Swift下将网络返回json数据转换成struct
假如网络请求返回的数据结构是一个深层嵌套的Json
首先要通过key-value取出这个json中的数据源
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 | // 将返回的json字符串转Dictorylet json = """{ "name": "jack", "age": 20, "description": "A student."}""".data(using: .utf8)!if let jsonData = jsonString.data(using: .utf8) { do { let json = try JSONSerialization.jsonObject(with: jsonData, options: []) if let dictionary = json as? [String: Any], let key2 = dictionary["key2"] as? [String: Any], let innerKey2 = key2["key2"] as? [String: Any], let value = innerKey2["key1"] as? String { print(value) // 输出"value3" } } catch { print("解析JSON数据失败：(error)") }} |
数模转换
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 | // 定义数据类型，遵守Codable协议// 注意定义的类型与接口返回对应，否则JSONSerialization时崩溃// Struct模型可以根据json中的数据关系对应嵌套struct ContactSimpleModel: Codable { var relation: String var name: String struct ContactSimpleModel1: Codable { var relation: String var name: String struct ContactSimpleModel2: Codable { var relation: String var name: String } }} |
字典与struct互相转换
将字典转换成struct模型
根据网络返回的Dictory，从里面取出数组widgets: Array<[String: Any]>
1.map遍历数组，拿到每一个数组元素字典
2.处理每个元素，先使用JSONSerialization.data(withJSONObject:将字典转成data，
3.再使用JSONDecoder().decode(ContactSimpleModel.self, from: data)将data转成struct结构体。
4.使用struct模型
1 2 3 4 5 6 7 | let decoder = JSONDecoder()let resList = try widgets.map { (item) -> AdJsonModel in let data = try JSONSerialization.data(withJSONObject: item, options: []) let res = try decoder.decode(AdJsonModel.self, from: data) return res}return resList |
struct模型转字典
也可以通过给Encodable协议加默认实现，提供便捷Struct转字典方法
1 2 3 4 5 6 7 8 9 10 11 12 13 | // 扩展 Encodable 协议extension Encodable { var dictionary: [String: Any]? { if let data = try? JSONEncoder().encode(self) { if let dict = try? JSONSerialization.jsonObject(with: data) as? [String: Any] { return dict } return nil } return nil }} |
Struct本地缓存
假如没有使用数据库，通过UserDefaults或者Plist文件保存。
使用data进行保存到UserDefaults
1 2 3 4 5 6 7 8 9 10 11 12 13 | struct Person: Codable { var name: String var age: Int}var people = [Person(name: "John", age: 30), Person(name: "Mary", age: 25)]//转成data保存let data = try! JSONEncoder().encode(people)UserDefaults.standard.set(data, forKey: "peopleData")//取if let data = UserDefaults.standard.data(forKey: "peopleData") { let people = try! JSONDecoder().decode([Person].self, from: data)} |
使用Dictionary保存到Plist文件
本地文件处理
路径判断，创建目录用Url.path
创建目录案例
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 | lazy var adListDirPath: String? = { let documentDic = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first let adUrl = documentDic?.appendingPathComponent(":ad") if let adUrlSub = adUrl { var isDic: ObjCBool = ObjCBool(false) // 判断adUrlSub.path路径是否存在，如果是文件路径则isDic=false, 如果是目录路径isDic=true if FileManager.default.fileExists(atPath: adUrlSub.path, isDirectory: &isDic) && isDic.boolValue { return adUrlSub.absoluteString } do { // 如果路径不存在，则创建本地路径，withIntermediateDirectories: true表示如果路径中间有未创建的，则把中间的目录也创建 try FileManager.default.createDirectory(at: adUrlSub, withIntermediateDirectories: true, attributes: nil) return adUrlSub.absoluteString } catch { Logger.error(":adDataManager", content: error.localizedDescription) return nil } } return nil}() |
写文件要用Url.absoluteString
swift中保存plist文件，使用NSDictionary进行保存
1 2 3 4 5 6 7 8 9 10 11 12 | 1.先删除历史文件 do { try FileManager.default.removeItem(at: filePathUrl) return true} catch { Logger.error(":adDataManager", content: error.localizedDescription) return false}2.保存新文件NSDictionary(object: adList, forKey: adListRootKey).write(to: filePathUrl, atomically: true)3.读取本地文件let dict = try NSDictionary(contentsOf: filePathUrl, error: ()) |
zip文件解压
1 2 3 4 5 6 7 8 9 | func unzipFile() { let zipPath = "/path/to/zip/file" let destinationPath = "/path/to/destination/folder" do { try ZipArchive.unzipFile(atPath: zipPath, toDestination: destinationPath) } catch { print("Error unzipping file: (error.localizedDescription)") }} |
先缓存后使用，提高用户体验
SDWebImage的先预下载图片，等启动时直接使用缓存的方法
1 2 3 4 5 6 7 8 | //0.自定义设置缓存大小URLCache.shared = URLCache(memoryCapacity: 10 * 1024 * 1024, diskCapacity: 50 * 1024 * 1024, diskPath: nil)//1.缓存SDWebImage批量下载图片SDWebImagePrefetcher.shared().prefetchURLs方法下载的图片本地路径默认是Library/Caches/com.hackemist.SDWebImageCache.default目录下的缓存文件。可以通过SDWebImageManager.shared().imageCache.diskCachePath方法获取具体路径。//2.使用在UIImageView加载图片时，使用AAImageView.sd_setImage(with: url, placeholderImage: nil)进行价值 |
1 2 | //3.删除缓存SDWebImageManager.shared.imageCache.removeImage(forKey: $0, cacheType: SDImageCacheType.all) |
注意：
对于可选类型的数组，如果没有拆包就map, 那么闭包的入参是拆包的数组
1 2 3 4 | let list = dict[adListRootKey] as? Array<[String: Any]>if let listSub = list { let decoder = JSONDecoder() let resList = listSub.map { (item) -> AdJsonModel? in |