//将要显示键盘    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(willShowKeyboard:) name:UIKeyboardWillShowNotification object:nil];    //将要隐藏键盘    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(willHideKeyboard:) name:UIKeyboardWillHideNotification object:nil];    //显示键盘完成    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(DidShowKeyboard:) name:UIKeyboardDidShowNotification object:nil];    //隐藏键盘完成    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(DidHideKeyboard:) name:UIKeyboardDidHideNotification object:nil];    //键盘frame将要改变    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardDidChange:) name:UIKeyboardDidChangeFrameNotification object:nil];    //键盘frame将要改变    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillChange:) name:UIKeyboardWillChangeFrameNotification object:nil];