IOS/Xcode：如何在出现键盘时向上移动视图

IOS/Xcode: How to Move View Up when Keyboard appears

提问by user1904273

There are many answers on this on SO but most are from years ago and none seem quite satisfactory.

关于这个问题有很多答案，但大多数是几年前的，而且似乎都不太令人满意。

For a login screen with just three textfields and submit button, I want the view to move up when the keyboard appears just enough so that while the field is not hidden, it also does not move up out of view. The amount of movement needed is such that the submit button is a fixed distance above the keyboard. While it is possible by moving the fields high up on the page to leave room for the keyboard, the submit button is still hidden

对于只有三个文本字段和提交按钮的登录屏幕，我希望在键盘出现时视图向上移动，这样虽然该字段没有隐藏，但它也不会向上移出视图。所需的移动量使得提交按钮位于键盘上方的固定距离。虽然可以通过在页面上向上移动字段为键盘留出空间，但提交按钮仍然隐藏

I tried just adding the following:

我尝试添加以下内容：

-(void) viewWillAppear:(BOOL)Animated {
    [[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 {
    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillShowNotification object:nil];
    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillHideNotification object:nil];
}

This moves the view up a fixed amount but so much so that the fields are not visible for editing, i.e. they are too high up.

这会将视图向上移动一个固定的量，但如此之大，以至于字段对于编辑不可见，即它们太高了。

Another SO answer suggested:

另一个 SO 答案建议：

-(void)textFieldDidBeginEditing:(UITextField *)textField
{
    [self animateTextField:textField up:YES];
}

- (void)textFieldDidEndEditing:(UITextField *)textField
{
    [self animateTextField:textField up:NO];
}

-(void)animateTextField:(UITextField*)textField up:(BOOL)up
{
    const int movementDistance = -200; // tweak as needed
    const float movementDuration = 0.3f; // tweak as needed

    int movement = (up ? movementDistance : -movementDistance);

    [UIView beginAnimations: @"animateTextField" context: nil];
    [UIView setAnimationBeginsFromCurrentState: YES];
    [UIView setAnimationDuration: movementDuration];
    self.view.frame = CGRectOffset(self.view.frame, 0, movement);
    [UIView commitAnimations];
}

I can't figure out how to implement this. If you just leave it as is nothing happens. I guess you are supposed to rename textfield with the name of your textfield but in that case, would you do it for each of the textfields? I cannot get it to have any effect.

我无法弄清楚如何实现这一点。如果你只是保持原样，什么都不会发生。我想你应该用你的文本字段的名称重命名文本字段，但在这种情况下，你会为​​每个文本字段都这样做吗？我无法让它产生任何效果。

Another suggestion is to use a category such as TPKeyboardAvoiding however this requires a scrollview that I do not need in this case.

另一个建议是使用诸如 TPKeyboardAvoiding 之类的类别，但是这需要一个我在这种情况下不需要的滚动视图。

Is there no straightforward solution in 2015 for this issue?

2015 年有没有针对这个问题的直接解决方案？

Thanks for any suggestions/guidance.

感谢您的任何建议/指导。

回答by Fawad Masud

The following animation will move your view (viewForLogin in this case) 200 pixels above when the user starts typing. The view will animate back to original position when the textfield ends editing. Do not forget to set the delegates for the textfields.

当用户开始输入时，以下动画会将您的视图（在本例中为 viewForLogin）移动 200 像素以上。当文本字段结束编辑时，视图将动画回到原始位置。不要忘记为文本字段设置代表。

Swift 3

斯威夫特 3

func textFieldDidBeginEditing(_ textField: UITextField) {
    UIView.animate(withDuration: 0.3, animations: {
        self.view.frame = CGRect(x:self.view.frame.origin.x, y:self.view.frame.origin.y - 200, width:self.view.frame.size.width, height:self.view.frame.size.height);

    })
}

func textFieldDidEndEditing(_ textField: UITextField) {
    UIView.animate(withDuration: 0.3, animations: {
        self.viewSupport.frame = CGRect(x:self.viewSupport.frame.origin.x, y:self.viewSupport.frame.origin.y + 200, width:self.viewSupport.frame.size.width, height:self.viewSupport.frame.size.height);

    })
}

Objective-C

目标-C

-(void)textFieldDidBeginEditing:(UITextField *)textField
{
    [UIView beginAnimations:nil context:nil];
    [UIView setAnimationDuration:.3];
    [UIView setAnimationBeginsFromCurrentState:TRUE];
    self.view.frame = CGRectMake(self.view.frame.origin.x, self.view.frame.origin.y -200., self.view.frame.size.width, self.view.frame.size.height);

    [UIView commitAnimations];


}


-(void)textFieldDidEndEditing:(UITextField *)textField
{
    [UIView beginAnimations:nil context:nil];
    [UIView setAnimationDuration:.3];
    [UIView setAnimationBeginsFromCurrentState:TRUE];
    self.view.frame = CGRectMake(self.view.frame.origin.x, self.view.frame.origin.y +200., self.view.frame.size.width, self.view.frame.size.height);

    [UIView commitAnimations];

}

回答by Mohammad Sadiq

SWIFTlovers Here you go. I have used this code with UIView, though. You should be able to make those adjustments for scrollview.

