使用[popviewcontroller]传回数据，然后重新加载数据 [英] Pass back data using [popviewcontroller], and reload data
问题描述
在上面提供的图片中，显示了三个视图控制器.
In the picture provided above, shows three view controllers.
让我们按照显示顺序依次调用视图控制器 A ， B 和 C .
Let's call the view controllers A, B, and C in the order they're displayed.
View Controller A 通过单击表格单元格来传递已解析的jSON数据.这将填满总销售，折扣等".使用 prepareForSegue 方法在 View Controller B 中的字符串/标签.
View Controller A passes parsed jSON data by clicking on the table cell. This fills up the "total sales, discounts, etc." strings/labels inside of the View Controller B using a prepareForSegue method.
此数据基于开始时间/结束时间，并且执行segue时的默认参数会提供当日上午8点到晚上10点之间的信息.
解析字符串看起来像这样
This data is based on a start time/end time and the default parameter when performing the segue gives information from 8 AM to 10 PM of the current day.
The parsing string looks like this
NSDate *currentDate = [NSDate date];
NSDateFormatter *dateformatter = [[NSDateFormatter alloc] init];
[dateformatter setDateFormat:@"YYYY-MM-dd"];
NSString *theDate = [dateformatter stringFromDate: currentDate];
NSString *salesStr = @"http://";
salesStr = [salesStr stringByAppendingString:host];
salesStr = [salesStr stringByAppendingString:@":8080/sales.php?password="];
salesStr = [salesStr stringByAppendingString:pass];
salesStr = [salesStr stringByAppendingString:@"&db="];
salesStr = [salesStr stringByAppendingString:db];
salesStr = [salesStr stringByAppendingString:@"&sdate="];
salesStr = [salesStr stringByAppendingString:theDate];
salesStr = [salesStr stringByAppendingString:@"%2008:00:00&edate="];
salesStr = [salesStr stringByAppendingString:theDate];
salesStr = [salesStr stringByAppendingString:@"%2022:00:00"];
在 View Controller B 中，您会看到一个标记为"开始时间"的按钮.此按钮将启动推送服务到 View Controller C .在这个新的视图控制器中，您可以选择日期和时间，日期和时间将显示在日期选择器上方的UILabel中.日期选择器下方的按钮是IBAction，并使用
Inside of the View Controller B, you can notice a button labeled "Start Time". This button initiates a push segue to View Controller C. In this new view controller, you are able to select a date and time and it is displayed in the UILabel above the date picker. The button below the date picker is an IBAction and uses
[self.navigationController popViewControllerAnimated:YES];
我的问题是: 如何在 View Controller C 中选择日期/时间，按下按钮，然后发送该日期/时间位于UILabel中的信息添加到 View Controller B ，以便可以用来更新已解析的信息?
My question is: How am I able to select a date/time in View Controller C, press a button, and send that information located in the UILabel to View Controller B so it can be used to update the parsed information?
我想到的一种方法是让按钮设置为 View Controller B ，然后根据日期/时间选择重新解析信息，但这只会导致过多的结果导航控制器堆叠"对我来说似乎效率不高.
One way I could think of doing this is to have the button segue to View Controller B, and RE-PARSE the information based on the date/time selection, but that would just cause too much 'navigation controller stacking' and just doesn't seem efficient to me.
任何建议都值得赞赏.
推荐答案
Hacker的方法可行.
Hacker's approach would work.
Apple的文档提出了一种稍有不同的技术.使用一种视图控制器C可以用来与视图控制器B进行通信的方法来定义一个简单的协议.
Apple's documentation suggests a slightly different technique. Define a simple protocol with a method that view controller C can use to communicate with view controller B.
然后为视图控制器C提供符合该协议的委托属性.
Then give view controller C a delegate property that conforms to that protocol.
在您的prepareForSegue方法中，将自己设置为视图控制器C的委托.
In your prepareForSegue method, set yourself as view controller C's delegate.
然后，在视图控制器C中，当用户更改日期并单击按钮时，调用委托方法以通知视图控制器B用户在您弹出自己之前更改了日期值.
Then, in view controller C, when the user changes the date and clicks the button, invoke a delegate method to notify view controller B that the user changed the date value before popping yourself.
我建议也添加一个取消按钮，以便用户可以放弃所做的更改.在这种情况下，您只需要在弹出之前跳过调用委托方法即可.
I would suggest adding a cancel button as well, so the user can discard their changes. In that case, you just would skip calling the delegate method before popping.
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