IOS官方的Object-C有例子，但是OC的代码。Moving Content That Is Located Under the Keyboard
效果如下图：
实现方法：
1.定义一个所有ViewControl的基类，命名为ViewControllerBase，ViewControl继承ViewControllerBase
代码如下：
class ViewControllerBase : UIViewController
2: {
3: NSObject _keyboardObserverWillShow;
4: NSObject _keyboardObserverWillHide;
5:
public ViewControllerBase()
7: {
8: }
base(handle)
10: {
11:
12: }
13:
void ViewDidLoad()
15: {
//设置键盘事件处理程序
17: RegisterForKeyboardNotifications();
18: }
19:
void RegisterForKeyboardNotifications()
21: {
22: _keyboardObserverWillShow = NSNotificationCenter.DefaultCenter.AddObserver
23: (UIKeyboard.WillShowNotification, KeyboardWillShowNotification);
24:
25: _keyboardObserverWillHide = NSNotificationCenter.DefaultCenter.AddObserver
26: (UIKeyboard.WillHideNotification, KeyboardWillHideNotification);
27: }
28:
void UnregisterKeyboardNotifications()
30: {
31: NSNotificationCenter.DefaultCenter.RemoveObserver(_keyboardObserverWillShow);
32: NSNotificationCenter.DefaultCenter.RemoveObserver(_keyboardObserverWillHide);
33: }
34:
virtual UIView KeyboardGetActiveView()
36: {
this.View.FindFirstResponder();
38: }
39:
void KeyboardWillShowNotification(NSNotification notification)
41: {
42: UIView activeView = KeyboardGetActiveView();
null)
return;
45:
as UIScrollView;
null)
return;
49:
50: RectangleF keyboardBounds = UIKeyboard.BoundsFromNotification(notification);
51:
new UIEdgeInsets(0.0f, 0.0f, keyboardBounds.Size.Height, 0.0f);
53: scrollView.ContentInset = contentInsets;
54: scrollView.ScrollIndicatorInsets = contentInsets;
55:
this.View.Frame.Location,
this.View.Frame.Size.Height - keyboardBounds.Size.Height));
58:
this.View);
60:
if (!viewRectAboveKeyboard.Contains(activeFieldAbsoluteFrame))
62: {
new PointF(0.0f,
64: activeFieldAbsoluteFrame.Location.Y + activeFieldAbsoluteFrame.Height
65: + scrollView.ContentOffset.Y - viewRectAboveKeyboard.Height);
true);
67: }
68: }
69:
void KeyboardWillHideNotification(NSNotification notification)
71: {
72: UIView activeView = KeyboardGetActiveView();
null)
return;
75:
as UIScrollView;
null)
return;
79:
double animationDuration = UIKeyboard.AnimationDurationFromNotification(notification);
new UIEdgeInsets(0.0f, 0.0f, 0.0f, 0.0f);
delegate
83: {
84: scrollView.ContentInset = contentInsets;
85: scrollView.ScrollIndicatorInsets = contentInsets;
86: });
87: }
88: }