前言:

  說到呼叫 API 的方法，那就一定會提到 Retrofit 這個無人不知，無人不曉的第三方的套件， 適用於 Android 和 Java 的類型安全HTTP 客戶端，功能強大且完整，好寫和好維護呀，廢話不多就用下去吧。
    

大綱 :

終於談到了Retrofit ， 那我們就看一下從第15天到第17天的MVVM 架構，綜合實作一下吧

build.gradle(app)

dependencies {
 implementation 'com.squareup.retrofit2:converter-gson:2.9.0'
 implementation 'com.squareup.retrofit2:retrofit:2.9.0'
 implementation "com.squareup.okhttp3:logging-interceptor:4.0.1"
 implementation "com.squareup.okhttp3:okhttp:4.9.0"
}

AndroidManifet.xml 宣告 INTERNET 權限

<uses-permission android:name="android.permission.INTERNET" />

建立Interface

interface FindWcApi {
@GET("{mLocal}?format=json&limit=5&api_key="+ API_KEY)
suspend fun getToilet( @Path(value = "mLocal") Local:String,@Query(value = "filters")  Latitude:String, @Query(value = "filters")  Longitude:String): Response<ToiletData>

companion object {
    const val OPENDATA_URL = "https://data.epa.gov.tw/api/v1/"
    const val API_KEY = "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
 }
}

建立Repository

class FindWcRepository(Local:String = "fac_p_07", Latitude:Double=24.9XXXX, Longitude:Double=121.5XXXX9) {
private val findWcApi: FindWcApi
var mLocal = Local
var mLatitude = Latitude
var mLongitude = Longitude
public val mApiInfo = ApiInfo(mLocal,mLatitude,mLongitude)

init {
    val loggingInterceptor = HttpLoggingInterceptor()
    println(loggingInterceptor.toString())
    loggingInterceptor.level = HttpLoggingInterceptor.Level.BODY
    val okHttpClientBuilder = OkHttpClient.Builder().addInterceptor {
        // This open API does not require any headers. This would be the
        // place to add headers for APIs that, for example require an API key.
        it.proceed(it.request().newBuilder().build())
    }
    val retrofit = Retrofit.Builder()
        .baseUrl(FindWcApi.OPENDATA_URL)
        .addConverterFactory(GsonConverterFactory.create())
        .client(okHttpClientBuilder.build())
        .build()
    findWcApi = retrofit.create(FindWcApi::class.java)
}


fun getToiletData(block: suspend (ToiletData) -> Unit) {

    runBlocking {
       
        val response = findWcApi.getToilet(mLocal,"Latitude,LE,"+mLatitude,"Longitude,LE,"+mLongitude)
        val result = response.body()
                   result?.let {
            block(it)
        }
    }
  }
}

**viewModel **

class Day21ViewModel:ViewModel() {

var toiletInfo = MutableLiveData<String>()
var toiletInfoResult: String = "查詢中"

fun getToiletInfo() {
    FindWcRepository().getToiletData {
        //var toiletInfo:String = ""
        if(!it.records.isEmpty()) {
            for(item in it.records.indices) {
                toiletInfoResult= toiletInfoResult+"公廁名稱: "+it.records.get(item).Name + " 公廁地址: " + it.records.get(item).Address+"\n"
            }
        }else{
            toiletInfoResult = "找不到資料或是資料有誤,如果還要找其他地方，請再問一次請問廁所在哪裏"
        }
        toiletInfo.postValue(toiletInfoResult)
    }
  }
}

Activity

   viewModel = ViewModelProvider(this).get(Day21ViewModel::class.java)

    viewModel.toiletInfo.observe(this){
        binding.TextviewResult.text = it
    }


 //onClick
  fun findwc(view: View) {
    viewModel.getToiletInfo()
  }

執行結果:

參考:

https://square.github.io/retrofit/
https://developer.android.com/jetpack
https://developer.android.com/topic/libraries/architecture/viewmodel
https://developer.android.com/topic/libraries/architecture/livedata