从每个视图控制器访问 NSArray [英] Access an NSArray from Every View Controller

问题描述

我有一个相当大的 NSArray，我必须在多个视图控制器中使用它.我从服务器获取数据，但我不想在用户打开新视图时总是下载它.

I have a quite big NSArray, that i have to use in several view controllers. I get the data from a server and i don't wanna download it always when the user opens a new view.

那么如何将其定义为全局变量"?

So how can i define it as a "global variable"?

我可以用 segues 来做，但没有它们就行不通.我试图在 DestinationViewController 中声明一个名为 dataToDestinationView 的数组，然后将它导入到 self.arrayToExport 所在的视图中并添加上面的行，但不起作用.我错过了什么吗?

I can do it with segues, but without them it's not working. I've tried to declare an array called dataToDestinationView in the DestinationViewController, then imported it to the view where the self.arrayToExport is and add the lines above, but doesn't worked. Do i missed something?

DestinationViewController  *dataToNew = [DestinationViewController alloc]init];       
dataToNew.dataToDestinationView = self.arrayToExport;

更新了我在 AppDelegate 中的尝试:

AppDelegate.h

AppDelegate.h

@property (nonatomic, strong) PNChannel *myChannel;

AppDelegate.m

AppDelegate.m

[PubNub requestHistoryForChannel:self.myChannel from:nil to:nil limit:100 reverseHistory:NO withCompletionBlock:^(NSArray *contentArray, PNChannel *channel, PNDate *fromDate, PNDate *toDate, PNError *error) {



+ (NSArray *)mySharedArray
{
    static NSArray *sharedArray = nil;
    if (sharedArray)
        return sharedArray;

    sharedArray = contentArray;
    return sharedArray;
}


}];

在这种情况下，我得到两个错误:Use of undeclared identifier 'self' 和 Expected identifier or '('.我不明白，因为 self.myChannel 在 .h 中声明，我在其他地方使用相同的块而没有标识符问题.

In this case i get two errors: Use of undeclared identifier 'self' and Expected identifier or '('. I don't understand it, because self.myChannel is declared in the .h and i'm using the same block elsewhere without the identifier problem.

第二次更新

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{

 //   [self.window makeKeyAndVisible];

    [PubNub setDelegate:self];

    PFUser *currentChannel = [PFUser currentUser];
    self.myChannel = [PNChannel channelWithName:currentChannel.username
         shouldObservePresence:YES];

}


- (void)getMessage {

    [PubNub requestFullHistoryForChannel:self.myChannel withCompletionBlock:^(NSArray *contentArray, PNChannel *channel, PNDate *fromDate, PNDate *toDate, PNError *error) {


        + (NSArray *)mySharedArray
        {
            static NSArray *sharedArray = nil;
            if (sharedArray)
                return sharedArray;

            sharedArray = contentArray;
            return sharedArray;
        }


        NSLog(@"mokus katona %@", contactArray);

    }];
}

推荐答案

在你的应用委托中，声明一个静态变量，以及一个读取它的方法:

Inside your app delegate, declare a static variable, and a method to read it:

static NSArray *_message = nil;

@implementation AppDelegate

+ (NSArray *)message
{
    if (_message)
        return _message;

    AppDelegate *appDelegate = [[UIApplication sharedApplication] delegate];
    [appDelegate getMessage];

    return nil;
}

- (void)getMessage {

  [PubNub requestFullHistoryForChannel:self.myChannel withCompletionBlock:^(NSArray *contentArray, PNChannel *channel, PNDate *fromDate, PNDate *toDate, PNError *error) {



      NSLog(@"mokus katona %@", contactArray);

      _message = contactArray;
  }];
}

@end

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