[iOS]如何動態獲取鍵盤的高度

// 給鍵盤添加監聽事件

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(myKeyBoardAction:) name:UIKeyboardDidShowNotification object:nil];

NSDictionary *dic = [notif userInfo];

    NSValue *value = [dic objectForKey:UIKeyboardFrameBeginUserInfoKey];

    CGSize size = [value CGRectValue].size;