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ios - 核心数据内存崩溃

转载 作者：行者123 更新时间：2023-11-28 16:08:57 25 4
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我是第一次在我的项目中使用 Core Data，我觉得我的方法存在严重问题。我正在做的是从服务器获取数据(数据也包括 png)。将其保存在本地的核心数据中。然后在应用程序启动时，我将整个数据加载到一个数组中。然后在我需要的地方使用这个数组。我认为我采用了一种非常糟糕的方法。谁能指导我什么是更好的方法？我应该只在需要数据时查询核心数据，而不是在开始时将所有内容都加载到内存中吗？

当数据被填充到数组时，我可以看到 Xcode 中的内存增加，并且在达到某个值后，它崩溃了。

这是我保存数据的代码:

func saveDataLocally () {

    let moContext = ((UIApplication.shared.delegate) as! AppDelegate).managedObjectContext
    let entity = NSEntityDescription.entity(forEntityName: "FoodPlace", in: moContext)

    for foodPlaceData in self.downloadedData_ {
        let foodPlace = NSManagedObject(entity: entity!, insertInto: moContext) as! FoodPlace
        foodPlace.objectId = foodPlaceData.objectId_
        foodPlace.name = foodPlaceData.name_
        foodPlace.address = foodPlaceData.address_
        foodPlace.keywords = foodPlaceData.keywords_
        foodPlace.baseFavourites = Int64(foodPlaceData.baseFavourites_)
        foodPlace.startingTime = foodPlaceData.startingTime_
        foodPlace.endingTime = foodPlaceData.endingTime_
        foodPlace.category = foodPlaceData.category_
        foodPlace.basePrice = foodPlaceData.basePrice_
        foodPlace.dealTitle = foodPlaceData.dealTitle_
        foodPlace.versionNumber = Int64(foodPlaceData.versionNumber_)
        foodPlace.menuItems = NSKeyedArchiver.archivedData(withRootObject: foodPlaceData.menuItems_)
        foodPlace.location = NSKeyedArchiver.archivedData(withRootObject: foodPlaceData.location_)
        foodPlace.deals = NSKeyedArchiver.archivedData(withRootObject: foodPlaceData.deals_)
        foodPlace.foodPlacePhotos = NSKeyedArchiver.archivedData(withRootObject: foodPlaceData.foodPlacePhotos_)

        moContext.insert(foodPlace)
    }

    do {
        try moContext.save()
    }
    catch let error {
        print("error saving = \(error.localizedDescription)")
    }
}

其中 menuItems 是一个包含文本和 png 图像的 Dictionary。此外，deals 和 foodPlacePhotos 仅包含 png 图像。

获取代码如下:

func loadDataLocally () {
    let moContext = ((UIApplication.shared.delegate) as! AppDelegate).managedObjectContext
    let request = NSFetchRequest<NSFetchRequestResult>(entityName: "FoodPlace")

    do {
        let results = try moContext.fetch(request)
        let savedFoodPlaceData = results as! [FoodPlace]

        downloadedData_ = []

        for foodPlace in savedFoodPlaceData {
            let objectId = foodPlace.objectId
            let name = foodPlace.name
            let address = foodPlace.address
            let keywords = foodPlace.keywords
            let baseFavourites = foodPlace.baseFavourites
            let startingTime = foodPlace.startingTime
            let endingTime = foodPlace.endingTime
            let category = foodPlace.category
            let menuItems = NSKeyedUnarchiver.unarchiveObject(with: foodPlace.menuItems!) as? [Dictionary<String,AnyObject>]
            let location = NSKeyedUnarchiver.unarchiveObject(with: foodPlace.location!) as? Dictionary<String,Double>
            let deals = NSKeyedUnarchiver.unarchiveObject(with: foodPlace.deals!) as? [UIImage]
            let basePrice = Float(foodPlace.basePrice)
            let dealTitle = foodPlace.dealTitle
            let versionNumber = foodPlace.versionNumber
            let foodPlacePhotos = NSKeyedUnarchiver.unarchiveObject(with: foodPlace.foodPlacePhotos!) as? [UIImage]

            let data = FoodPlaceData(objectId: objectId!, name: name!, address: address!, category: category!, keywords: keywords!, baseFavourites: Int(baseFavourites), startingTime: startingTime!, endingTime: endingTime!, menuItems: menuItems!, location: location!, deals: deals!,basePrice: basePrice,dealTitle: dealTitle!,versionNumber: Int(versionNumber),foodPlacePhotos: foodPlacePhotos!)

            downloadedData_.insert(data, at: downloadedData_.count)
        }
    }
    catch let error {
        print("error fetching = \(error.localizedDescription)")
    }
}

下面是删除数据的代码:

func deleteAllLocalData () {
    let moContext = ((UIApplication.shared.delegate) as! AppDelegate).managedObjectContext

    let fetchRequest = NSFetchRequest<NSFetchRequestResult>(entityName: "FoodPlace")
    fetchRequest.returnsObjectsAsFaults = false

    do {
        let results = try moContext.fetch(fetchRequest)

        for managedObject in results {
            let managedObjectData : NSManagedObject = managedObject as! NSManagedObject
            moContext.delete(managedObjectData)
        }

        try moContext.save()

    } catch let error {
        print("Delete all data in FoodPlace error : \(error) \((error as NSError).userInfo)")
    }
}

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