ios - 显示键盘时尝试向上移动 View

Question

我试图在显示键盘时将我的 View 向上推(它覆盖了我希望用户在打字时看到的数据。我正在使用此代码:

KBKeyboardHandler.h:

@protocol KBKeyboardHandlerDelegate;

@interface KBKeyboardHandler : NSObject

- (id)init;

// Put 'weak' instead of 'assign' if you use ARC
@property(nonatomic, assign) id<KBKeyboardHandlerDelegate> delegate; 
@property(nonatomic) CGRect frame;

@end

KBKeyboardHandler.m:

#import "KBKeyboardHandler.h"
#import "KBKeyboardHandlerDelegate.h"

@implementation KBKeyboardHandler

- (id)init
{
    self = [super init];
    if (self)
    {
        [[NSNotificationCenter defaultCenter] addObserver:self
                                                 selector:@selector(keyboardWillShow:)
                                                     name:UIKeyboardWillShowNotification
                                                   object:nil];

        [[NSNotificationCenter defaultCenter] addObserver:self
                                                 selector:@selector(keyboardWillHide:)
                                                     name:UIKeyboardWillHideNotification
                                                   object:nil];
    }

    return self;
}

- (void)dealloc
{
    [[NSNotificationCenter defaultCenter] removeObserver:self];
    [super dealloc];
}

@synthesize delegate;
@synthesize frame;

- (void)keyboardWillShow:(NSNotification *)notification
{
    CGRect oldFrame = self.frame;    
    [self retrieveFrameFromNotification:notification];

    if (oldFrame.size.height != self.frame.size.height)
    {
        CGSize delta = CGSizeMake(self.frame.size.width - oldFrame.size.width,
                                  self.frame.size.height - oldFrame.size.height);
        if (self.delegate)
            [self notifySizeChanged:delta notification:notification];
    }
}

- (void)keyboardWillHide:(NSNotification *)notification
{
    if (self.frame.size.height > 0.0)
    {
        [self retrieveFrameFromNotification:notification];
        CGSize delta = CGSizeMake(-self.frame.size.width, -self.frame.size.height);

        if (self.delegate)
            [self notifySizeChanged:delta notification:notification];
    }

    self.frame = CGRectZero;
}

- (void)retrieveFrameFromNotification:(NSNotification *)notification
{
    CGRect keyboardRect;
    [[[notification userInfo] objectForKey:UIKeyboardFrameEndUserInfoKey] getValue:&keyboardRect];
    self.frame = [[UIApplication sharedApplication].keyWindow.rootViewController.view convertRect:keyboardRect fromView:nil];
}

- (void)notifySizeChanged:(CGSize)delta notification:(NSNotification *)notification
{
    NSDictionary *info = [notification userInfo];

    UIViewAnimationCurve curve;
    [[info objectForKey:UIKeyboardAnimationCurveUserInfoKey] getValue:&curve];

    NSTimeInterval duration;
    [[info objectForKey:UIKeyboardAnimationDurationUserInfoKey] getValue:&duration];

    void (^action)(void) = ^{
        [self.delegate keyboardSizeChanged:delta];
    };

    [UIView animateWithDuration:duration
                          delay:0.0
                        options:curve
                     animations:action
                     completion:nil];    
}

@end

KBKeyboardHandlerDelegate.h:

@protocol KBKeyboardHandlerDelegate

- (void)keyboardSizeChanged:(CGSize)delta;

@end

示例MyViewController.h:

@interface MyViewController : UIViewController<KBKeyboardHandlerDelegate>
...
@end

示例MyViewController.m:

@implementation MyViewController
{
    KBKeyboardHandler *keyboard;
}

- (void)dealloc
{
    keyboard.delegate = nil;
    [keyboard release];
    [super dealloc];
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    keyboard = [[KBKeyboardHandler alloc] init];
    keyboard.delegate = self;
}

- (void)viewDidUnload
{
    [super viewDidUnload];
    keyboard.delegate = nil;
    [keyboard release];
    keyboard = nil;
}

- (void)keyboardSizeChanged:(CGSize)delta
{
    // Resize / reposition your views here. All actions performed here 
    // will appear animated.
    // delta is the difference between the previous size of the keyboard 
    // and the new one.
    // For instance when the keyboard is shown, 
    // delta may has width=768, height=264,
    // when the keyboard is hidden: width=-768, height=-264.
    // Use keyboard.frame.size to get the real keyboard size.

