IOS 监听键盘的通知（NSNotificationCenter）

/**
*  当键盘改变了frame(位置和尺寸)的时候调用
*/
- (void)keyboardWillChangeFrame:(NSNotification *)note
{
// 设置窗口的颜色
self.view.window.backgroundColor = self.tableView.backgroundColor;

// 0.取出键盘动画的时间
CGFloat duration = [note.userInfo[UIKeyboardAnimationDurationUserInfoKey] doubleValue];

// 1.取得键盘最后的frame
CGRect keyboardFrame = [note.userInfo[UIKeyboardFrameEndUserInfoKey] CGRectValue];

// 2.计算控制器的view需要平移的距离
CGFloat transformY = keyboardFrame.origin.y - self.view.frame.size.height;

// 3.执行动画
[UIView animateWithDuration:duration animations:^{
self.view.transform = CGAffineTransformMakeTranslation(0, transformY);
}];
}

/*
UIKeyboardAnimationCurveUserInfoKey = 7;  // 动画的执行节奏(速度)
UIKeyboardAnimationDurationUserInfoKey = "0.25"; // 键盘弹出\隐藏动画所需要的时间
UIKeyboardBoundsUserInfoKey = "NSRect: {{0, 0}, {320, 216}}";
UIKeyboardCenterBeginUserInfoKey = "NSPoint: {160, 588}";
UIKeyboardCenterEndUserInfoKey = "NSPoint: {160, 372}";
UIKeyboardFrameChangedByUserInteraction = 0;

// 键盘弹出
UIKeyboardFrameBeginUserInfoKey = "NSRect: {{0, 480}, {320, 216}}";// 键盘刚出来那一刻的frame
UIKeyboardFrameEndUserInfoKey = "NSRect: {{0, 264}, {320, 216}}"; //  键盘显示完毕后的frame

// 键盘隐藏
UIKeyboardFrameBeginUserInfoKey = "NSRect: {{0, 264}, {320, 216}}";
UIKeyboardFrameEndUserInfoKey = "NSRect: {{0, 480}, {320, 216}}";
*/

// 2.监听键盘的通知
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillChangeFrame:) name:UIKeyboardWillChangeFrameNotification object:nil];

-(void)dealloc
{

//[super dealloc]; 非ARC的情况需要这一步
[[NSNotificationCenter defaultCenter]removeObserver:self];
}