【Kotlin】socket ping 判斷是否連上網際網路

2023.06.01
ping 的回應速度極快，還可指定等待 timeout 的時間限制，目前為止找到的最佳解

app 層級 build.gradle

 
android {
    ...
    ...
    
    buildFeatures {
        viewBinding true
    }
}
 
dependencies {
    ...
    ...
    
    implementation("org.jetbrains.kotlinx:kotlinx-coroutines-android:1.6.4")
}
 

AndroidManifest.xml

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

activity_main.xml

 
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">
 
    <TextView
        android:id="@+id/lblHello"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello World!"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        android:onClick="pingDuration"
        />
 
</androidx.constraintlayout.widget.ConstraintLayout>
 

MainActivity.kt

 
...
...
 
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.view.View
import kotlinx.coroutines.CoroutineScope
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.Job
import kotlinx.coroutines.launch
import java.net.InetSocketAddress
import java.net.Socket
import java.text.SimpleDateFormat
import java.util.Date
import java.util.Locale
 
 
class MainActivity : AppCompatActivity() {
    private lateinit var binding: ActivityMainBinding
 
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        binding = ActivityMainBinding.inflate(layoutInflater)
        val view = binding.root
        setContentView(view)
        
        pingDuration()
    }
 
 
    // 偵測 internet 連線狀況
    fun pingDuration() {
        val mScope = CoroutineScope(Job() + Dispatchers.IO)
        mScope.launch(Dispatchers.IO) {
            var sDuration = ""
            try {
                val a1 = Date()
                val timeoutMs = 1000    // 設定 timeout 為 1 秒
                val socket = Socket()
                val socketAddress = InetSocketAddress("8.8.8.8", 53)
                socket.connect(socketAddress, timeoutMs)
                socket.close()
                val a2 = Date()
 
                val durationMillis = a2.time - a1.time    // 平均小於 0.07 秒
                val hours = durationMillis / (1000 * 60 * 60)
                val minutes = durationMillis % (1000 * 60 * 60) / (1000 * 60)
                val seconds = durationMillis % (1000 * 60) / 1000
                val millis = durationMillis % 1000
                sDuration = String.format("%02d:%02d:%02d.%03d", hours, minutes, seconds, millis)
            } catch (e: Exception) {
                sDuration = "斷網 -- "+e.message
            }
            
            runOnUiThread {
                binding.lblHello.text = sDuration
            }
        }
    }
}