iOS键盘监听处理遮挡控件问题(整理)

#pragma mark - 键盘处理
#pragma mark 监听系统发出的键盘通知
- (void)addKeyboardNote
{
    NSNotificationCenter *center = [NSNotificationCenter defaultCenter];
    
    // 1.显示键盘
    [center addObserver:self selector:@selector(keyboardWillShow:) name:UIKeyboardWillShowNotification object:nil];
    
    // 2.隐藏键盘
    [center addObserver:self selector:@selector(keyboardWillHide:) name:UIKeyboardWillHideNotification object:nil];
}

• 显示方法

#pragma mark 显示一个新的键盘就会调用
- (void)keyboardWillShow:(NSNotification *)note
{
    // 1.取得当前聚焦文本框最下面的Y值
    CGFloat loginBtnMaxY = CGRectGetMaxY(loginBtn.frame);
    // 2.取出键盘的高度
    CGFloat keyboardH = [note.userInfo [UIKeyboardFrameEndUserInfoKey] CGRectValue].size.height;
    // 3.控制器view的高度 - 键盘的高度
    CGFloat keyboardY = self.view.frame.size.height - keyboardH;
    // 4.比较登录按钮最大Y 跟 键盘Y
    CGFloat duration = [note.userInfo [UIKeyboardAnimationDurationUserInfoKey] doubleValue];

    if (duration <= 0.0) {
        duration = 0.25;
    }
    
    [UIView animateWithDuration:duration animations:^{
        if (loginBtnMaxY > keyboardY) { // 键盘挡住了登录按钮
            self.view.transform = CGAffineTransformMakeTranslation(0, keyboardY - loginBtnMaxY - 8);
        } else { // 没有挡住登录按钮
            self.view.transform = CGAffineTransformIdentity;
        }
    }];
}

• 隐藏方法

#pragma mark 隐藏键盘就会调用
- (void)keyboardWillHide:(NSNotification *)note
{
    CGFloat duration = [note.userInfo [UIKeyboardAnimationDurationUserInfoKey] doubleValue];
    [UIView animateWithDuration:duration animations:^{
        self.view.transform = CGAffineTransformIdentity;
    }];
}

• 销毁处理

- (void)dealloc
{
    [[NSNotificationCenter defaultCenter] removeObserver:self];
}