我有一个包含 UITextView 的 UIViewCONtroller。当键盘出现时，我会像这样调整它的大小:

#pragma mark - Responding to keyboard events

- (void)keyboardDidShow:(NSNotification *)notification
{
    NSDictionary* info = [notification userInfo];
    CGRect keyboardSize = [[info objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue];
    CGRect newTextViewFrame = self.textView.frame;
    newTextViewFrame.size.height -= keyboardSize.size.height + 70;
    self.textView.frame = newTextViewFrame;
    self.textView.backgroundColor = [UIColor yellowColor];
}

- (void)keyboardWillHide:(NSNotification *)notification
{
    NSDictionary* info = [notification userInfo];
    CGRect keyboardSize = [[info objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue];
    CGRect newTextViewFrame = self.textView.frame;
    newTextViewFrame.size.height += keyboardSize.size.height - 70;
    self.textView.frame = newTextViewFrame;
}

textView 似乎重新调整到合适的大小，但是当用户键入时，光标最终会“超出”textView 框架。见下图:

黄色区域是UITextView框(不知道R键旁边的蓝线是什么)。我觉得这很有线。如果有任何区别，我正在使用 iOS7。

有什么想法或提示吗？

更新

我有一个 UITextView 子类，它使用以下方法绘制水平线(如果有任何不同):

- (void)drawRect:(CGRect)rect {

    //Get the current drawing context
    CGContextRef context = UIGraphicsGetCurrentContext();
    //Set the line color and width
    CGContextSetStrokeColorWithColor(context, [UIColor colorWithRed:229.0/255.0 green:244.0/255.0 blue:255.0/255.0 alpha:1].CGColor);
    CGContextSetLineWidth(context, 1.0f);
    //Start a new Path
    CGContextBeginPath(context);

    //Find the number of lines in our textView + add a bit more height to draw lines in the empty part of the view
    NSUInteger numberOfLines = (self.contentSize.height + rect.size.height) / self.font.lineHeight;

    CGFloat baselineOffset = 6.0f;

    //iterate over numberOfLines and draw each line
    for (int x = 0; x < numberOfLines; x++) {
        //0.5f offset lines up line with pixel boundary
        CGContextMoveToPoint(context, rect.origin.x, self.font.lineHeight*x + 0.5f + baselineOffset);
        CGContextAddLineToPoint(context, rect.size.width, self.font.lineHeight*x + 0.5f + baselineOffset);
    }

    // Close our Path and Stroke (draw) it
    CGContextClosePath(context);
    CGContextStrokePath(context);
}

最佳答案

为什么不调整框架的大小，为什么不给 TextView 一个 contentInset(和一个匹配的 scrollIndicatorInsets)？请记住， TextView 实际上是 ScrollView 。这是处理键盘(或其他)干扰的正确方法。

有关 contentInset 的更多信息，请参阅 this问题。

这似乎还不够。仍然使用 insets，因为这更正确(尤其是在 iOS7 上，键盘是透明的)，但您还需要对插入符号进行额外处理:

- (void)viewDidLoad
{
    [super viewDidLoad];

    [self.textView setDelegate:self];
    self.textView.keyboardDismissMode = UIScrollViewKeyboardDismissModeInteractive;

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

- (void)_keyboardWillShowNotification:(NSNotification*)notification
{
    UIEdgeInsets insets = self.textView.contentInset;
    insets.bottom += [notification.userInfo[UIKeyboardFrameEndUserInfoKey] CGRectValue].size.height;
    self.textView.contentInset = insets;

    insets = self.textView.scrollIndicatorInsets;
    insets.bottom += [notification.userInfo[UIKeyboardFrameEndUserInfoKey] CGRectValue].size.height;
    self.textView.scrollIndicatorInsets = insets;
}

- (void)_keyboardWillHideNotification:(NSNotification*)notification
{
    UIEdgeInsets insets = self.textView.contentInset;
    insets.bottom -= [notification.userInfo[UIKeyboardFrameBeginUserInfoKey] CGRectValue].size.height;
    self.textView.contentInset = insets;

    insets = self.textView.scrollIndicatorInsets;
    insets.bottom -= [notification.userInfo[UIKeyboardFrameBeginUserInfoKey] CGRectValue].size.height;
    self.textView.scrollIndicatorInsets = insets;
}

- (void)textViewDidBeginEditing:(UITextView *)textView
{
    _oldRect = [self.textView caretRectForPosition:self.textView.selectedTextRange.end];

    _caretVisibilityTimer = [NSTimer scheduledTimerWithTimeInterval:0.3 target:self selector:@selector(_scrollCaretToVisible) userInfo:nil repeats:YES];
}

- (void)textViewDidEndEditing:(UITextView *)textView
{
    [_caretVisibilityTimer invalidate];
    _caretVisibilityTimer = nil;
}

- (void)_scrollCaretToVisible
{
    //This is where the cursor is at.
    CGRect caretRect = [self.textView caretRectForPosition:self.textView.selectedTextRange.end];

    if(CGRectEqualToRect(caretRect, _oldRect))
        return;

    _oldRect = caretRect;

    //This is the visible rect of the textview.
    CGRect visibleRect = self.textView.bounds;
    visibleRect.size.height -= (self.textView.contentInset.top + self.textView.contentInset.bottom);
    visibleRect.origin.y = self.textView.contentOffset.y;

    //We will scroll only if the caret falls outside of the visible rect.
    if(!CGRectContainsRect(visibleRect, caretRect))
    {
        CGPoint newOffset = self.textView.contentOffset;

        newOffset.y = MAX((caretRect.origin.y + caretRect.size.height) - visibleRect.size.height + 5, 0);

        [self.textView setContentOffset:newOffset animated:YES];
    }
}

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

很多工作，Apple 应该提供更好的方式来处理插入符，但这行得通。

关于ios - 更改框架时 UITextView 光标位于框架下方，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/18431684/