当方向改变时,如何定位UIScrollView使键盘变形

Question

我有一个UIScrollView设计用于在键盘启动时启用滚动功能.在纵向模式下滚动视图的定位很好; 我已将它定位在Interface Builder中,并contentSize在我的代码中设置...

CGSize scrollContentSize = CGSizeMake(360, 221);
self.scrollView.contentSize = scrollContentSize;

但是,我正在努力弄清楚如何改变位置,scrollview以便当方向改变为横向(和背面)时它有效地工作.我是否需要在Interface Builder中将其放置在横向(？)中,然后根据方向更改我的代码中的内容大小？

编辑:我得到键盘大小如下,并更改内容大小.当我移动到肖像时,这可以工作,但在横向模式下框架的位置略有错误.

 (void)keyboardWillShow:(NSNotification *)n{

    if (keyboardIsShown) {
    return;
    }

    NSDictionary* userInfo = [n userInfo];

    CGRect _keyboardEndFrame;
    [[userInfo valueForKey:UIKeyboardFrameEndUserInfoKey] getValue:&_keyboardEndFrame];
    CGFloat _keyboardHeight;
    UIDeviceOrientation orientation = [[UIDevice currentDevice] orientation];
    if (orientation == UIDeviceOrientationPortrait || orientation == UIDeviceOrientationPortraitUpsideDown) {
    _keyboardHeight = _keyboardEndFrame.size.height;
    }
    else {
        _keyboardHeight = _keyboardEndFrame.size.width;
    }

    // resize the noteView
    CGRect viewFrame = self.scrollView.frame;
     viewFrame.size.height -= _keyboardHeight;

    if (UIDeviceOrientationIsPortrait(orientation)){
        CGSize scrollContentSize = CGSizeMake(360, 221);
        self.scrollView.contentSize = scrollContentSize;
    }
    else if (UIDeviceOrientationIsLandscape(orientation)){
        CGSize scrollContentSize = CGSizeMake(520, 275);
        self.scrollView.contentSize = scrollContentSize;
    }

    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationBeginsFromCurrentState:YES];
    [UIView setAnimationDuration:0.3];
    [self.scrollView setFrame:viewFrame];
    [UIView commitAnimations];

    keyboardIsShown = YES;
}

Answer 1

你想要做的是弄清楚键盘顶部相对于包含scrollView的视图的位置.幸运的是,在UIView中有一个函数被调用convertRect:fromView:,它将从一个坐标系中取出框架并将其映射到另一个坐标系.在您的情况下,您知道键盘相对于主窗口的框架,但想知道键盘顶部相对于包含scrollView的视图的位置.一旦知道键盘顶部与视图相交的位置,就可以修改scrollView的高度以适应.

下面是我使用的代码片段,我在网上找到了一些代码并且不予以赞扬.在视图控制器中,您希望收到键盘显示和隐藏事件的通知:

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

然后执行keyboardWillShow:并keyboardWillHide:像这样:

// When the keyboard shows resize self.textView to touch the top of the keyboard.
-(void)keyboardWillShow:(NSNotification *)_notification {
    NSDictionary  *userInfo = [_notification userInfo];

    NSTimeInterval animationDuration;
    UIViewAnimationCurve animationCurve;
    CGRect keyboardEndFrame;
    [[userInfo objectForKey:UIKeyboardAnimationCurveUserInfoKey] getValue:&animationCurve];
    [[userInfo objectForKey:UIKeyboardAnimationDurationUserInfoKey] getValue:&animationDuration];
    [[userInfo objectForKey:UIKeyboardFrameEndUserInfoKey] getValue:&keyboardEndFrame];

        // Here we figure out where the keyboard overlaps with self.view
        // self.view contains self.textView
    CGRect keyboardFrame = [self.view convertRect:keyboardEndFrame fromView:nil];
    CGFloat textViewWidth = self.view.frame.size.width;

    [UIView beginAnimations:nil context:nil];
    [UIView setAnimationDuration:animationDuration];
    [UIView setAnimationCurve:animationCurve];
    self.textView.frame = CGRectMake(0, 0, textViewWidth, keyboardFrame.origin.y);
    [UIView commitAnimations];
}

// When the keyboard hides return self.textView to fullscreen
-(void)keyboardWillHide:(NSNotification *)_notification {
    NSDictionary  *userInfo = [_notification userInfo];

    NSTimeInterval animationDuration;
    UIViewAnimationCurve animationCurve;
    CGRect keyboardEndFrame;
    [[userInfo objectForKey:UIKeyboardAnimationCurveUserInfoKey] getValue:&animationCurve];
    [[userInfo objectForKey:UIKeyboardAnimationDurationUserInfoKey] getValue:&animationDuration];
    [[userInfo objectForKey:UIKeyboardFrameEndUserInfoKey] getValue:&keyboardEndFrame];

    [UIView beginAnimations:nil context:nil];
    [UIView setAnimationDuration:animationDuration];
    [UIView setAnimationCurve:animationCurve];
    self.textView.frame = self.view.frame;
    [UIView commitAnimations];  
}

该片段包含一些额外的内容,可以与键盘动画同步地设置过渡动画.

在我使用的这个片段中self.textView,您可能希望将其更改为self.scrollView.这段代码的优点在于它适用于所有方向和iPad.看看代码,希望它是自我解释的.