如何使UITextView在键盘可见时一直滚动到底部

本文对此进行了广泛讨论: How to make a UITextField move up when keyboard is present?

我个人过去用过Shiun的解决方案,效果很好。

更新: 如果不想使用该方法,一个稍微简单的方法是在键盘显示时调整文本字段的大小。最好按照我在上面发布的链接上的说明操作,因为键盘将显示通知,让您可以访问键盘高度。

首先设置UITextField=self的委托。然后:

-(void)textFieldDidBeginEditing:(UITextField *)textField { // This is where the keyboard becomes visible
    textField.frame = CGRectMake(textField.frame.origin.x, textField.frame.origin.y, textField.frame.size.width, textField.frame.size.height-100);
}

-(void)textFieldDidEndEditing:(UITextField *)textField { // This is where the keyboard hides itself
    textField.frame = CGRectMake(textField.frame.origin.x, textField.frame.origin.y, textField.frame.size.width, textField.frame.size.height+100);
}

你可以根据你的方向等调整100。如果你想添加一些动画,你可以:

-(void)textFieldDidBeginEditing:(UITextField *)textField { // This is where the keyboard becomes visible
        [UIView beginAnimations:nil context:NULL];
        [UIView setAnimationDelegate:self];
        [UIView setAnimationDuration:0.5];
        [UIView setAnimationBeginsFromCurrentState:YES];
        textField.frame = CGRectMake(textField.frame.origin.x, textField.frame.origin.y, textField.frame.size.width, textField.frame.size.height-100);
        [UIView commitAnimations];
    }

    -(void)textFieldDidEndEditing:(UITextField *)textField { // This is where the keyboard hides itself 
        [UIView beginAnimations:nil context:NULL];
        [UIView setAnimationDelegate:self];
        [UIView setAnimationDuration:0.5];
        [UIView setAnimationBeginsFromCurrentState:YES];
        textField.frame = CGRectMake(textField.frame.origin.x, textField.frame.origin.y, textField.frame.size.width, textField.frame.size.height+100);
        [UIView commitAnimations];
    }

编辑开始时,这将很好地将UITextView滚动到键盘顶部。如果您的UITextView具有动态高度(键入时自动显示/自动调整大小),这也将起作用。在iOS7中测试。

调用键盘观察者方法并将UITextView委托设置为当前类:

- (void)viewDidLoad
{
    ...
    [self observeKeyboard];
    textView.delegate = (id)self;
}

为UIKeyboardDidShowNotification和UIKeyboardWillShowNotification添加键盘观察者:

- (void)observeKeyboard
{
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillShow:) name:UIKeyboardWillShowNotification object:nil];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardDidShow:) name:UIKeyboardDidShowNotification object:nil];
}

获取键盘大小:

- (void)keyboardWillShow:(NSNotification *)notification
{
    CGSize keyboardSize = [[[notification userInfo] objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size;
    _keyboardHeight = keyboardSize.height;
} 

- (void)keyboardDidShow:(NSNotification *)notification
{
    CGSize keyboardSize = [[[notification userInfo] objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size;
    _keyboardHeight = keyboardSize.height;
}

当UITextView开始编辑或值已更改时调用 scrollKeyboardToTextView :

- (void)textViewDidBeginEditing:(UITextView *)textView
{
    [self scrollKeyboardToTextView:textView];
}

- (void)textViewDidChange:(UITextView *)textView
{
    [self scrollKeyboardToTextView:textView];
}

将带动画的UITextView滚动到键盘顶部:

- (void)scrollKeyboardToTextView:(UITextView *)textView
{
    UIEdgeInsets contentInsets = UIEdgeInsetsMake(0.0, 0.0, _keyboardHeight, 0.0);
    self.scrollView.contentInset = contentInsets;
    self.scrollView.scrollIndicatorInsets = contentInsets;

    CGRect aRect = self.view.frame;
    aRect.size.height -= _keyboardHeight;
    CGPoint origin = textView.frame.origin;
    origin.y -= self.scrollView.contentOffset.y;
    origin.y += textView.frame.size.height;

    CGPoint scrollPoint = CGPointMake(0.0, textView.frame.origin.y + textView.frame.size.height - (aRect.size.height));
    [self.scrollView setContentOffset:scrollPoint animated:YES];
}