iOS開發 - 通知傳值（2020）

通知的使用

• 通知傳值
• 通知監聽

1.通知傳值 （

UIViewController

）

NSDictionary *dict = @{@"c2cmsg":self.codeMessageValue};
[[NSNotificationCenter defaultCenter] postNotificationName:@"c2cSellout" object:nil userInfo:dict];
           

我碰到的情況：在

scrollview

上滑動建立兩個類似自定義

UIView

導緻通知重複建立，然後最終導緻通知的方法被多次調用

• 首先在重新整理自定義UIView的時候先移除一次通知(

  CustomView

  )

/** 移除特定通知-再建立不然就會重複 */
 [[NSNotificationCenter defaultCenter] removeObserver:self name:@"c2cSellout" object:nil];
 [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(sellc2cout:) name:@"c2cSellout" object:nil];
           

#pragma mark - 監聽
- (void)sellc2cout:(NSNotification *)notification{
    /** 移除特定通知-再建立不然就會重複 */
[[NSNotificationCenter defaultCenter] removeObserver:self name:@"c2cSellout" object:nil];
[self loadPublishOrderWithType:MYDC2CTransCenterViewTypeForSell valicode:notification.userInfo[@"c2cmsg"]];
}
           

• 移除通知（UIViewcontroller CustomView）

/** 移除通知 */
- (void)dealloc
{
    [[NSNotificationCenter defaultCenter] removeObserver:self];
}
           

2.通知監聽

/** 注冊監聽通知-鍵盤回收和展開 */
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillChangeFrame:) name:UIKeyboardWillShowNotification object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardDidHide:) name:UIKeyboardWillHideNotification object:nil];


           

• 監聽鍵盤彈出

- (void)keyboardWillChangeFrame:(NSNotification *)notification{
    //取出鍵盤動畫的時間(根據userInfo的key----UIKeyboardAnimationDurationUserInfoKey)
    CGFloat duration = [notification.userInfo[UIKeyboardAnimationDurationUserInfoKey] floatValue];
    
    //取得鍵盤最後的frame(根據userInfo的key----UIKeyboardFrameEndUserInfoKey = "NSRect: {{0, 227}, {320, 253}}";)
    CGRect keyboardFrame = [notification.userInfo[UIKeyboardFrameEndUserInfoKey] CGRectValue];
    
    //計算控制器的view需要平移的距離
    CGFloat transformY = keyboardFrame.origin.y - self.view.frame.size.height;
    
    //執行動畫
    [UIView animateWithDuration:duration animations:^{
        [self.codeContentView mas_remakeConstraints:^(MASConstraintMaker *make) {
            make.left.right.equalTo(self.codeBgView);
            make.height.equalTo(@(SCREEN_HEIGHT*0.4));
            make.bottom.equalTo(self.codeBgView.mas_bottom).offset(transformY-90);
        }];
    }];
}
           

• 監聽鍵盤收回

- (void)keyboardDidHide:(NSNotification *)notification{
    CGFloat duration = [notification.userInfo[UIKeyboardAnimationDurationUserInfoKey] floatValue];
    [UIView animateWithDuration:duration animations:^{
        [self.codeContentView mas_remakeConstraints:^(MASConstraintMaker *make) {
            make.left.right.bottom.equalTo(self.codeBgView);
            make.height.equalTo(@(SCREEN_HEIGHT*0.4));
            
        }];
    }];
}

           

• 最後移除通知

/** 移除通知 */
- (void)dealloc{
    [[NSNotificationCenter defaultCenter] removeObserver:self];
}