uiscrollview - MonoTouch：带有 InputView DatePicker 的 UITextField 被键盘横向隐藏

Question

我有一个 UITextField 我放在我的屏幕底部：

通常这个文本字段会被键盘隐藏，但我遵循了以下组合：

• http://spazzarama.com/2011/09/07/monotouch-auto-scroll-uitextfield-or-other-views-hidden-by-keyboard/
• http://www.ashokkarunakaran.com/2012/09/08/monotouchdatepicker/

并创建了我的 UITextField ，当它被选中时会显示一个日期选择器，并且 UITextField 会自动向上滚动：

这很好用，直到我将手机旋转到横向。

一旦在风景中，我的 UITextField 被推到屏幕上太远，不再看到它。

在代码中，我订阅了 UIKeyboard.WillShowNotification 并在下面调用 KeyboardWillShowNotification：

protected virtual void KeyboardWillShowNotification (NSNotification notification)
        {
            UIView activeView = KeyboardGetActiveView();
            if (activeView == null)
                return;

            UIScrollView scrollView = activeView.FindSuperviewOfType(this.View, typeof(UIScrollView)) as UIScrollView;
            if (scrollView == null)
                return;

            RectangleF keyboardBounds = UIKeyboard.FrameBeginFromNotification(notification);

            UIEdgeInsets contentInsets = new UIEdgeInsets(0.0f, 0.0f, keyboardBounds.Size.Height, 0.0f);
            scrollView.ContentInset = contentInsets;
            scrollView.ScrollIndicatorInsets = contentInsets;

            // If activeField is hidden by keyboard, scroll it so it's visible
            RectangleF viewRectAboveKeyboard = new RectangleF(this.View.Frame.Location, new SizeF(this.View.Frame.Width, this.View.Frame.Size.Height - keyboardBounds.Size.Height));

            RectangleF activeFieldAbsoluteFrame = activeView.Superview.ConvertRectToView(activeView.Frame, this.View);
            // activeFieldAbsoluteFrame is relative to this.View so does not include any scrollView.ContentOffset

            // Check if the activeField will be partially or entirely covered by the keyboard
            if (!viewRectAboveKeyboard.Contains(activeFieldAbsoluteFrame))
            {
                // Scroll to the activeField Y position + activeField.Height + current scrollView.ContentOffset.Y - the keyboard Height
                PointF scrollPoint = new PointF(0.0f, activeFieldAbsoluteFrame.Location.Y + activeFieldAbsoluteFrame.Height + scrollView.ContentOffset.Y - viewRectAboveKeyboard.Height);
                scrollView.SetContentOffset(scrollPoint, true);
            }
        }

两个补充功能：

protected virtual UIView KeyboardGetActiveView()
        {
            return this.View.FindFirstResponder();
        }

public static UIView FindFirstResponder (this UIView view)
    {
        if (view.IsFirstResponder)
        {
            return view;
        }
        foreach (UIView subView in view.Subviews) {
            var firstResponder = subView.FindFirstResponder();
            if (firstResponder != null)
                return firstResponder;
        }
        return null;
    }

    public static UIView FindSuperviewOfType(this UIView view, UIView stopAt, Type type)
    {
        if (view.Superview != null)
        {
            if (type.IsAssignableFrom(view.Superview.GetType()))
            {
                return view.Superview;
            }

            if (view.Superview != stopAt)
                return view.Superview.FindSuperviewOfType(stopAt, type);
        }

        return null;
    }

BitBucket 上有完整源代码：https ://bitbucket.org/benhysell/uitextfielddatepicker

关于我可能做错了什么的想法？

Answer 1

显示键盘时，您应该修改视图的高度。

像这样的东西：

var frame = View.Frame;
frame.Height -= keyboardHeight;
View.Frame = frame;

获取键盘高度：

bool isLandscape = InterfaceOrientation == UIInterfaceOrientation.LandscapeLeft || InterfaceOrientation == UIInterfaceOrientation.LandscapeRight;
var keyboardFrame = UIKeyboard.FrameEndFromNotification (notification);
var keyboardHeight = isLandscape ? keyboardFrame.Width : keyboardFrame.Height;

只要您UITextField的 'sAutoResizingMask设置为居中，那么您的 UI 应该看起来正确。