Day 4 的時候跟大家分享在分析欄位的時候，可以思考物件如何設計。今天就正式進入我們怎麼把這些欄位放入物件裡面，首先，先給大家看一下星戰人物中，人物的描述完整的是長什麼樣子如下：

{
  "name": "Luke Skywalker",
  "height": "172",
  "mass": "77",
  "hair_color": "blond",
  "skin_color": "fair",
  "eye_color": "blue",
  "birth_year": "19BBY",
  "gender": "male",
  "homeworld": "https://swapi.dev/api/planets/1/",
  "films": [
    "https://swapi.dev/api/films/2/",
    "https://swapi.dev/api/films/6/",
    "https://swapi.dev/api/films/3/",
    "https://swapi.dev/api/films/1/",
    "https://swapi.dev/api/films/7/"
  ],
  "species": [
    "https://swapi.dev/api/species/1/"
  ],
  "vehicles": [
    "https://swapi.dev/api/vehicles/14/",
    "https://swapi.dev/api/vehicles/30/"
  ],
  "starships": [
    "https://swapi.dev/api/starships/12/",
    "https://swapi.dev/api/starships/22/"
  ],
  "created": "2014-12-09T13:50:51.644000Z",
  "edited": "2014-12-20T21:17:56.891000Z",
  "url": "https://swapi.dev/api/people/1/"
}

昨天也提到只想呈現某些資訊，這邊我再做個簡化，只針對以下幾個欄位去做物件解析：

{
  "name": "Luke Skywalker",
  "height": "172",
  "mass": "77",
  "birth_year": "19BBY",
  "gender": "male"
}

首先，先針對性別寫一個 enum，直接針對這個字串去做轉換，將來如果需要擴增新的性別，就不用整個物件做很大的更動。

enum class Gender(val type: String) {
    MALE("male"),
    FEMALE("female"),
    UNKNOWN("unknown"),
    NONE("n/a")
}

接著建立 Profile 物件

data class Profile(
    val name: String,
    val height: String,
    @SerializedName("mass") val weight: String,
    private val gender: String,
    @SerializedName("birth_year") val birthYear: String
) {
    val genderType: Gender
        get() {
            values().forEach {
                if (it.type == gender) {
                    return it
                }
            }
            return UNKNOWN
        }
}

當然建立物件之後，會想問那剛剛所使用的 enum 轉換正常嗎？其他欄位所輸出的資料是如預期呈現嗎？這時候在還沒建立網路層之前可以寫 unit test 驗證資料是否正確性。

class ProfileTest {

    @Test
    fun skyWalkerTest(){
        val input = "\n" +
                "{\n" +
                "  \"name\": \"Luke Skywalker\",\n" +
                "  \"height\": \"172\",\n" +
                "  \"mass\": \"77\",\n" +
                "  \"hair_color\": \"blond\",\n" +
                "  \"skin_color\": \"fair\",\n" +
                "  \"eye_color\": \"blue\",\n" +
                "  \"birth_year\": \"19BBY\",\n" +
                "  \"gender\": \"male\",\n" +
                "  \"homeworld\": \"https://swapi.dev/api/planets/1/\",\n" +
                "  \"films\": [\n" +
                "    \"https://swapi.dev/api/films/2/\",\n" +
                "    \"https://swapi.dev/api/films/6/\",\n" +
                "    \"https://swapi.dev/api/films/3/\",\n" +
                "    \"https://swapi.dev/api/films/1/\",\n" +
                "    \"https://swapi.dev/api/films/7/\"\n" +
                "  ],\n" +
                "  \"species\": [\n" +
                "    \"https://swapi.dev/api/species/1/\"\n" +
                "  ],\n" +
                "  \"vehicles\": [\n" +
                "    \"https://swapi.dev/api/vehicles/14/\",\n" +
                "    \"https://swapi.dev/api/vehicles/30/\"\n" +
                "  ],\n" +
                "  \"starships\": [\n" +
                "    \"https://swapi.dev/api/starships/12/\",\n" +
                "    \"https://swapi.dev/api/starships/22/\"\n" +
                "  ],\n" +
                "  \"created\": \"2014-12-09T13:50:51.644000Z\",\n" +
                "  \"edited\": \"2014-12-20T21:17:56.891000Z\",\n" +
                "  \"url\": \"https://swapi.dev/api/people/1/\"\n" +
                "}"
        val profile = Gson().fromJson(input, Profile::class.java)
        // determine the data
        Assert.assertEquals("Luke Skywalker", profile.name)
        Assert.assertEquals("172", profile.height)
        Assert.assertEquals("77", profile.weight)
        Assert.assertEquals("19BBY", profile.birthYear)
        Assert.assertEquals(Gender.MALE, profile.genderType)
    }
}

在 class 按下 run test 就可以看看自己的資料是否正確，當然也可以隨意改 gender 的值來驗證這些 enum 是不是有超出預期的狀況發生。有興趣的朋友可以直接拉下程式碼自行玩玩看