android - IntentService 的依赖注入(inject)不起作用

Question

我想创建 TCP_Client，它在许多 Activity 中将数据发送到服务器。我决定使用依赖注入(inject)将所有相同配置的客户端注入(inject)到所有客户端。不幸的是，它在开始时停止工作。

我的应用程序模块

val appModule = module {
    single<ConnectionService> { ConnectionServiceTcp("192.168.0.1", 8888) }
}

主要应用

class MainApplication : Application() {

    override fun onCreate() {
        super.onCreate()
        startKoin {
            androidContext(this@MainApplication)
            androidLogger()
            modules(appModule)
        }
    }
}

class ConnectionServiceTcp(private val ipAddress: String, private val port : Int)
    : IntentService("TCP_CLIENT"), ConnectionService {

    private var client : Socket? = null

    override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
        super.onStartCommand(intent, flags, startId)
        return START_STICKY
    }

    override fun onHandleIntent(intent: Intent?) {
        startTcpServer()
    }

    private fun startTcpServer() {
        client = Socket(ipAddress, port)
    }


    override fun isConnectedToServer(): Boolean {
        Log.println(Log.INFO, null, "Adres = ${client?.localAddress} port = ${client?.localPort}")
        return false
    }

}

class MainActivity : AppCompatActivity() {

    private val connectionService : ConnectionService by inject()

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        startTcpServer()
    }

    private fun startTcpServer() {
        val serverTcp = Intent(this, ConnectionServiceTcp::class.java)
        startService(serverTcp)
    }

然后我收到

    java.lang.RuntimeException: Unable to instantiate service connection.impl.ConnectionServiceTcp: java.lang.InstantiationException: java.lang.Class<connection.impl.ConnectionServiceTcp> has no zero argument constructor

我找不到注入(inject)后台客户端发送 TCP 请求的方法

Answer 1

就像 Activities、Fragments 或其他一些平台组件一样，Android 系统暗示服务应该有一个单一的无参数构造函数。系统在 Service 类中查找默认构造函数并使用反射调用它。这就是为什么禁止添加非默认构造函数(即带参数的构造函数)的原因。

要将依赖项注入(inject)服务，您应该像在 Activity 中一样执行操作(声明一个字段并使用 by inject() 委托(delegate)注入(inject)它。因此最终代码如下所示:

class ConnectionServiceTcp()
    : IntentService("TCP_CLIENT"), ConnectionService {

    private val ipAddress: String by inject()
    private val port : Int by inject()
    private var client : Socket? = null

    override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
        super.onStartCommand(intent, flags, startId)
        return START_STICKY
    }

    override fun onHandleIntent(intent: Intent?) {
        startTcpServer()
    }

    private fun startTcpServer() {
        client = Socket(ipAddress, port)
    }

    override fun isConnectedToServer(): Boolean {
        Log.println(Log.INFO, null, "Adres = ${client?.localAddress} port = ${client?.localPort}")
        return false
    }
}