SWIFT爱好者 给你。不过，我已将此代码与 UIView 一起使用。您应该能够对滚动视图进行这些调整。

    func addKeyboardNotifications() {
        NotificationCenter.default.addObserver(self,
                                               selector: #selector(keyboardWillShow(notification:)),
                                               name: NSNotification.Name.UIKeyboardWillShow, object: nil)
        NotificationCenter.default.addObserver(self,
                                               selector: #selector(keyboardWillHide(notification:)),
                                               name: NSNotification.Name.UIKeyboardWillHide, object: nil)
    }

    func keyboardWillShow(notification: NSNotification) {

        if let keyboardSize = (notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {
            let duration = notification.userInfo![UIKeyboardAnimationDurationUserInfoKey] as! Double
// if using constraints            
// bottomViewBottomSpaceConstraint.constant = keyboardSize.height
self.view.frame.origin.y -= keyboardSize.height
            UIView.animate(withDuration: duration) {
                self.view.layoutIfNeeded()
            }
        }
    }
    func keyboardWillHide(notification: NSNotification) {

        let duration = notification.userInfo![UIKeyboardAnimationDurationUserInfoKey] as! Double
//if using constraint
//        bottomViewBottomSpaceConstraint.constant = 0
self.view.frame.origin.y = 0
        UIView.animate(withDuration: duration) {
            self.view.layoutIfNeeded()
        }
    }

Don't forget to remove notifications at right place.

不要忘记在正确的位置删除通知。

func removeKeyboardNotifications() {
    NotificationCenter.default.removeObserver(self, name: NSNotification.Name.UIKeyboardWillShow, object: nil)
    NotificationCenter.default.removeObserver(self, name: NSNotification.Name.UIKeyboardWillHide, object: nil)
}

回答by KSR

#define DEVICE_HEIGHT [[UIScreen mainScreen] bounds].size.height       
 -(void)viewDidLoad {

            [super viewDidLoad];

         // 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

        {

        [super viewWillDisappear:animated];
            // unregister for keyboard notifications while not visible.

            [[NSNotificationCenter defaultCenter] removeObserver:self
                                                            name:UIKeyboardWillShowNotification
                                                          object:self.view.window];

            [[NSNotificationCenter defaultCenter] removeObserver:self
                                                            name:UIKeyboardWillHideNotification
                                                          object:self.view.window];
        }

    -(void)keyboardWillShow:(NSNotification *)noti

     {

        NSDictionary* userInfo = [noti userInfo];
        CGRect keyboardRect = [[userInfo objectForKey:UIKeyboardFrameEndUserInfoKey]   
        CGRectValue];
        keyboardRect = [self.view convertRect:keyboardRect fromView:nil];

        CGRect viewFrame = self.view.frame;
        viewFrame.size.height = DEVICE_HEIGHT - CGRectGetHeight(keyboardRect);

        [UIView beginAnimations:nil context:NULL];
        [UIView setAnimationDuration:0.1];
        [UIView setAnimationBeginsFromCurrentState:YES];
        self.view.frame = viewFrame;

        CGPoint bottomOffset = CGPointMake(0, self.scrollView.contentSize.height  
                               - self.view.bounds.size.height);
        [self.scrollView setContentOffset:bottomOffset animated:NO];

        [UIView commitAnimations];

    }

    -(void)keyboardWillHide:(NSNotification *)noti

     {

        NSDictionary* userInfo = [noti userInfo];
        CGRect keyboardRect = [[userInfo 
                       objectForKey:UIKeyboardFrameEndUserInfoKey]CGRectValue];

        keyboardRect = [self.view convertRect:keyboardRect fromView:nil];

        CGRect viewFrame = self.view.frame;
        viewFrame.size.height = DEVICE_HEIGHT;

        [UIView beginAnimations:nil context:NULL];
        [UIView setAnimationDuration:0.1];
        [UIView setAnimationBeginsFromCurrentState:YES];
        self.view.frame = viewFrame;
        [UIView commitAnimations];
    }