完美解决ios4与ios5输入框随键盘移动问题

      iOS5中当键盘输入法切换到中文时，键盘高度由216增加到252像素。这一变化将遮住输入框。如何才能解决这一问题呢？

      在iOS5中，新增有notification（UIKeyboardWillChangeFrameNotification）可以用来监测键盘frame的变化。在iOS4中，可以通过UIKeyboardWillShowNotification以及UIKeyboardWillHideNotification来监测键盘的显示与隐藏事件。综合处理下，可以用以下方法解决：

 #ifndef IOS_VERSION
 #define IOS_VERSION [[[UIDevice currentDevice] systemVersion] floatValue]
 #endif

在viewdidload中注册监测事件：

 if (IOS_VERSION < 5.0) {
     [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillChangeFrame:) name:UIKeyboardWillShowNotification object:nil];
     [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillChangeFrame:) name:UIKeyboardWillHideNotification object:nil];
 }else{
     [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillChangeFrame:) name:UIKeyboardWillChangeFrameNotification object:nil];
 }

在dealloc中移除监测事件：

 if (IOS_VERSION < 5.0) {
     [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillShowNotification object:nil];
     [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillHideNotification object:nil];
 }else{
     [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillChangeFrameNotification object:nil];
 }

事件处理函数：

 - (void)keyboardWillChangeFrame:(NSNotification *)notification{
     if(!isDisplayFaceBox){
 #if __IPHONE_OS_VERSION_MAX_ALLOWED >= __IPHONE_3_2
         if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPhone) {
 #endif
 #if __IPHONE_OS_VERSION_MIN_REQUIRED >= __IPHONE_3_2
             NSValue *keyboardBoundsValue = [[notification userInfo] objectForKey:UIKeyboardFrameEndUserInfoKey];
 #else
             NSValue *keyboardBoundsValue = [[notification userInfo] objectForKey:UIKeyboardBoundsUserInfoKey];
 #endif
             CGRect keyboardBounds;
             [keyboardBoundsValue getValue:&keyboardBounds];
             //UIEdgeInsets e = UIEdgeInsetsMake(0, 0, keyboardBounds.size.height, 0);
             //[keyboardScrollView setScrollIndicatorInsets:e];
             //[keyboardScrollView setContentInset:e];

             NSInteger offset = 480-keyboardBounds.origin.y;
             CGRect listFrame = CGRectMake(0, offset, 320, 377-offset);

             [UIView beginAnimations:@"anim" context:NULL];
             [UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];
             [UIView setAnimationBeginsFromCurrentState:YES];
             [UIView setAnimationDuration:0.3];
             //处理移动事件，将各视图设置最终要达到的状态
             [tableviewbo setFrame:listFrame];

             faceButton.hidden = NO;
             keyboardButton.hidden = YES;

             [keyboardScrollView setContentOffset:CGPointMake(0, offset) animated:NO];

             [self scrollToBottomAnimated:NO];

             [UIView commitAnimations];

 #if __IPHONE_OS_VERSION_MAX_ALLOWED >= __IPHONE_3_2
         }
 #endif
     }
 }