我更喜欢使用scrollContentInset和scrollContentOffset来处理这个问题,而不是干扰视图的框架。

首先让我们听听键盘通知

//call this from viewWillAppear
-(void)addKeyboardNotifications
{
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(keyboardWillShow:)
                                                 name:UIKeyboardWillShowNotification
                                               object:nil];

    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(keyboardWillHide:)
                                                 name:UIKeyboardWillHideNotification
                                               object:nil];
}
//call this from viewWillDisappear
-(void)removeKeyboardNotifications{
    [[NSNotificationCenter default
    Center] removeObserver:self name:UIKeyboardWillShowNotification object:nil];
    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillHideNotification object:nil];
}

下一步是保留表示当前第一响应者的属性(当前具有键盘的UITextfield/UUITextVIew)。

我们使用委托方法来设置此属性。如果您正在使用另一个组件,则需要类似的组件。

请注意,对于textfield,我们在didBegginEditing中设置它,而对于textView,我们在shouldBeginEditing中将其设置。这是因为出于某种原因,在UIKeyboardWillShowNotification之后调用textViewDidBegginEditing。

-(BOOL)textViewShouldBeginEditing:(UITextView * )textView{
    self.currentFirstResponder = textView;
    return YES;
}

-(void)textFieldDidBeginEditing:(UITextField *)textField{
    self.currentFirstResponder = textField;
}

最后,这里是魔术

- (void)keyboardWillShow:(NSNotification*)aNotification{
    NSDictionary* info = [aNotification userInfo];
    CGRect kbFrame = [[info objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue];


    /*if currentFirstResponder is overlayed by the keyboard, move it so it bottom ends where the keyboard begins*/
    if(self.currentFirstResponder){

        //keyboard origin in currentFirstResponderFrame
        CGPoint keyboardOrigin = [self.currentFirstResponder convertPoint:kbFrame.origin fromView:nil];

        float spaceBetweenFirstResponderAndKeyboard = abs(self.currentFirstResponder.frame.size.height-keyboardOrigin.y);

        //only scroll the scrollview if keyboard overlays the first responder
        if(spaceBetweenFirstResponderAndKeyboard>0){
            //if i call setContentOffset:animate:YES it behaves differently, not sure why
            [UIView animateWithDuration:0.25 animations:^{
                [self.scrollView setContentOffset:CGPointMake(0,self.scrollView.contentOffset.y+spaceBetweenFirstResponderAndKeyboard)];
            }];
        }
    }

    //set bottom inset to the keyboard height so you can still scroll the whole content

    UIEdgeInsets contentInsets = UIEdgeInsetsMake(0.0, 0.0, kbFrame.size.height, 0.0);
    _scrollView.contentInset = contentInsets;
    _scrollView.scrollIndicatorInsets = contentInsets;

}

- (void)keyboardWillHide:(NSNotification*)aNotification{
    UIEdgeInsets contentInsets = UIEdgeInsetsZero;
    _scrollView.contentInset = contentInsets;
    _scrollView.scrollIndicatorInsets = contentInsets;
}

如果您现在的内容不适合iPhone屏幕,您只需要一个ScrollView。(如果您添加ScrollView作为组件的超级视图,只是为了在键盘启动时使TextField向上滚动,那么就不需要了。)防止TextFields被键盘覆盖的标准方法是在显示键盘时向上/向下移动视图。

下面是一些示例代码:

#define kOFFSET_FOR_KEYBOARD 80.0

-(void)keyboardWillShow {
    // Animate the current view out of the way
    if (self.view.frame.origin.y >= 0)
    {
        [self setViewMovedUp:YES];
    }
    else if (self.view.frame.origin.y < 0)
    {
        [self setViewMovedUp:NO];
    }
}

-(void)keyboardWillHide {
    if (self.view.frame.origin.y >= 0)
    {
        [self setViewMovedUp:YES];
    }
    else if (self.view.frame.origin.y < 0)
    {
        [self setViewMovedUp:NO];
    }
}

