0

我正在编写一个针对 iOS 6.1 的应用程序。如果 UITextField 被键盘遮挡，我正在尝试遵循这个Apple 文档，了解如何将它滚动到视图中。问题是 Apple 记录的用于计算滚动点的算法效果不佳。我计算滚动点的算法效果稍好一些，但相差 70 像素。计算滚动点的正确方法是什么？

下面你可以看到，从左到右，我的键盘显示之前的视图，滚动后的视图使用Apple的算法计算滚动点，滚动后的视图使用我的算法计算滚动点。（该网格中的每个正方形都是 25 像素 x 25 像素。）

在此处输入图像描述

这是我正在使用的代码。注意#if APPLE_WAY块。

- (void)keyboardWasShown:(NSNotification*)aNotification
{
    NSDictionary* info = [aNotification userInfo];
    CGSize kbSize = [[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size;

    UIEdgeInsets contentInsets = UIEdgeInsetsMake(0.0, 0.0, kbSize.height, 0.0);
    self.view.contentInset = contentInsets;
    self.view.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;
    if (!CGRectContainsPoint(aRect, self.activeField.frame.origin) ) {

#if APPLE_WAY
        CGPoint scrollPoint = CGPointMake(0.0, self.activeField.frame.origin.y-kbSize.height);
#else
        CGFloat offset = self.activeField.frame.origin.y;

        //TODO: Why is this off by 70?
        offset = offset - 70;

        CGPoint scrollPoint = CGPointMake(0.0, offset);
#endif
        [self.view setContentOffset:scrollPoint animated:YES];
    }
}
4

3 回答 3

2

您只需将偏移量设置为键盘的高度：

CGFloat offset = kbSize.height;
CGPoint scrollPoint = CGPointMake(0.0, offset);
[self.view setContentOffset:scrollPoint animated:YES];

希望这可以帮助

于 2013-04-04T04:10:02.543 回答
1

有几种方法可以做到这一点。鉴于你的情况，我会做这样的事情：

- (void)keyboardWasShown:(NSNotification *)aNotification
{
    NSDictionary* info = [aNotification userInfo];
    CGSize kbSize = [[info objectForKey:UIKeyboardFrameBeginUserInfoKey] 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;
    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];
    }
}

- (void)keyboardWillBeHidden:(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;

    CGRect aRect = self.view.frame;
    aRect.size.height -= kbSize.height;
    if (!CGRectContainsPoint(aRect, self.activeField.frame.origin) ) {
        CGPoint scrollPoint = CGPointMake(0, 0);
        [self.scrollView setContentOffset:scrollPoint animated:YES];
    }
}

然后，在您的 viewDidLoad 方法中：

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

[[NSNotificationCenter defaultCenter] addObserver:self
                                         selector:@selector(keyboardWillBeHidden:)
                                             name:UIKeyboardWillHideNotification object:nil];
于 2013-04-04T04:17:29.940 回答
0

当您拥有的是滚动视图时，这很容易，因为您甚至不必滚动；您所要做的就是调整 contentInset 和 scrollIndicatorInsets 以避开键盘，其余的会自动发生：

- (void) keyboardShow: (NSNotification*) n {
    self->_oldContentInset = self.scrollView.contentInset;
    self->_oldIndicatorInset = self.scrollView.scrollIndicatorInsets;
    self->_oldOffset = self.scrollView.contentOffset;
    NSDictionary* d = [n userInfo];
    CGRect r = [[d objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue];
    r = [self.scrollView convertRect:r fromView:nil];
    CGRect f = self.fr.frame;
    CGFloat y =
        CGRectGetMaxY(f) + r.size.height -
            self.scrollView.bounds.size.height + 5;
    if (r.origin.y < CGRectGetMaxY(f))
        [self.scrollView setContentOffset:CGPointMake(0, y) animated:YES];
    UIEdgeInsets insets;
    insets = self.scrollView.contentInset;
    insets.bottom = r.size.height;
    self.scrollView.contentInset = insets;
    insets = self.scrollView.scrollIndicatorInsets;
    insets.bottom = r.size.height;
    self.scrollView.scrollIndicatorInsets = insets;
}

在本书的这一部分，我给出了一堆不同的策略和代码：

http://www.aeth.com/iOSBook/ch23.html#_keyboard_covers_text_field

所有这些都得到了可下载项目的支持，您可以在我的 github 站点上获取这些项目。

于 2013-04-04T04:29:39.990 回答