Question

我在vc中有一个表单。在表单中有一些字段和文本视图。当用户单击文本区键盘弹出时，用户开始在其上键入。但问题是文本视图隐藏在键盘后面，用户无法看到他/她正在写什么。有没有办法让用户无法解决这个问题？屏幕看起来像这样

Answer 1

我建议您在键盘消失时键盘显示和向下移动视图。如果你想这样做：

如果您现在拥有的内容不适合iPhone屏幕，则只需要ScrollView。（如果要将ScrollView添加为组件的超级视图。只需在键盘出现时使TextField向上滚动，则不需要它。）为了显示文本字段而不被键盘隐藏，标准方法是在显示键盘时向上/向下移动具有文本字段的视图。以下是一些示例代码：

#define kOFFSET_FOR_KEYBOARD 80.0

-(void)keyboardWillShow {
    // Animate the current view out of the way
    if (self.view.frame.origin.y >= 0)
    {
        [self setViewMovedUp:YES];
    }
    else if (self.view.frame.origin.y < 0)
    {
        [self setViewMovedUp:NO];
    }
}

-(void)keyboardWillHide {
    if (self.view.frame.origin.y >= 0)
    {
        [self setViewMovedUp:YES];
    }
    else if (self.view.frame.origin.y < 0)
    {
        [self setViewMovedUp:NO];
    }
}

-(void)textFieldDidBeginEditing:(UITextField *)sender
{
    if ([sender isEqual:mailTf])
    {
        //move the main view, so that the keyboard does not hide it.
        if  (self.view.frame.origin.y >= 0)
        {
            [self setViewMovedUp:YES];
        }
    }
}

//method to move the view up/down whenever the keyboard is shown/dismissed
-(void)setViewMovedUp:(BOOL)movedUp
{
    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationDuration:0.3]; // if you want to slide up the view

    CGRect rect = self.view.frame;
    if (movedUp)
    {
        // 1. move the view's origin up so that the text field that will be hidden come above the keyboard 
        // 2. increase the size of the view so that the area behind the keyboard is covered up.
        rect.origin.y -= kOFFSET_FOR_KEYBOARD;
        rect.size.height += kOFFSET_FOR_KEYBOARD;
    }
    else
    {
        // revert back to the normal state.
        rect.origin.y += kOFFSET_FOR_KEYBOARD;
        rect.size.height -= kOFFSET_FOR_KEYBOARD;
    }
    self.view.frame = rect;

    [UIView commitAnimations];
}


- (void)viewWillAppear:(BOOL)animated
{
    [super viewWillAppear:animated];
    // register for keyboard notifications
    [[NSNotificationCenter defaultCenter] addObserver:self
                                         selector:@selector(keyboardWillShow)
                                             name:UIKeyboardWillShowNotification
                                           object:nil];

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

- (void)viewWillDisappear:(BOOL)animated
{
    [super viewWillDisappear:animated];
    // unregister for keyboard notifications while not visible.
    [[NSNotificationCenter defaultCenter] removeObserver:self
                                             name:UIKeyboardWillShowNotification
                                           object:nil];

    [[NSNotificationCenter defaultCenter] removeObserver:self
                                             name:UIKeyboardWillHideNotification
                                           object:nil];
}

Answer 2

将表单放入自己的视图中，然后在键盘出现/消失时调整View的底部约束。

要启用键盘出现的通知，请将以下行添加到viewDidLoad：

NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow(notification:)), name: NSNotification.Name.UIKeyboardWillShow, object: nil)

实现keyboardWillShow以在键盘视图出现时将约束提升：

func keyboardWillShow(notification: NSNotification) {
    if let info = notification.userInfo {
        let rect: CGRect = info["UIKeyboardFrameEndUserInfoKey"] as! CGRect //get the keyboard frame as CGRect to get its dimensions
        self.view.layoutIfNeeded()

        UIView.animate(withDuration: 0.25, animations: {
            self.formViewBottomConstraint?.constant = rect.height + 14 //replace 14 with your desired pixel offset from the top of the keyboard
            self.view.layoutIfNeeded()
        })
    }
}

最后，当键盘消失后，将视图的底部约束重置为原始值：

func textFieldShouldReturn(_ textField: UITextField) -> Bool {
        textField.resignFirstResponder()
        self.formViewBottomConstraint?.constant = 14
        return true
}

上面的代码只是将整个视图滑动到键盘上方，但是如果要上下滑动视图以使每个文本字段位于键盘正上方（并且针对每个文本字段进行调整），则只需设置键盘出现时相对于textField的frame.origin.y的底部约束。

调整键盘以在IOS中显示其背后的内容

2 个答案: