objective-c - 错误Maddage : expected expression? [du

This question already has answers here:

Can I declare variables inside an Objective-C switch statement?

(6个答案)

PrepareForSegue mystery

(3个答案)

6年前关闭。

我认为这可能是一个愚蠢的错误，但我无法弄清楚。谁能告诉我我想念什么？

-(void) receiveRecommendData {
 //receive data//
 NSURL *getResultUrl = [NSURL URLWithString:@"http://phdprototype.tk/getResultData.php"];

 NSData *data = [NSData dataWithContentsOfURL:getResultUrl];

 [self getData:data];

 NSDictionary *jsonToDict = json[0]; //[json objectAtIndex:0];

 int pageNumber = [[jsonToDict objectForKey:@"recommendData"]intValue];

 switch (pageNumber) {
     case 0:
         UIViewController *controller = [self.storyboard instantiateViewControllerWithIdentifier:@"Collection_01ViewController"];
         break;
     case 1:
         UIViewController *controller = [self.storyboard instantiateViewControllerWithIdentifier:@"Collection_01ViewController"];
         break;
     case 2:
          UIViewController *controller = [self.storyboard instantiateViewControllerWithIdentifier:@"Collection_02ViewController"];
          break;
     case 3:
          UIViewController *controller = [self.storyboard instantiateViewControllerWithIdentifier:@"Collection_03ViewController"];
         break;
     default:
         break;
 }
}

错误发生在

UIViewController *controller = [self.storyboard instantiateViewControllerWithIdentifier:@"Collection_01ViewController"];

最佳答案

您不能将变量声明为case部分的第一行。只需加括号...

switch (pageNumber) {
  case 0: {
     UIViewController *controller = [self.storyboard instantiateViewControllerWithIdentifier:@"Collection_01ViewController"];
     break;
  }
  case 1: {
     UIViewController *controller = [self.storyboard instantiateViewControllerWithIdentifier:@"Collection_01ViewController"];
     break;
  }
  case 2:  //etc

关于objective-c - 错误Maddage : expected expression? [duplicate]，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/22138670/