问数据报(UDP)接收器不工作-未接收广播数据包

EN

//Required includes
import android.os.Bundle
import android.os.StrictMode
import android.widget.Button
import android.widget.TextView
import androidx.appcompat.app.AppCompatActivity
import java.io.IOException
import java.net.*


class MainActivity : AppCompatActivity() {

    //declared variables
    private var clientThread: ClientThread? = null
    private var thread: Thread? = null
    private var tv:TextView? = null

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_new)

        //Create a thread so that the received data does not run within the main user interface
        clientThread = ClientThread()
        thread = Thread(clientThread)
        thread!!.start()

        // create a value that is linked to a button called (id) MyButton in the layout
        val buttonPress = findViewById<Button>(R.id.MyButton)
        tv = findViewById(R.id.rcvdData)
        tv!!.text = "Data Captured"

        //Create a listener that will respond if MyButton is clicked
        buttonPress.setOnClickListener{
            //send a UDP package as a test
            sendUDP("Hello")
        }
    }



    //************************************ Some test code to send a UDP package
    fun sendUDP(messageStr: String) {
        // Hack Prevent crash (sending should be done using a separate thread)
        val policy = StrictMode.ThreadPolicy.Builder().permitAll().build()
        StrictMode.setThreadPolicy(policy)  //Just for testing relax the rules...
        try {
            //Open a port to send a UDP package
            val socket = DatagramSocket()
            socket.broadcast = true
            val sendData = messageStr.toByteArray()
            val sendPacket = DatagramPacket(sendData, sendData.size, InetAddress.getByName(SERVER_IP), SERVERPORT)
            socket.send(sendPacket)
            println("Packet Sent")
        } catch (e: IOException) {
            println(">>>>>>>>>>>>> IOException  "+e.message)
        }
    }

    //************************************* Some test code for receiving a UDP package
    internal inner class ClientThread : Runnable {
        private var socket: DatagramSocket? = null
        private val recvBuf = ByteArray(1500)
        private val packet = DatagramPacket(recvBuf, recvBuf.size)
        // **********************************************************************************************
        // * Open the network socket connection and start receiving a Byte Array                        *
        // **********************************************************************************************
        override fun run() {

            try {
                //Keep a socket open to listen to all the UDP trafic that is destined for this port
                socket = DatagramSocket(CLIENTPORT)
                while (true) {
                    //Receive a packet
                    socket!!.receive(packet)  

                    //Packet received
                    println("Packet received from: " + packet.address.hostAddress)
                    val data = String(packet.data).trim { it <= ' ' }
                    println("Packet received; data: $data")
                    //Change the text on the main activity view
                    runOnUiThread { tv?.text = data }
                }
            }
            catch (e1: IOException) {
                println(">>>>>>>>>>>>> IOException  "+e1.message)
                socket?.close()
            }
            catch (e2: UnknownHostException) {
                println(">>>>>>>>>>>>> UnknownHostException  "+e2.message)
                socket?.close()
            }
            finally{
                socket?.close()
            }
        }
    }

    companion object {
        val CLIENTPORT = 3000
        val SERVERPORT = 3000
        val SERVER_IP = "192.168.8.102"
    }
}

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

buildscript {
    ext.kotlin_version = "1.5.0"
    repositories {
        google()
        mavenCentral()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:4.2.0'
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
    }
}

allprojects {
    repositories {
        google()
        mavenCentral()
    }
}

task clean(type: Delete) {
    delete rootProject.buildDir
}

plugins {
    id 'com.android.application'
    id 'kotlin-android'
}

android {
    compileSdkVersion 30
    buildToolsVersion "30.0.3"

    defaultConfig {
        applicationId "com.example.udptry1"
        minSdkVersion 23
        targetSdkVersion 30
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
    kotlinOptions {
        jvmTarget = '1.8'
    }
}

dependencies {
    implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
    implementation 'androidx.core:core-ktx:1.3.2'
    implementation 'androidx.appcompat:appcompat:1.2.0'
    implementation 'com.google.android.material:material:1.3.0'
    implementation 'androidx.constraintlayout:constraintlayout:2.0.4'
    testImplementation 'junit:junit:4.+'
    androidTestImplementation 'androidx.test.ext:junit:1.1.2'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.3.0'
}