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为什么我的类中的init块在使用改型时未被触发?

retrofit2 kotlin android

-1

Alexa289 · 技术社区 · 7 年前

因此,我将从服务器获得如下JSON:

{
    "success": "1",
    "data": [
        {
            "id": 1,
            "title": "1",
            "url": "5",
            "image": "resources/assets/images/banner_images/1548316546.mitra lakuin.png",
            "type": "category"
        },
        {
            "id": 2,
            "title": "2",
            "url": "5",
            "image": "resources/assets/images/banner_images/1548316605.mobile banner_-02 (1).png",
            "type": "category"
        },
        {
            "id": 4,
            "title": "4",
            "url": "5",
            "image": "resources/assets/images/banner_images/1547010221.gratis ongkir.png",
            "type": "category"
        },
        {
            "id": 5,
            "title": "Customer",
            "url": "5",
            "image": "resources/assets/images/banner_images/1548316659.customer service.png",
            "type": "category"
        }
    ],
    "message": "Banners are returned successfull."
}

我创建了2个类,以便将JSON转换为Banner对象。

// 1.
class BannerData(val message : String, val success : String, val data : List<Banner>) {}

// 2.

class Banner(id: Int, imageURL: String) {

    @SerializedName("image")
    var imageURL : String
    val id : Int

    init {
        Log.i("testX","triggered")

        this.id = id

        // The code below is used to add percent encoding to URL from server

        val unformattedFullPath = "${Endpoint.lakuin}/$imageURL"
        val formattedFullPath = URLConverterService.addingPercentEncoding(unformattedFullPath)
        this.imageURL = formattedFullPath

    }

}

改装界面如下所示:

    @GET("/app/getbanners")
    fun getBanners(): Call<BannerData>

object RetrofitHandler {

    private val loggingInterceptor = HttpLoggingInterceptor().setLevel(HttpLoggingInterceptor.Level.BODY)

    private val okHttpClient = OkHttpClient.Builder()
        .callTimeout(7,TimeUnit.SECONDS)
        .addInterceptor(loggingInterceptor)
        .build()

    private var retrofit = Retrofit.Builder()
        .baseUrl(Endpoint.lakuin) // default is set to lakuinAPI
        .addConverterFactory(GsonConverterFactory.create())
        .client(okHttpClient)
        .build()


    fun <T> getInstance(APIType: Class<T>) : T {
        // baseURL should be change later, if there is more than one API, ex: GoogleMapAPI, LakuinAPI etc
        return retrofit.create(APIType)
    }

}

我的问题是。。。。。

从上面的JSON可以看出,图像URL不完整,我想转换图像URL

from:“resources/bla.png”

成为: http://xxxx.com/resources/blablabla.png "

Banner 班

但是它似乎是应用程序中的init块 横幅 Log.i("testX","triggered") 从不在日志中显示

我实际上可以创建Banner对象,但imageURL与JSON完全相同,这意味着init块永远不会被触发

2 回复 | 直到 7 年前

Maksim Novikov 7 年前

如果您将“改装”设置为使用Gson库作为序列化/反序列化对象的库 addConverterFactory(GsonConverterFactory.create(gson)) , Gson 默认情况下,它不使用构造函数或init函数 instantiate an object and set its fields via reflection 我猜你的init块被跳过了,看看要了解库是否可以配置为不跳过 init 作用

Taras Parshenko 7 年前

只需将url包装在单独的类中

data class EndPointUrl(val url: String)

创建一个类并扩展它 JsonDeserializer 和 JsonSerializer EndPointUrl 反之亦然

class EndPointUrlSerializer : JsonDeserializer<EndPointUrl>, JsonSerializer<EndPointUrl> {

    @Throws(JsonParseException::class)
    override fun deserialize(
            json: JsonElement,
            type: Type,
            context: JsonDeserializationContext
    ) = EndPointUrl("${Endpoint.lakuin}/${json.asString}")

    override fun serialize(
            src: EndPointUrl,
            type: Type,
            context: JsonSerializationContext
    ) = JsonPrimitive(src.url)
}

在gson对象中注册序列化程序:

val gson = GsonBuilder()
                 .registerTypeAdapter(EndPointUrl::class.java, EndPointUrlSerializer())
                 .create()

在改装中使用此gson对象:

val retrofit = Retrofit.Builder()
                   .baseUrl(BASE_URL)
                   .addConverterFactory(GsonConverterFactory.create(gson))
                   .build()

现在你可以把 端点URL 对于您的响应对象:

data class Banner(id: Int, imageURL: EndPointUrl)