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

您也可以使用textfield委托方法。检查以下代码。当将文本字段放在滚动视图上时,它对我很有用。

- (void)textFieldDidBeginEditing:(UITextField *)textField
{
     if(textField == answer)
    {   
         CGPoint cPoint = textField.frame.origin;
         [scrollView setContentOffset:CGPointMake(0, cPoint.y - 100) animated:YES];
    }
}

注意:您必须根据视图更改cPoint.y-100值。

其他回答

我最近发现自己在开发消息应用程序时也遇到了类似的情况。我创建了一个自定义的UIView,它粘在键盘顶部,并自动完成您所需的大部分操作

消息生成器视图

(来源:thegamengine.org)

这个项目背后的想法是创建类似于iMessage合成视图AKA的功能:

当键盘关闭时,会粘在键盘顶部并移动到屏幕底部处理文本中的更改控制柄旋转

为了调整/重新配置UIScrollView,您需要使用以下可选委托方法:

-(void)messageComposerFrameDidChange:(CGRect)帧,动画持续时间:(float)持续时间;

每当更改帧(调整大小、重新定位、旋转)时都会调用它,并且还会提供动画持续时间。您可以根据需要使用此信息调整UIScrollView的框架和内容插图的大小。

试试这个小把戏。

- (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 = textField.frame.origin.y / 2; // tweak as needed
    const float movementDuration = 0.3f; // tweak as needed

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

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

我使用Swift和自动布局(但不能评论之前的Swift答案);以下是我在没有滚动视图的情况下的操作方法:

我在IB中使用字段之间的垂直约束来布局表单,以分隔它们。我在容器视图的最顶部字段中添加了一个垂直约束,并为此创建了一个出口(下面代码中的topSpaceForFormConstraint)。所有需要的就是更新这个约束,这是我在动画块中为一个漂亮的软运动所做的。当然,高度检查是可选的,在这种情况下,我只需要对最小的屏幕尺寸进行检查。

这可以使用任何常用的textFieldDidBegginEditing或keyboardWillShow方法调用。

func setFormHeight(top: CGFloat)
{
    let height = UIScreen.mainScreen().bounds.size.height

    // restore text input fields for iPhone 4/4s
    if (height < 568) {
        UIView.animateWithDuration(0.2, delay: 0.0, options: nil, animations: {
            self.topSpaceForFormConstraint.constant = top
            self.view.layoutIfNeeded()
            }, completion: nil)
    }

}

对于Swift Developer,使用Swift 3,这里是回购https://github.com/jamesrochabrun/KeyboardWillShow

import UIKit

class ViewController: UIViewController {

    //1 Create a view that will hold your TEXTFIELD
    let textField: UITextField = {
        let tf = UITextField()
        tf.translatesAutoresizingMaskIntoConstraints = false
        tf.layer.borderColor = UIColor.darkGray.cgColor
        tf.layer.borderWidth = 3.0
        return tf
    }()
    //2 global variable that will hold the bottom constraint on changes
    var textfieldBottomAnchor: NSLayoutConstraint?

    override func viewDidLoad() {
        super.viewDidLoad()
        //3 add the view to your controller
        view.addSubview(textField)
        textField.heightAnchor.constraint(equalToConstant: 80).isActive = true
        textField.widthAnchor.constraint(equalToConstant: view.frame.width).isActive = true
        textField.leftAnchor.constraint(equalTo: view.leftAnchor).isActive = true
        textfieldBottomAnchor = textField.bottomAnchor.constraint(equalTo: view.bottomAnchor)
        textfieldBottomAnchor?.isActive = true

        setUpKeyBoardObservers()
    }
    //4 Use NSnotificationCenter to monitor the keyboard updates
    func setUpKeyBoardObservers() {
        NotificationCenter.default.addObserver(self, selector: #selector(handleKeyboardWillShow), name: NSNotification.Name.UIKeyboardWillShow, object: nil)
        NotificationCenter.default.addObserver(self, selector: #selector(handleKeyboardWillHide), name: NSNotification.Name.UIKeyboardWillHide, object: nil)
    }

    //5 toggle the bottom layout global variable based on the keyboard's height
    func handleKeyboardWillShow(notification: NSNotification) {

        let keyboardFrame = notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as? CGRect
        if let keyboardFrame = keyboardFrame {
            textfieldBottomAnchor?.constant = -keyboardFrame.height
        }
        let keyboardDuration = notification.userInfo?[UIKeyboardAnimationDurationUserInfoKey] as? Double
        if let keyboardDuration = keyboardDuration {
            UIView.animate(withDuration: keyboardDuration, animations: {
                self.view.layoutIfNeeded()
            })
        }
    }

    func handleKeyboardWillHide(notification: NSNotification) {

        textfieldBottomAnchor?.constant = 0
        let keyboardDuration = notification.userInfo?[UIKeyboardAnimationDurationUserInfoKey] as? Double
        if let keyboardDuration = keyboardDuration {
            UIView.animate(withDuration: keyboardDuration, animations: {
                self.view.layoutIfNeeded()
            })
        }
    }
    //6 remove the observers
    override func viewDidDisappear(_ animated: Bool) {
        super.viewDidDisappear(animated)

        NotificationCenter.default.removeObserver(self)
    }
}

简单的解决方案和最新的动画api。将origin.y更改215,您可以将其自定义为适合您的值。

- (void)textFieldDidBeginEditing:(UITextField *)textField
{
    if (self.view.frame.origin.y >= 0) {

        [UIView animateWithDuration:0.5 animations:^{
           self.view.frame = CGRectMake(self.view.frame.origin.x, self.view.frame.origin.y-215, self.view.frame.size.width, self.view.frame.size.height);
       }];
   }
}

- (void)textFieldDidEndEditing:(UITextField *)textField
{
    if (self.view.frame.origin.y < 0) {
        [UIView animateWithDuration:0.5 animations:^{
           self.view.frame = CGRectMake(self.view.frame.origin.x, self.view.frame.origin.y+215, self.view.frame.size.width, self.view.frame.size.height);
        }];

    }
}