UIScrollView内容插件不适用于键盘高度 [英] UIScrollView Content Insets not working for Keyboard Height

问题描述

当键盘隐藏 UITextField 时，我试图通过使用<$更改大小来移动 UIScrollView c $ c> contentInsets 如图所示。

I am trying to move a UIScrollView when the keyboard hides a UITextField by changing the size using the contentInsets as it is shown.

然而，它不适用于键盘高度。键盘高度为216，但如果我将iPhone底部插图设置为515（iPhone纵向模式）和310设置为iPhone横向模式，它只会停止在正确位置滚动。为什么这些尺寸会如此不同？我不想硬编码这些任意值。

However, it's not working for the keyboard height. The keyboard height comes as 216, but it only stops scrolling at the correct location if I set the bottom inset to 515 for iPhone portrait mode and 310 for iPhone landscape mode. Why would these dimensions be so different? I don't want to hardcode these arbitrary values in.

- (void)viewDidLoad
{
    [super viewDidLoad];
    self.view.frame = self.parentViewController.view.frame;

    [self.textView becomeFirstResponder];

    NSLog(@"scrollview: %f,%f, parent: %f,%f", self.view.frame.size.height, self.view.frame.size.width, self.parentViewController.view.frame.size.height, self.parentViewController.view.frame.size.width);

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

- (void)keyboardWasShown:(NSNotification *)notification
{
    if([[UIDevice currentDevice]userInterfaceIdiom]==UIUserInterfaceIdiomPhone) {

        // Step 1: Get the size of the keyboard.
        CGFloat keyboardHeight = [[[notification userInfo] objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size.height;

        // Step 2: Adjust the bottom content inset of your scroll view by the keyboard height.
        UIEdgeInsets contentInsets = UIEdgeInsetsMake(0.0, 0.0, keyboardHeight, 0.0);
        ((UIScrollView*)self.view).contentInset = contentInsets;
        ((UIScrollView*)self.view).scrollIndicatorInsets = contentInsets;

        // Step 3: Scroll the target text field into view.
        CGRect aRect = self.view.frame;
        aRect.size.height = aRect.size.height - keyboardHeight;
        if (!CGRectContainsPoint(aRect, self.textView.frame.origin) ) {
            CGPoint scrollPoint = CGPointMake(0.0, self.textView.frame.origin.y - keyboardHeight);
            [((UIScrollView*)self.view) setContentOffset:scrollPoint animated:YES];
        }
    }
}

- (void) keyboardWillHide:(NSNotification *)notification {
    UIEdgeInsets contentInsets = UIEdgeInsetsZero;
    ((UIScrollView*)self.view).contentInset = contentInsets;
    ((UIScrollView*)self.view).scrollIndicatorInsets = contentInsets;
}

编辑：

在键盘打开之前，我将其打印出来：

Before the keyboard is open, i print this out:

NSLog(@"scrollview: %f,%f, parent: %f,%f", self.view.frame.size.height, self.view.frame.size.width, self.parentViewController.view.frame.size.height, self.parentViewController.view.frame.size.width);

并打印出来：

scrollview: 431.000000,320.000000, parent: 431.000000,320.000000

推荐答案

我认为主要问题是您需要使用 UIKeyboardFrameEndUserInfoKey 而不是 UIKeyboardFrameBeginUserInfoKey 。

I think that the main issue is that you need to use UIKeyboardFrameEndUserInfoKey instead of UIKeyboardFrameBeginUserInfoKey.

话虽这么说，我写了一个不同版本的方法，即使滚动视图没有放在屏幕的底部也可以工作你：

That being said, I have written a different version of this method that will work even if the scrollview is not placed at the bottom of the screen and may work better for you:

请注意，我使用 self.activeTextField 而不是 self.textField 。

Note that I use self.activeTextField instead of self.textField.

// Called when the UIKeyboardDidShowNotification is sent.
- (void)keyboardWasShown:(NSNotification*)aNotification
{
    // Calculate the frame of the scrollview, in self.view's coordinate system
    UIScrollView *scrollView    = self.scrollView;
    CGRect scrollViewRect       = [self.view convertRect:scrollView.frame fromView:scrollView.superview];

    // Calculate the frame of the keyboard, in self.view's coordinate system
    NSDictionary* info          = [aNotification userInfo];
    CGRect kbRect               = [[info objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue];
    kbRect                      = [self.view convertRect:kbRect fromView:nil];

    // Figure out where the two frames overlap, and set the content offset of the scrollview appropriately
    CGRect hiddenScrollViewRect = CGRectIntersection(scrollViewRect, kbRect);
    if (!CGRectIsNull(hiddenScrollViewRect))
    {
        UIEdgeInsets contentInsets       = UIEdgeInsetsMake(0.0,  0.0, hiddenScrollViewRect.size.height,  0.0);
        scrollView.contentInset          = contentInsets;
        scrollView.scrollIndicatorInsets = contentInsets;
    }

    [self scrollToActiveTextField];
}

// Called when the UIKeyboardWillHideNotification is sent
- (void)keyboardWillBeHidden:(NSNotification*)aNotification
{
    self.scrollView.contentInset          = UIEdgeInsetsZero;
    self.scrollView.scrollIndicatorInsets = UIEdgeInsetsZero;
}

- (void)scrollToActiveTextField
{
    if (self.activeTextField)
    {
        CGRect visibleRect = self.activeTextField.frame;
        visibleRect        = [self.scrollView convertRect:visibleRect fromView:self.activeTextField.superview];
        visibleRect        = CGRectInset(visibleRect, 0.0f, -5.0f);
        [self.scrollView scrollRectToVisible:visibleRect animated:YES];
    }
}

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