-(void)textFieldDidBeginEditing:(UITextField *)sender
{
    if ([sender isEqual:mailTf])
    {
        //move the main view, so that the keyboard does not hide it.
        if  (self.view.frame.origin.y >= 0)
        {
            [self setViewMovedUp:YES];
        }
    }
}

//method to move the view up/down whenever the keyboard is shown/dismissed
-(void)setViewMovedUp:(BOOL)movedUp
{
    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationDuration:0.3]; // if you want to slide up the view

    CGRect rect = self.view.frame;
    if (movedUp)
    {
        // 1. move the view's origin up so that the text field that will be hidden come above the keyboard 
        // 2. increase the size of the view so that the area behind the keyboard is covered up.
        rect.origin.y -= kOFFSET_FOR_KEYBOARD;
        rect.size.height += kOFFSET_FOR_KEYBOARD;
    }
    else
    {
        // revert back to the normal state.
        rect.origin.y += kOFFSET_FOR_KEYBOARD;
        rect.size.height -= kOFFSET_FOR_KEYBOARD;
    }
    self.view.frame = rect;

    [UIView commitAnimations];
}


- (void)viewWillAppear:(BOOL)animated
{
    [super viewWillAppear:animated];
    // register for keyboard notifications
    [[NSNotificationCenter defaultCenter] addObserver:self
                                         selector:@selector(keyboardWillShow)
                                             name:UIKeyboardWillShowNotification
                                           object:nil];

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

- (void)viewWillDisappear:(BOOL)animated
{
    [super viewWillDisappear:animated];
    // unregister for keyboard notifications while not visible.
    [[NSNotificationCenter defaultCenter] removeObserver:self
                                             name:UIKeyboardWillShowNotification
                                           object:nil];

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

这是我使用自动布局的版本:

其想法是将包含文本字段/文本视图的视图嵌入UIScrollView中,从底部到其超级视图设置一个约束,创建一个出口,并使用通知根据键盘高度更新其常量。这是基于此处的Apple示例,以及此处使用AutoLayout的UIScrollView上的Apple技术说明。

1) 将视图V嵌入UIScrollView S:如果已经设置了常量和子视图,则可以在ViewController的视图中复制/粘贴视图和子视图;然后使用编辑器->嵌入菜单嵌入视图,最后删除复制的视图。)

2) 设置以下约束:

S到顶部布局指南:0S至底部布局指南:0通向超级视图的S:0S尾随到超级视图:0V顶部空间到超级视图:0V底部空间到超级视图:0超级视图的V尾随空格:0超视图的V前导空格:0V等于S的宽度最新底部V子视图到超级视图:20

3) 从视图控制器的最新约束创建出口

4) 使用以下代码:

@property (weak, nonatomic) IBOutlet NSLayoutConstraint *bottomSpaceToContentView;

// ...

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.

    // ...

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

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

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

#pragma mark - Handle keyboard

// Called when the UIKeyboardDidShowNotification is sent.
- (void)keyboardWasShown:(NSNotification*)aNotification
{
    NSDictionary* info = [aNotification userInfo];
    CGSize kbSize = [[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size;

    self.bottomSpaceToContentView.constant = kBottomMargin + kbSize.height;
    [self.view layoutIfNeeded];
}

// Called when the UIKeyboardWillHideNotification is sent
- (void)keyboardWillBeHidden:(NSNotification*)aNotification
{
    self.bottomSpaceToContentView.constant = kBottomMargin;
    [self.view layoutIfNeeded];
}

哈哈,它起作用了!

https://github.com/michaeltyson/TPKeyboardAvoiding下载此文件并添加自定义类,因为它将在您的表视图中管理所有内容,您无需执行任何操作。它有很多选项,你也可以为其他人查看,这是你需要避免使用键盘的全部