iphone - 事件文本字段上的键盘滚动 - 滚动到 View 之外？

Question

我有一个应用程序，其 View 具有从 View 顶部到 View 底部的文本字段。我需要它在编辑底部字段时滚动以便字段可见，但它似乎无法正常工作。

在 Apple docs 之后，我将所有这些代码放入我的程序中( list 4-1、4-2)，并将 scrollView 和 activeField 导出添加到我的头文件并将它们链接到IB。

问题是，只要我点击一个文本字段，所有文本字段就会消失，直到我关闭键盘。他们向下滚动很远(再次，足够远到没有字段可见的地方)。

有谁知道这个问题可能是由什么引起的？

我将 Apple Docs 中的代码放在这里，这样您就可以准确地看到我正在使用的代码，而无需点击离开。

//my .h
    IBOutlet UIScrollView *scrollView;
    IBOutlet UITextField *activeField;

//.m
    // Call this method somewhere in your view controller setup code.
    - (void)registerForKeyboardNotifications
    {
        [[NSNotificationCenter defaultCenter] addObserver:self
                selector:@selector(keyboardWasShown:)
                name:UIKeyboardDidShowNotification object:nil];

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

}

// Called when the UIKeyboardDidShowNotification is sent.
- (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);
    scrollView.contentInset = contentInsets;
    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, activeField.frame.origin) ) {
        CGPoint scrollPoint = CGPointMake(0.0, activeField.frame.origin.y-kbSize.height);
        [scrollView setContentOffset:scrollPoint animated:YES];
    }
}

// Called when the UIKeyboardWillHideNotification is sent
- (void)keyboardWillBeHidden:(NSNotification*)aNotification
{
    UIEdgeInsets contentInsets = UIEdgeInsetsZero;
    scrollView.contentInset = contentInsets;
    scrollView.scrollIndicatorInsets = contentInsets;
}
- (void)textFieldDidBeginEditing:(UITextField *)textField
{
    activeField = textField;
}

- (void)textFieldDidEndEditing:(UITextField *)textField
{
    activeField = nil;
}

Answer 1

更新:以下答案已过时。现在您可以使用“TPkeyboardavoiding”库来处理 UIScrollView、UITableView 等中的所有类型的文本字段操作。尝试一下，如果有人在集成方面遇到问题，请告诉我。

旧答案

此功能无需注册键盘通知。为了使事件文本字段在键盘上方的屏幕居中，您只需设置 UIscrollView 的 contentOffset 两个方法，如下所示:

// called when textField start editting.
- (void)textFieldDidBeginEditing:(UITextField *)textField
{
    activeField = textField;
    [scrollView setContentOffset:CGPointMake(0,textField.center.y-60) animated:YES];
}



// called when click on the retun button.
- (BOOL)textFieldShouldReturn:(UITextField *)textField
{


    NSInteger nextTag = textField.tag + 1;
    // Try to find next responder
    UIResponder *nextResponder = [textField.superview viewWithTag:nextTag];

    if (nextResponder) {
        [scrollview setContentOffset:CGPointMake(0,textField.center.y-60) animated:YES];
        // Found next responder, so set it.
        [nextResponder becomeFirstResponder];
    } else {
        [scrollview setContentOffset:CGPointMake(0,0) animated:YES];
        [textField resignFirstResponder];   
        return YES;
    }

    return NO; 
}

注意:所有 TextField 都应该有增量标签，比如 1、2、3 等等。并将委托(delegate)设置为 self 。

谢谢，