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

使用ViewModifier快速切换UI

可以使用SwiftUI的ViewModifier。这要简单得多。

import SwiftUI
import Combine

struct KeyboardAwareModifier: ViewModifier {
    @State private var keyboardHeight: CGFloat = 0

    private var keyboardHeightPublisher: AnyPublisher<CGFloat, Never> {
        Publishers.Merge(
            NotificationCenter.default
                .publisher(for: UIResponder.keyboardWillShowNotification)
                .compactMap { $0.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue }
                .map { $0.cgRectValue.height },
            NotificationCenter.default
                .publisher(for: UIResponder.keyboardWillHideNotification)
                .map { _ in CGFloat(0) }
       ).eraseToAnyPublisher()
    }

    func body(content: Content) -> some View {
        content
            .padding(.bottom, keyboardHeight)
            .onReceive(keyboardHeightPublisher) { self.keyboardHeight = $0 }
    }
}

extension View {
    func KeyboardAwarePadding() -> some View {
        ModifiedContent(content: self, modifier: KeyboardAwareModifier())
    }
}

在你看来

struct SomeView: View {
    @State private var someText: String = ""

    var body: some View {
        VStack {
            Spacer()
            TextField("some text", text: $someText)
        }.KeyboardAwarePadding()
    }
}

KeyboardAwarePadding()将自动为视图添加填充。它更优雅。

其他回答

这里是一个免费的库,用于iPhone应用程序中的键盘处理键盘处理。你只需要写一行代码:

[AutoScroller addAutoScrollTo:scrollView];

处理表单中的键盘非常棒

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。

需要考虑的一件事是,您是否希望单独使用UITextField。我还没有遇到任何设计良好的iPhone应用程序在UITableViewCells之外实际使用UITextFields。

这将是一些额外的工作,但我建议您实现表视图中的所有数据条目视图。将UITextView添加到UITableViewCells。

请遵循以下步骤。

1) 在.h文件中声明以下变量。

  {      
         CGFloat animatedDistance;
  }

2) 在.m文件中声明以下常量。

  static const CGFloat KEYBOARD_ANIMATION_DURATION = 0.3;
  static const CGFloat MINIMUM_SCROLL_FRACTION = 0.2;
  static const CGFloat MAXIMUM_SCROLL_FRACTION = 0.8;
  static const CGFloat PORTRAIT_KEYBOARD_HEIGHT = 216;
  static const CGFloat LANDSCAPE_KEYBOARD_HEIGHT = 162;

3) 使用UITextField代理向上/向下移动键盘。

  -(void) textFieldDidBeginEditing:(UITextField *)textField
  { 
         if(UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPhone)
         {
               CGRect textFieldRect = [self.view.window convertRect:textField.bounds fromView:textField];
               CGRect viewRect = [self.view.window convertRect:self.view.bounds fromView:self.view];

               CGFloat midline = textFieldRect.origin.y + 0.5 * textFieldRect.size.height;
               CGFloat numerator =
    midline - viewRect.origin.y
    - MINIMUM_SCROLL_FRACTION * viewRect.size.height;
               CGFloat denominator =
    (MAXIMUM_SCROLL_FRACTION - MINIMUM_SCROLL_FRACTION)
    * viewRect.size.height;
               CGFloat heightFraction = numerator / denominator;

               if (heightFraction < 0.0)
               {
                     heightFraction = 0.0;
               }
               else if (heightFraction > 1.0)
               {
                     heightFraction = 1.0;
               }

               UIInterfaceOrientation orientation =
    [[UIApplication sharedApplication] statusBarOrientation];
               if (orientation == UIInterfaceOrientationPortrait)
               {
                     animatedDistance = floor(PORTRAIT_KEYBOARD_HEIGHT * heightFraction);
               }
               else
               {
                     animatedDistance = floor(LANDSCAPE_KEYBOARD_HEIGHT * heightFraction);
               }

               CGRect viewFrame = self.view.frame;
               viewFrame.origin.y -= animatedDistance;

               [UIView beginAnimations:nil context:NULL];
               [UIView setAnimationBeginsFromCurrentState:YES];
               [UIView setAnimationDuration:KEYBOARD_ANIMATION_DURATION];

               [self.view setFrame:viewFrame];

               [UIView commitAnimations];
       }
  }

  -(void) textFieldDidEndEditing:(UITextField *)textField
  {
       if(UI_USER_INTERFACE_IDIOM()==UIUserInterfaceIdiomPhone)
       {
             CGRect viewFrame = self.view.frame;
             viewFrame.origin.y += animatedDistance;

             [UIView beginAnimations:nil context:NULL];
             [UIView setAnimationBeginsFromCurrentState:YES];
             [UIView setAnimationDuration:KEYBOARD_ANIMATION_DURATION];

             [self.view setFrame:viewFrame];

             [UIView commitAnimations];
       }
 }

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