Add DownloadService.

retrofitLib/src/main/AndroidManifest.xml

@@ -1,2 +1,12 @@
+<?xml version="1.0" encoding="utf-8"?>
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
-    package="com.zeropercenthappy.retrofitutil" />
+    package="com.zeropercenthappy.retrofitutil">
+
+    <application>
+        <service
+            android:name=".service.download.DownloadService"
+            android:exported="false"
+            android:process=":ZphDownloadService" />
+    </application>
+
+</manifest>

retrofitLib/src/main/java/com/zeropercenthappy/retrofitutil/service/download/DownloadApi.kt

@@ -0,0 +1,11 @@
+package com.zeropercenthappy.retrofitutil.service.download
+
+import okhttp3.ResponseBody
+import retrofit2.http.GET
+import retrofit2.http.Url
+
+interface DownloadApi {
+
+    @GET
+    suspend fun download(@Url url: String): ResponseBody
+}

retrofitLib/src/main/java/com/zeropercenthappy/retrofitutil/service/download/DownloadService.kt

@@ -0,0 +1,73 @@
+package com.zeropercenthappy.retrofitutil.service.download
+
+import android.app.ActivityManager
+import android.app.IntentService
+import android.content.Context
+import android.content.Intent
+import com.zeropercenthappy.retrofitutil.RetrofitBuilder
+import com.zeropercenthappy.utilslibrary.utils.FileUtils
+import com.zeropercenthappy.utilslibrary.utils.ZPHLogger
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.runBlocking
+import java.io.File
+import java.io.Serializable
+
+private const val EXTRA_DOWNLOAD_MAP = "DownloadService.download.map"
+
+/**
+ * Start a download service running in a independent process.
+ *
+ * Warning: The result of download is not reliable. Because download task may be terminated in progress.
+ *
+ * So you have to check the file integrity before use it.
+ */
+class DownloadService : IntentService("DownloadService"), ZPHLogger {
+
+    private lateinit var api: DownloadApi
+    private lateinit var downloadMap: Map<String, File>
+    private lateinit var downloadTask: CoroutineScope
+
+    companion object {
+        @JvmStatic
+        fun startDownloadTask(context: Context, downloadMap: Map<String, File>) {
+            val intent = Intent(context, DownloadService::class.java)
+            intent.putExtra(EXTRA_DOWNLOAD_MAP, downloadMap as Serializable)
+            context.startService(intent)
+        }
+
+        @JvmStatic
+        fun stopDownloadTask(context: Context) {
+            val am = context.getSystemService(Context.ACTIVITY_SERVICE) as ActivityManager
+            val processes = am.runningAppProcesses
+            for (process in processes) {
+                if (process.processName == "${context.packageName}:ZphDownloadService") {
+                    android.os.Process.killProcess(process.pid)
+                    break
+                }
+            }
+        }
+    }
+
+    override fun onCreate() {
+        super.onCreate()
+        api = RetrofitBuilder()
+            .baseUrl("http://localhost/")
+            .build(this)
+            .create(DownloadApi::class.java)
+    }
+
+    @Suppress("UNCHECKED_CAST")
+    override fun onHandleIntent(intent: Intent) {
+        downloadMap = intent.getSerializableExtra(EXTRA_DOWNLOAD_MAP) as Map<String, File>
+        download()
+    }
+
+    private fun download() = runBlocking {
+        downloadTask = this
+        for (url in downloadMap.keys) {
+            val destinationFile = downloadMap[url] ?: continue
+            val responseBody = api.download(url)
+            FileUtils.writeFileByIS(destinationFile, responseBody.byteStream(), false)
+        }
+    }
+}