    // Sample:
    CGRect frame = self.view.frame;
    frame.size.height -= delta.height;
    self.view.frame = frame;
}

我找到了 here .我想弄清楚为什么我的观点没有被推高。键盘正在显示并且 keyboardSizeChanged 已启动，但 View 没有移动。我打开了一个新项目并将 KBKeyboardHandler 和委托(delegate)文件复制到其中，实现了代码，在新项目中它工作正常，所以我知道这是我原来项目中的一些东西搞砸了。知道它可能是什么吗？

Answer 1

如果您不使用 UITableView，请使用 UIScrollView 作为元素的父 View 并添加以下代码根据需要调整，

您将需要一个 NSObjects 的 NSArray，我将其命名为 scrollToObjects，并在 viewDidLoad 中将元素添加到需要滚动的数组中，这样当调用 keyboardWasShown 时，您可以检查是否应滚动到当前选定的元素。

我使用 self.activeField 来存储我当前选择的元素，该元素是在元素触发事件时设置的(该事件需要是第一个被调用的事件之一，并且总是被调用)

然后我检查 scrollToObjects 是否包含 activeField 以及它是否向上滚动 UIScrollView 然后在 activeField resignsFirstResponder 时向下滚动

// Call this method somewhere in your view controller setup code.
- (void)registerForKeyboardNotifications
{
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWasShown:) name:UIKeyboardWillShowNotification object:nil];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillBeHidden:) name:UIKeyboardWillHideNotification object:nil];
}

// Called when the UIKeyboardDidShowNotification is sent.
- (void)keyboardWasShown:(NSNotification*)aNotification
{
    NSDictionary* info = [aNotification userInfo];
    CGSize kbSize = [[info objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue].size;

    UIEdgeInsets contentInsets = UIEdgeInsetsMake(0.0, 0.0, kbSize.height, 0.0);
    self.scrollView.contentInset = contentInsets;
    self.scrollView.scrollIndicatorInsets = contentInsets;

    // If active text field is hidden by keyboard, scroll it so it's visible
    // Your application might not need or want this behavior.
    CGRect aRect = self.view.frame;
    aRect.size.height -= kbSize.height;
    // Wouldn't go true so used an array that contains text fields that need to be scrolled   to
    //    if (!CGRectContainsPoint(aRect, self.activeField.frame.origin) ) {
    //        CGPoint scrollPoint = CGPointMake(0.0, self.activeField.frame.origin.y-    kbSize.height);
    //        [self.scrollView setContentOffset:scrollPoint animated:YES];
    //    }
    if ([self.scrollToObjects containsObject:self.activeField]) {
        CGPoint scrollPoint = CGPointMake(0.0, self.activeField.frame.origin.y+    (self.activeField.frame.size.height*2)-kbSize.height);
        [self.scrollView setContentOffset:scrollPoint animated:YES];
    }
}

// Called when the UIKeyboardWillHideNotification is sent 
- (void)keyboardWillBeHidden:(NSNotification*)aNotification
{ 
    // self.scrollView.contentInset = UIEdgeInsetsZero;
    [self.scrollView setContentOffset:CGPointMake(0.0, 0.0) animated:YES];
    self.scrollView.scrollIndicatorInsets = UIEdgeInsetsZero;
}

一个更简单的解决方案是使用以下代码或类似于对象的激活和停用的东西来处理下面的 UITextFieldDelegate 方法

-(void)textFieldDidBeginEditing:(UITextField *)textField
{
    CGPoint scrollPoint = CGPointMake(0.0, textField.frame.origin.y);
    [self.theScrollView setContentOffset:scrollPoint animated:YES];
}

-(void)textFieldDidEndEditing:(UITextField *)textField
{
    [self.theScrollView setContentOffset:CGPointMake(0.0, 0.0) animated:YES];
    self.theScrollView.scrollIndicatorInsets = UIEdgeInsetsZero;
}