使用Messenger进行进程通信

android no

1，创建服务端进程

class MessengerService : Service() {
    private val TAG = "--${MessengerService::class.java.simpleName}--"
    private val messageHandler = Messenger(object : Handler() {
        override fun handleMessage(msg: Message) {
            when (msg.what) {
                Constants.FROM_CLIENT.value -> {
                    //1，打印接受到的消息
                    Log.e(TAG, "receive message from client:${msg.data.getString("msg")}")
                    //2，回复消息
                    var client = msg.replyTo
                    var replyMessage = Message.obtain()
                    replyMessage.what = Constants.FROM_SERVICE.value
                    val data = Bundle()
                    data.putString("reply", "Nice to meet you")
                    replyMessage.data = data
                    client.send(replyMessage)
                }
                else -> {
                }
            }
        }
    })
    override fun onBind(intent: Intent?): IBinder = messageHandler.binder
}

2，创建客户端进程

class MainActivity : AppCompatActivity() {
    private val TAG = "--${MainActivity::class.java.simpleName}--"
    //连接成功后获得，用于发送消息给服务端
    private var sender: Messenger? = null
    //将此对象传递给服务端可以接受并处理服务端发送的消息
    private val messageHandler = Messenger(object : Handler() {
        override fun handleMessage(msg: Message) {
            when (msg.what) {
                Constants.FROM_SERVICE.value -> {
                    Log.e(TAG, "receive message from Service:${msg.data.getString("reply")}")
                }
                else -> {
                }
            }
        }
    })
    private val conn = object : ServiceConnection {
        override fun onServiceDisconnected(name: ComponentName?) {
        }
        override fun onServiceConnected(name: ComponentName?, service: IBinder?) {
            //一旦连接成功就向服务器发送消息
            this@MainActivity.sender = Messenger(service)
            val msg = Message.obtain()
            msg.what = Constants.FROM_CLIENT.value
            val data = Bundle()
            data.putString("msg", "hello! I'm client")
            msg.data = data
            //如果需要接受服务端的回复消息的话就必须将处理器传递给服务端
            msg.replyTo = messageHandler
            this@MainActivity.sender?.send(msg)
        }
    }
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        //准备建立连接
        val intent = Intent()
        intent.action = "myService"
        bindService(intent, conn, Context.BIND_AUTO_CREATE)
    }
    override fun onDestroy() {
        unbindService(conn)
        super.onDestroy()
    }
}

注意：由于服务端是Service所以必须要在清单文件中注册

        <service
            android:name=".MessengerService"
            android:process=":remote">
            <intent-filter>
                <action android:name="myService" />
            </intent-filter>
        </service>