iphone - UItextview在iphone应用程序中上下移动（当键盘出现和消失时）

Question

当键盘出现和消失时，如何在 iPhone 应用程序中UItextview 上下移动。UIScrollView

Answer 1

一种方法是--->在viewDidLoad或ViewWillAppear添加这些观察者

NSNotificationCenter *center = [NSNotificationCenter defaultCenter];
[center addObserver:self selector:@selector(keyboardDisappeared) name:UIKeyboardWillHideNotification object:nil];
[center addObserver:self selector:@selector(keyboardAppeared) name:UIKeyboardWillShowNotification object:nil];

比写keyboardDisappeared和keyboardAppeared如下

-(void) keyboardDisappeared
{
    [UIView beginAnimations:@"animate" context:nil];
    [UIView setAnimationDuration:0.2f];
    [UIView setAnimationBeginsFromCurrentState: NO];
    self.view.frame = CGRectMake(self.view.frame.origin.x, self.view.frame.origin.y+100(same as you do in keyboardAppeared), self.view.frame.size.width, self.view.frame.size.height);
    [UIView commitAnimations];
}

-(void) keyboardAppeared
{
    [UIView beginAnimations:@"animate" context:nil];
    [UIView setAnimationDuration:0.2f];
    [UIView setAnimationBeginsFromCurrentState: NO];
    self.view.frame = CGRectMake(self.view.frame.origin.x, self.view.frame.origin.y-(as much you want), self.view.frame.size.width, self.view.frame.size.height);
    [UIView commitAnimations];
}

更新：

斯威夫特 3.x/4.x

添加这些观察者 -

    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)

和选择器方法：

@objc func keyboardWillShow(notification:NSNotification) {
    adjustView(show: true, notification: notification)
}

@objc func keyboardWillHide(notification:NSNotification) {
    adjustView(show: false, notification: notification)
}

func adjustView(show:Bool, notification:NSNotification) {
    var userInfo = notification.userInfo!
    let keyboardFrame:CGRect = (userInfo[UIKeyboardFrameBeginUserInfoKey] as! NSValue).cgRectValue
    let animationDurarion = userInfo[UIKeyboardAnimationDurationUserInfoKey] as! TimeInterval
    let changeInHeight = (keyboardFrame.size.height + 40/*or any value as per need*/) * (show ? 1 : -1)
    UIView.animate(withDuration: animationDurarion, animations: { () -> Void in
        // change height Constraint or change height with changeInHeight here to your UItextView/other view
    })

}

不要忘记删除观察者！！！

Answer 2

只需在-viewDidLoador中添加键盘操作的通知观察者-viewWillAppear:：

NSNotificationCenter * notificationCetner = [NSNotificationCenter defaultCenter];
[notificationCetner addObserver:self
                       selector:@selector(_keyboardWasShown:)
                           name:UIKeyboardDidShowNotification
                         object:nil];
[notificationCetner addObserver:self
                       selector:@selector(_keyboardWillHide:)
                           name:UIKeyboardWillHideNotification
                         object:nil];

-_keyboardWasShown:然后在&-_keyboardWillHide:方法中更新您的文本视图的框架。

Answer 3

有一个不错的库TPKeyboardAvoiding，你可以使用（在这里找到）。

或者，您可以自己编程并使用 的contentOffset属性UIScrollView向下或向上移动内容。然后你应该听键盘的keyboardDidShow和keyboardWillHide方法。

希望能帮助到你！

Answer 4

首先设置 textview 的委托，然后尝试实现这些方法....

    - (BOOL)textViewShouldBeginEditing:(UITextView *)textView
    {
        [self scrollViewToCenterOfScreen:textView];
        return YES;
    }

    - (void) scrollViewToCenterOfScreen:(UIView *)theView
    {
        CGFloat viewCenterY = theView.center.y;
        CGRect applicationFrame = [[UIScreen mainScreen] applicationFrame];

        CGFloat availableHeight = applicationFrame.size.height - 300;            // Remove area covered by keyboard

        CGFloat y = viewCenterY - availableHeight / 2.0;

        if (y < 0)
        {
            y = 0;
        }
        [scrollView setContentOffset:CGPointMake(0, y) animated:YES];
    }

// -------- Modified --------


    - (BOOL)textView:(UITextView *)txtView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)tempText
{
    if( [tempText rangeOfCharacterFromSet:[NSCharacterSet newlineCharacterSet]].location == NSNotFound )
    {
        return YES;
    }

    [txtView resignFirstResponder];
    [self.scrollView setContentOffset:CGPointMake(0.0f, 0.0f) animated:TRUE];
    return NO;
}