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

这里有很多答案,但这很有效,而且比大多数答案都短得多:

- (void)textFieldDidBeginEditing:(UITextField *)sender
{
    UIScrollView *scrollView = (UIScrollView *)self.view; // assuming this method is pasted into the UIScrollView's controller
    const double dontHardcodeTheKeyboardHeight = 162;
    double textY = [sender convertPoint:CGPointMake(0, 0) toView:scrollView].y;
    if (textY - scrollView.contentOffset.y + sender.frame.size.height > self.view.frame.size.height - dontHardcodeTheKeyboardHeight)
        [scrollView setContentOffset:CGPointMake(0.0, textY - 10) animated:YES];
}

其他回答

我在这里没有看到这种可能性,所以我添加了它,因为我尝试了答案中的方法,但几个小时后发现在iOS6/7中的XCode 5中有一种更简单的方法:使用NSLayoutConstraints。

请参见:自动布局约束-键盘

这是我的代码:

.m文件:

// Called when the UIKeyboardWillShowNotification is sent.
- (void)keyboardWillBeShown:(NSNotification*)aNotification
{
    NSLog(@"keyboardWillBeShown:");
    [self.PhoneNumberLabelOutlet setHidden:TRUE];
    CGFloat heightOfLabel = self.PhoneNumberLabelOutlet.frame.size.height;
    for( NSLayoutConstraint* thisConstraint in self.topElementsVerticalDistanceFromTopLayoutConstraint ) {
        thisConstraint.constant -= heightOfLabel;
    }

    NSDictionary* info = [aNotification userInfo];
    CGSize kbSize = [[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size;

    CGFloat oldConstant = [self.SignInYConstraint constant];
    self.SignInYConstraint.constant = oldConstant + kbSize.height;
    [self.view setNeedsUpdateConstraints];

    NSTimeInterval duration = [[info objectForKey:UIKeyboardAnimationDurationUserInfoKey] doubleValue];
    [UIView animateWithDuration:duration animations:^{
        [self.view layoutIfNeeded];
    }];

}

.h文件:

#import <UIKit/UIKit.h>

@interface SignInViewController : UIViewController {

    UITextField* _activeField;
}




- (void)signInCallback:(NSObject*)object;


@property (weak, nonatomic) IBOutlet UILabel *PhoneNumberLabelOutlet;

@property (weak, nonatomic) IBOutlet UIActivityIndicatorView *ActivityIndicatorOutlet;

@property (weak, nonatomic) IBOutlet UITextField *UserIDTextfieldOutlet;

@property (weak, nonatomic) IBOutlet UITextField *PasswordTextfieldOutlet;

@property (weak, nonatomic) IBOutlet UIButton *SignInButton;

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

@property (strong, nonatomic) IBOutletCollection(NSLayoutConstraint) NSArray *topElementsVerticalDistanceFromTopLayoutConstraint;

@end

参考以下内容

import UIKit
@available(tvOS, unavailable)
public class KeyboardLayoutConstraint: NSLayoutConstraint {

    private var offset : CGFloat = 0
    private var keyboardVisibleHeight : CGFloat = 0

    @available(tvOS, unavailable)
    override public func awakeFromNib() {
        super.awakeFromNib()

        offset = constant

        NotificationCenter.default.addObserver(self, selector: #selector(KeyboardLayoutConstraint.keyboardWillShowNotification(_:)), name: NSNotification.Name.UIKeyboardWillShow, object: nil)
        NotificationCenter.default.addObserver(self, selector: #selector(KeyboardLayoutConstraint.keyboardWillHideNotification(_:)), name: NSNotification.Name.UIKeyboardWillHide, object: nil)
    }

    deinit {
        NotificationCenter.default.removeObserver(self)
    }

    // MARK: Notification

    @objc func keyboardWillShowNotification(_ notification: Notification) {
        if let userInfo = notification.userInfo {
            if let frameValue = userInfo[UIKeyboardFrameEndUserInfoKey] as? NSValue {
                let frame = frameValue.cgRectValue
                keyboardVisibleHeight = frame.size.height
            }

            self.updateConstant()
            switch (userInfo[UIKeyboardAnimationDurationUserInfoKey] as? NSNumber, userInfo[UIKeyboardAnimationCurveUserInfoKey] as? NSNumber) {
            case let (.some(duration), .some(curve)):

                let options = UIViewAnimationOptions(rawValue: curve.uintValue)

                UIView.animate(
                    withDuration: TimeInterval(duration.doubleValue),
                    delay: 0,
                    options: options,
                    animations: {
                        UIApplication.shared.keyWindow?.layoutIfNeeded()
                        return
                    }, completion: { finished in
                })
            default:

                break
            }

        }

    }

    @objc func keyboardWillHideNotification(_ notification: NSNotification) {
        keyboardVisibleHeight = 0
        self.updateConstant()

        if let userInfo = notification.userInfo {

            switch (userInfo[UIKeyboardAnimationDurationUserInfoKey] as? NSNumber, userInfo[UIKeyboardAnimationCurveUserInfoKey] as? NSNumber) {
            case let (.some(duration), .some(curve)):

                let options = UIViewAnimationOptions(rawValue: curve.uintValue)

                UIView.animate(
                    withDuration: TimeInterval(duration.doubleValue),
                    delay: 0,
                    options: options,
                    animations: {
                        UIApplication.shared.keyWindow?.layoutIfNeeded()
                        return
                    }, completion: { finished in
                })
            default:
                break
            }
        }
    }

    func updateConstant() {
        self.constant = offset + keyboardVisibleHeight
    }

}

仅使用文本字段:

1a)使用界面生成器:选择所有文本字段=>编辑=>嵌入=>滚动视图

1b)在UIScrollView中手动嵌入文本字段,称为scrollView

2) 设置UITextFieldDelegate

3) 设置每个textField.delegate=self;(或在Interface Builder中建立连接)

4) 复制/粘贴:

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

- (void)textFieldDidEndEditing:(UITextField *)textField {
    [scrollView setContentOffset:CGPointZero animated:YES];
}

如果该文本字段位于表的单元格中(即使table.scrollable=NO),也可以轻松自动完成。

注意:桌子的位置和大小必须合理。例如:如果桌子的y位置是从视图底部算起的100,那么300高的键盘将覆盖整个桌子。如果表的高度为10,并且当键盘出现时,其中的文本字段必须向上滚动100才能可见,那么该文本字段将超出表的范围。

扩展UIViewController的简单解决方案

https://github.com/damienromito/VisibleFormViewController