iphone - 从横向切换到纵向后，将 UIScrollView 保持在正确的位置

Question

我有一个包含文本字段和 TextView 的 UIScrollView。当键盘存在时，我有代码将文本字段向上移动，这样键盘就不会覆盖文本字段。此代码在纵向 View 中效果很好:

-(BOOL)textFieldShouldReturn:(UITextField *)textField {
    if(textField) {
        [textField resignFirstResponder];
    }
    return NO;
}

-(void)textFieldDidBeginEditing:(UITextField *)textField {
    if (textField == self.nameField) {
        [UIView beginAnimations:nil context:NULL];
        [UIView setAnimationDelegate:self];
        [UIView setAnimationDuration:0.3];
        [UIView setAnimationBeginsFromCurrentState:YES];
        self.view.frame = CGRectMake(self.view.frame.origin.x,   (self.view.frame.origin.y - 90), self.view.frame.size.width, self.view.frame.size.height);
        [UIView commitAnimations];
    }
}

-(void)textFieldDidEndEditing:(UITextField *)textField {
    if (textField == self.nameField) {
        [UIView beginAnimations:nil context:NULL];
        [UIView setAnimationDelegate:self];
        [UIView setAnimationDuration:0.3];
        [UIView setAnimationBeginsFromCurrentState:YES];
        self.view.frame = CGRectMake(self.view.frame.origin.x, (self.view.frame.origin.y + 90), self.view.frame.size.width, self.view.frame.size.height);
        [UIView commitAnimations];
    }
}

-(void)textViewDidBeginEditing:(UITextView *)textField {
    if (textField == self.questionField) {
        [UIView beginAnimations:nil context:NULL];
        [UIView setAnimationDelegate:self];
        [UIView setAnimationDuration:0.3];
        [UIView setAnimationBeginsFromCurrentState:YES];
        self.view.frame = CGRectMake(self.view.frame.origin.x, (self.view.frame.origin.y - 200), self.view.frame.size.width, self.view.frame.size.height);
        [UIView commitAnimations];
    }
}

-(void)textViewShouldEndEditing:(UITextView *)textField {
    if (textField == self.questionField) {
        [UIView beginAnimations:nil context:NULL];
        [UIView setAnimationDelegate:self];
        [UIView setAnimationDuration:0.3];
        [UIView setAnimationBeginsFromCurrentState:YES];
        UIInterfaceOrientation interfaceOrientation = self.interfaceOrientation;

        self.view.frame = CGRectMake(self.view.frame.origin.x, (self.view.frame.origin.y + 200), self.view.frame.size.width, self.view.frame.size.height);
        [UIView commitAnimations];
    }
}

当我将 iPhone 模拟器旋转到横向 View 时，这(不足为奇)不起作用。在横向和纵向 View 中输入文本时，如何让文本字段向上移动到足以看到它的程度？

此外，如果我在显示键盘时从横向旋转到纵向，则在关闭键盘后， ScrollView 已向下移动到屏幕，而不是在其原始位置排列。我怎样才能避免这种情况？

Answer 1

苹果文档Managing the Keyboard在“移动位于键盘下方的内容”标题下显示了执行此操作的正确方法。

您基本上是将内容放在 ScrollView 上，并使用 UIKeyboardDidShowNotification 和 UIKeyboardWillHideNotification 通知来调整内容偏移量。

但是，代码有些不完整。键盘尺寸计算在横向模式下不起作用。要修复它，请替换为:

CGSize kbSize = [[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size;

有了这个:

// Works in both portrait and landscape mode
CGRect kbRect = [[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue];
kbRect = [self.view convertRect:kbRect toView:nil];

CGSize kbSize = kbRect.size;