保存/加载IOS数据

我一直在尝试让我的应用程序保存和加载应用程序中的一组数组中的数据，奇怪的是，当应用程序终止（完全关闭）时，数据在重新启动时似乎没有加载，我查看了很多帖子、教程等，但我似乎无法让它工作，我在应用程序上有两个测试按钮，用于触发保存和加载方法，还有一个按钮用于清除记录。当我使用这些按钮进行测试时，它工作正常，数据保存和加载正确

我当前的设置如下：

• 我在supporting files目录中有一个名为data.plist的plist文件，在这个文件中，我有各种数组，索引0中的数据与全局数据类创建自身实例时初始化的数据相同

我的保存代码：

- (void)saveData{

    // get paths from root direcory
    NSArray *paths = NSSearchPathForDirectoriesInDomains (NSDocumentDirectory, NSUserDomainMask, YES);
    // get documents path
    NSString *documentsPath = [paths objectAtIndex:0];
    // get the path to our Data/plist file
    NSString *plistPath = [documentsPath stringByAppendingPathComponent:@"data.plist"];

    // create dictionary with arrays and their corresponding keys
    NSDictionary *plistDict = [NSDictionary dictionaryWithObjects: [NSArray arrayWithObjects: personalitySliderValue, looksSliderValue, humourSliderValue, chemistrySliderValue, emptySlider, notesValues,nameValues, noValues, ratingValues, nil] forKeys:[NSArray arrayWithObjects: @"personality", @"looks", @"humour", @"chemistry",@"empty",@"notes",@"name",@"no",@"rating", nil]];

    NSString *error = nil;
    // create NSData from dictionary
    NSData *plistData = [NSPropertyListSerialization dataFromPropertyList:plistDict format:NSPropertyListXMLFormat_v1_0 errorDescription:&error];

    // check if plistData exists
    if(plistData)
    {
        // write plistData to our Data.plist file
        [plistData writeToFile:plistPath atomically:YES];
    }
    else
    {
        NSLog(@"Error in saveData: %@", error);
    }

}

我的加载代码：

- (void)loadData{

    // get paths from root direcory
    NSArray *paths = NSSearchPathForDirectoriesInDomains (NSDocumentDirectory, NSUserDomainMask, YES);
    // get documents path
    NSString *documentsPath = [paths objectAtIndex:0];
    // get the path to our Data/plist file
    NSString *plistPath = [documentsPath stringByAppendingPathComponent:@"data.plist"];

    // check to see if data.plist exists in documents
    if (![[NSFileManager defaultManager] fileExistsAtPath:plistPath])
    {
        // if not in documents, get property list from main bundle CHECK D capitalisation
        plistPath = [[NSBundle mainBundle] pathForResource:@"data" ofType:@"plist"];
    }

    // read property list into memory as an NSData object
    NSData *plistXML = [[NSFileManager defaultManager] contentsAtPath:plistPath];
    NSString *errorDesc = nil;
    NSPropertyListFormat format;
    // convert static property list into dictionary object
    NSDictionary *dictionaryTemp = (NSDictionary *)[NSPropertyListSerialization propertyListFromData:plistXML mutabilityOption:NSPropertyListMutableContainersAndLeaves format:&format errorDescription:&errorDesc];
    if (!dictionaryTemp)
    {
        NSLog(@"Error reading plist: %@, format: %d", errorDesc, format);
    }
    // assign values
    personalitySliderValue = [NSMutableArray arrayWithArray:[dictionaryTemp objectForKey:@"personality"]];
    looksSliderValue = [NSMutableArray arrayWithArray:[dictionaryTemp objectForKey:@"looks"]];
    humourSliderValue = [NSMutableArray arrayWithArray:[dictionaryTemp objectForKey:@"humour"]];
    chemistrySliderValue = [NSMutableArray arrayWithArray:[dictionaryTemp objectForKey:@"chemistry"]];
    emptySlider = [NSMutableArray arrayWithArray:[dictionaryTemp objectForKey:@"empty"]];
    notesValues = [NSMutableArray arrayWithArray:[dictionaryTemp objectForKey:@"notes"]];
    nameValues = [NSMutableArray arrayWithArray:[dictionaryTemp objectForKey:@"name"]];
    noValues = [NSMutableArray arrayWithArray:[dictionaryTemp objectForKey:@"no"]];
    ratingValues = [NSMutableArray arrayWithArray:[dictionaryTemp objectForKey:@"rating"]];

}

最后是应用程序委托方法：

- (void)applicationDidEnterBackground:(UIApplication *)application
{

    // Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later.
    // If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.


    // save the app data

    [[GlobalData sharedGlobalData]saveData];
    NSLog(@"save method run");


}

- (void)applicationWillEnterForeground:(UIApplication *)application
{
    // Called as part of the transition from the background to the inactive state; here you can undo many of the changes made on entering the background.

    // load the app data

    [[GlobalData sharedGlobalData]loadData];
    NSLog(@"load method run");
}

---

这真的让我毛骨悚然，所以任何帮助都会很棒

您可以在此应用程序委托方法中在启动时加载数据：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
   ....
   [[GlobalData sharedGlobalData] loadData];
}

---

您可以在此应用程序委派方法中在启动时加载数据：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
   ....
   [[GlobalData sharedGlobalData] loadData];
}

---

正如用户1885297所说，将其加载到

didfishlaunchingwithoptions

。这样，您就可以确信它会在用户界面出现之前加载。另外，如果您删除了对

NSData

的引用，只需使用

NSDictionary

实例方法

writeToFile

保存，并使用class方法

dictionaryWithContentsOfFile

加载，就可以简化代码。谢谢Rob，我可能也会进行上述更改，我很难让它正常工作，所以我使用了一个可能有点过时的教程。正如用户1885297所说，在

didfishlaunchingwithoptions

中加载它。这样，您就可以确信它会在用户界面出现之前加载。另外，如果您删除了对

NSData

的引用，只需使用

NSDictionary

实例方法

writeToFile

保存，并使用class方法

dictionaryWithContentsOfFile

加载，就可以简化代码。谢谢Rob，我可能也会进行上述更改，我很难让它正常工作，所以我最终使用了一个可能有点过时的教程。