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

有这么多的解决方案,但我花了几个小时才开始工作。因此,我将此代码放在这里(只需粘贴到项目中,无需进行任何修改):

@interface RegistrationViewController : UIViewController <UITextFieldDelegate>{
    UITextField* activeField;
    UIScrollView *scrollView;
}
@end

- (void)viewDidLoad
{
    [super viewDidLoad];

    scrollView = [[UIScrollView alloc] initWithFrame:self.view.frame];

    //scrool view must be under main view - swap it
    UIView* natView = self.view;
    [self setView:scrollView];
    [self.view addSubview:natView];

    CGSize scrollViewContentSize = self.view.frame.size;
    [scrollView setContentSize:scrollViewContentSize];

    [self registerForKeyboardNotifications];
}

- (void)viewDidUnload {
    activeField = nil;
    scrollView = nil;
    [self unregisterForKeyboardNotifications];
    [super viewDidUnload];
}

- (void)registerForKeyboardNotifications
{
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(keyboardWillShown:)
                                                 name:UIKeyboardWillShowNotification object:nil];

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

}

-(void)unregisterForKeyboardNotifications
{
    [[NSNotificationCenter defaultCenter] removeObserver:self
                                                    name:UIKeyboardWillShowNotification
                                                  object:nil];
    // unregister for keyboard notifications while not visible.
    [[NSNotificationCenter defaultCenter] removeObserver:self
                                                    name:UIKeyboardWillHideNotification
                                                  object:nil];
}

- (void)keyboardWillShown:(NSNotification*)aNotification
{
    NSDictionary* info = [aNotification userInfo];
    CGSize kbSize = [[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size;

    CGRect frame = self.view.frame;
    frame.size.height -= kbSize.height;
    CGPoint fOrigin = activeField.frame.origin;
    fOrigin.y -= scrollView.contentOffset.y;
    fOrigin.y += activeField.frame.size.height;
    if (!CGRectContainsPoint(frame, fOrigin) ) {
        CGPoint scrollPoint = CGPointMake(0.0, activeField.frame.origin.y + activeField.frame.size.height - frame.size.height);
        [scrollView setContentOffset:scrollPoint animated:YES];
    }
}

- (void)keyboardWillBeHidden:(NSNotification*)aNotification
{
     [scrollView setContentOffset:CGPointZero animated:YES];
}

- (void)textFieldDidBeginEditing:(UITextField *)textField
{
    activeField = textField;
}

- (void)textFieldDidEndEditing:(UITextField *)textField
{
    activeField = nil;
}

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

P.S:我希望这段代码能帮助某人快速达到预期效果。(Xcode 4.5)

其他回答

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()

一个适用于许多UITextFields的小补丁:

#pragma mark UIKeyboard handling

#define kMin 150

-(void)textFieldDidBeginEditing:(UITextField *)sender
{
    if (currTextField) {
        [currTextField release];
    }
    currTextField = [sender retain];
    // Move the main view, so that the keyboard does not hide it.
    if (self.view.frame.origin.y + currTextField.frame.origin. y >= kMin) {
        [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 = kMin - currTextField.frame.origin.y ;
    }
    else
    {
        // Revert back to the normal state.
        rect.origin.y = 0;
    }
    self.view.frame = rect;

    [UIView commitAnimations];
}


- (void)keyboardWillShow:(NSNotification *)notif
{
    // Keyboard will be shown now. Depending on which textfield is active, move up or move down the view appropriately

    if ([currTextField isFirstResponder] && currTextField.frame.origin.y + self.view.frame.origin.y >= kMin)
    {
        [self setViewMovedUp:YES];
    }
    else if (![currTextField isFirstResponder] && currTextField.frame.origin.y + self.view.frame.origin.y < kMin)
    {
        [self setViewMovedUp:NO];
    }
}


- (void)keyboardWillHide:(NSNotification *)notif
{
    // Keyboard will be shown now. Depending on which textfield is active, move up or move down the view appropriately
    if (self.view.frame.origin.y < 0 ) {
        [self setViewMovedUp:NO];
    }
}


- (void)viewWillAppear:(BOOL)animated
{
    // Register for keyboard notifications
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillShow:)
                                                 name:UIKeyboardWillShowNotification object:self.view.window];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillHide:)
                                                 name:UIKeyboardWillHideNotification object:self.view.window];
}

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

从Dune Buggy的回答中得到了参考。根据TextField的位置向上滚动视图。因为现有的答案是滚动屏幕的整个视图,所以我需要根据文本字段的框架滚动视图。

键盘WillShow

@objc func keyboardWillShow(notification: NSNotification) {
    
    guard let keyboardSize = (notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue else {
        
        // if keyboard size is not available for some reason, don't do anything
        return
    }
    let keyboardFrame = keyboardSize
    
    let maxheightScreen = self.view.frame
    
    
    if (self.txtEmail.frame.origin.y + ((self.txtEmail.superview)!.frame.maxY) + keyboardSize.height) >= maxheightScreen.size.height{
        if self.view.frame.origin.y == 0 {
            self.view.frame.origin.y -= (keyboardFrame.height - (self.txtEmail.frame.maxY + 120)) // Here i added 120 additional height for my additional view space
        }
    }
}

键盘将隐藏

@objc func keyboardWillHide(notification: NSNotification) {
    
    guard let keyboardSize = (notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue else {
        // if keyboard size is not available for some reason, don't do anything
        return
    }
    
    let keyboardFrame = keyboardSize
    
    if self.view.frame.origin.y != 0 {
        self.view.frame.origin.y += (keyboardFrame.height - (self.txtEmail.frame.maxY + 120))
    }
}

这是独立于设备的偏移计算。获取键盘和文本字段之间的重叠高度:

func keyboardShown(notification: NSNotification) {
    let info  = notification.userInfo!
    let value: AnyObject = info[UIKeyboardFrameEndUserInfoKey]!

    let rawFrame = value.CGRectValue
    let keyboardFrame = view.convertRect(rawFrame, fromView: nil)

    let screenHeight = UIScreen.mainScreen().bounds.size.height;
    let Ylimit = screenHeight - keyboardFrame.size.height
    let textboxOriginInSuperview:CGPoint = self.view.convertPoint(CGPointZero, fromCoordinateSpace: lastTextField!)

    self.keyboardHeight = (textboxOriginInSuperview.y+self.lastTextField!.frame.size.height) - Ylimit

    if(self.keyboardHeight>0){
        self.animateViewMoving(true, moveValue: keyboardHeight!)
    }else{
        keyboardHeight=0
    }
}

keyBoardHeight是偏移量。

刚找到这个类:

https://github.com/OliverLetterer/SLScrollViewKeyboardSupport

到目前为止,它在iPhone上运行得很好,包括动画和正确的偏移。

要使用它,只需添加到viewDidLoad:

self.support = [[SLScrollViewKeyboardSupport alloc] initWithScrollView:self.scrollView];