Iphone Autoscroll UIScrollView以适应本机iOS Mail.app中的内容

原生iOS

Mail.app

在创建新信件时具有强大的功能。整个屏幕是一个

UIScrollView

，而书写信件正文的位置是一个

UITextView

，滚动被禁用

键入此

TextView

的高度以及

UIScrollView

的高度会动态更改，并且

UIScrollView

会向下滚动，在键盘上方留下一些像素以显示新文本

我知道这一过程必须在

textViewDidChange

方法中完成，但在尝试这样做的同时，我的代码中出现了一些错误-

UITextField

有时可能会在

UIScrollView

下关闭。以下是我如何尝试做到这一点：

-(void)textViewDidChange:(UITextView *)textView {

    CGRect frame = emailTextView.frame;
    frame.size.height = emailTextView.contentSize.height;
    emailTextView.frame = frame;
    mainScrollView.contentSize = CGSizeMake(320, emailTextView.contentSize.height + rightKeyboardSize.height + 20);

}

---

你知道这里出了什么问题吗？提前谢谢

好的，我实施了自己的示例项目来找到答案。你应该替换你的名字

首先，我将添加观察者来检测键盘何时显示或隐藏：

- (void)addKeyboardObserver
{
    // This could be in an init method.
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardDidShow:) name:UIKeyboardDidShowNotification object:nil];

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

- (void)keyboardDidShow:(NSNotification*)notification
{
    NSDictionary* keyboardInfo = [notification userInfo];
    NSValue* keyboardFrameBegin = [keyboardInfo valueForKey:UIKeyboardFrameBeginUserInfoKey];
    _keyboardFrameBeginRect = [keyboardFrameBegin CGRectValue];
    UIScrollView *_scrollView = (UIScrollView*)self.view;
    _scrollView.frame = CGRectMake(_scrollView.frame.origin.x,
                                   _scrollView.frame.origin.y,
                                   _scrollView.frame.size.width,
                                   _scrollView.frame.size.height - _keyboardFrameBeginRect.size.height);
}

- (void)keyboardDidHide:(NSNotification*)notification
{
    UIScrollView *_scrollView = (UIScrollView*)self.view;
    _scrollView.frame = CGRectMake(_scrollView.frame.origin.x,
                                   _scrollView.frame.origin.y,
                                   _scrollView.frame.size.width,
                                   _scrollView.frame.size.height +
                               _keyboardFrameBeginRect.size.height);
}

然后，textViewDidChange:方法更改为：

- (void)textViewDidChange:(UITextView *)textView
{
    UIScrollView *_scrollView = (UIScrollView*)self.view;
    _textView.frame = CGRectMake(_textView.frame.origin.x,
                                 _textView.frame.origin.y,
                                 _textView.contentSize.width,
                                 _textView.contentSize.height);
    _scrollView.contentSize = _textView.frame.size;

    if (_scrollView.frame.size.height < _textView.frame.size.height) {
        CGPoint bottomOffset = CGPointMake(0,_textView.frame.size.height-_keyboardFrameBeginRect.size.height);
        [_scrollView setContentOffset:bottomOffset animated:NO];
    }
}

-（无效）textViewDidChange:（UITextView*）textView
{
UIScrollView*_scrollView=（UIScrollView*）self.view；
_textView.frame=CGRectMake（_textView.frame.origin.x，
_textView.frame.origin.y，
_textView.contentSize.width，
_textView.contentSize.height）；
_scrollView.contentSize=\u textView.frame.size；
如果（_scrollView.frame.size.height<_textView.frame.size.height）{
CGPoint bottomOffset=CGPointMake（0，_textView.frame.size.height-_keyboardFrameBeginRect.size.height）；
[_ScrollViewSetContentOffset:bottomOffset动画：否]；
}
}

---

祝你好运

好的，我实施了自己的示例项目来找到答案。你应该替换你的名字

首先，我将添加观察者来检测键盘何时显示或隐藏：

- (void)addKeyboardObserver
{
    // This could be in an init method.
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardDidShow:) name:UIKeyboardDidShowNotification object:nil];

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

- (void)keyboardDidShow:(NSNotification*)notification
{
    NSDictionary* keyboardInfo = [notification userInfo];
    NSValue* keyboardFrameBegin = [keyboardInfo valueForKey:UIKeyboardFrameBeginUserInfoKey];
    _keyboardFrameBeginRect = [keyboardFrameBegin CGRectValue];
    UIScrollView *_scrollView = (UIScrollView*)self.view;
    _scrollView.frame = CGRectMake(_scrollView.frame.origin.x,
                                   _scrollView.frame.origin.y,
                                   _scrollView.frame.size.width,
                                   _scrollView.frame.size.height - _keyboardFrameBeginRect.size.height);
}

- (void)keyboardDidHide:(NSNotification*)notification
{
    UIScrollView *_scrollView = (UIScrollView*)self.view;
    _scrollView.frame = CGRectMake(_scrollView.frame.origin.x,
                                   _scrollView.frame.origin.y,
                                   _scrollView.frame.size.width,
                                   _scrollView.frame.size.height +
                               _keyboardFrameBeginRect.size.height);
}

然后，textViewDidChange:方法更改为：

- (void)textViewDidChange:(UITextView *)textView
{
    UIScrollView *_scrollView = (UIScrollView*)self.view;
    _textView.frame = CGRectMake(_textView.frame.origin.x,
                                 _textView.frame.origin.y,
                                 _textView.contentSize.width,
                                 _textView.contentSize.height);
    _scrollView.contentSize = _textView.frame.size;

    if (_scrollView.frame.size.height < _textView.frame.size.height) {
        CGPoint bottomOffset = CGPointMake(0,_textView.frame.size.height-_keyboardFrameBeginRect.size.height);
        [_scrollView setContentOffset:bottomOffset animated:NO];
    }
}

-（无效）textViewDidChange:（UITextView*）textView
{
UIScrollView*_scrollView=（UIScrollView*）self.view；
_textView.frame=CGRectMake（_textView.frame.origin.x，
_textView.frame.origin.y，
_textView.contentSize.width，
_textView.contentSize.height）；
_scrollView.contentSize=\u textView.frame.size；
如果（_scrollView.frame.size.height<_textView.frame.size.height）{
CGPoint bottomOffset=CGPointMake（0，_textView.frame.size.height-_keyboardFrameBeginRect.size.height）；
[_ScrollViewSetContentOffset:bottomOffset动画：否]；
}
}

---

祝你好运

您的方法仅在UITextView可滚动时有效，而在禁用其滚动时无效。另外，我还有一个需要滚动的UIScrollView。UIScrollView有屏幕的大小？不，它的大小取决于UINavigationBar，并且是可自定义的，非常感谢！我一定会尝试一下，并报告结果！我在您的方法中上载示例项目，仅当UITextView可滚动时有效，而不是当其滚动被禁用时有效。另外，我还有一个需要滚动的UIScrollView。UIScrollView有屏幕的大小？不，它的大小取决于UINavigationBar，并且是可自定义的，非常感谢！我一定会尝试一下，并报告结果！我将示例项目上传到