IOS 判断键盘的弹出与关闭状态

1，首先定义一个属性@property(assign,nonatomic) BOOL isVisable;

2,在-(void)viewWillAppear 中添加对键盘的监听

    NSNotificationCenter *center = [NSNotificationCenter defaultCenter];

    [center addObserver:selfselector:@selector(keyboardDidShow)name:UIKeyboardDidShowNotificationobject:nil];

    [center addObserver:selfselector:@selector(keyboardDidHide)name:UIKeyboardWillHideNotificationobject:nil];

3，-(void)keyboardDidShow{

self.isVisable = YES;

}

-(void)keyboardDidHide{

self.isVisable = NO;

}

4,在-(void)viewWillDisappear 中

    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardDidShowNotification object:nil];

    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardDidHideNotification object:nil];