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วิธีดึงที่อยู่เต็มจาก Latitude และ Longitude ใน Android Kotlin

แปลงพิกัด GPS เป็นที่อยู่ (Reverse Geocoding)

ตัวอย่างนี้สาธิตวิธีใช้ Geocoder เพื่อแปลง Latitude/Longitude ให้เป็นที่อยู่เต็มใน Android โดยใช้ Kotlin พร้อมการขอสิทธิ์ Location

ขั้นตอนที่ 1: สร้างโปรเจกต์ใหม่

สร้างโปรเจกต์ Android ใหม่ใน Android Studio

ขั้นตอนที่ 2: เลย์เอาต์ (res/layout/activity_main.xml)

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="https://schemas.android.com/apk/res/android"
    xmlns:tools="https://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="16sp"
    tools:context=".MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="50dp"
        android:text="Tutorials Point"
        android:textAlignment="center"
        android:textColor="@android:color/holo_green_dark"
        android:textSize="32sp"
        android:textStyle="bold" />

    <Button
        android:id="@+id/btnShowAddress"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:text="Show Address" />

    <TextView
        android:id="@+id/tvAddress"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/btnShowAddress"
        android:layout_centerInParent="true"
        android:textColor="@android:color/background_dark"
        android:textSize="12sp"
        android:textStyle="bold" />

</RelativeLayout>

ขั้นตอนที่ 3: MainActivity.kt (จัดการ Permission และ UI)

import android.Manifest
import android.content.Intent
import android.content.pm.PackageManager
import android.location.Location
import android.location.LocationManager
import android.os.Bundle
import android.os.Handler
import android.os.Message
import android.provider.Settings
import android.widget.Button
import android.widget.TextView
import android.widget.Toast
import androidx.appcompat.app.AlertDialog
import androidx.appcompat.app.AppCompatActivity
import androidx.core.app.ActivityCompat
import androidx.core.content.ContextCompat

class MainActivity : AppCompatActivity() {
    private lateinit var btnShowAddress: Button
    private lateinit var tvAddress: TextView
    private lateinit var location: Location
    private lateinit var appLocationService: AppLocationService

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        title = "KotlinApp"
        
        tvAddress = findViewById(R.id.tvAddress)
        appLocationService = AppLocationService(this)
        btnShowAddress = findViewById(R.id.btnShowAddress)
        
        // ขอสิทธิ์ Location
        if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(this, arrayOf(Manifest.permission.ACCESS_FINE_LOCATION), 1)
        }
        
        btnShowAddress.setOnClickListener {
            location = appLocationService.getLocation(LocationManager.GPS_PROVIDER)!!
            val latitude = 13.1000727
            val longitude = 80.2126274
            val locationAddress = LocationAddress()
            locationAddress.getAddressFromLocation(latitude, longitude, applicationContext, GeoCodeHandler())
            showSettingsAlert()
        }
    }
    
    private fun showSettingsAlert() {
        AlertDialog.Builder(this).apply {
            setTitle("SETTINGS")
            setMessage("Enable Location Provider! Go to settings menu?")
            setPositiveButton("Settings") { _, _ ->
                startActivity(Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS))
            }
            setNegativeButton("Cancel") { dialog, _ -> dialog.cancel() }
            show()
        }
    }
    
    internal inner class GeoCodeHandler : Handler() {
        override fun handleMessage(message: Message) {
            val locationAddress = when (message.what) {
                1 -> message.data.getString("address") ?: ""
                else -> ""
            }
            tvAddress.text = locationAddress
        }
    }
    
    override fun onRequestPermissionsResult(requestCode: Int, permissions: Array<String>, grantResults: IntArray) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults)
        if (requestCode == 1 && grantResults.isNotEmpty() && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
            Toast.makeText(this, "Permission Granted", Toast.LENGTH_SHORT).show()
        } else {
            Toast.makeText(this, "Permission Denied", Toast.LENGTH_SHORT).show()
        }
    }
}

ขั้นตอนที่ 4: AppLocationService.kt

import android.annotation.SuppressLint
import android.app.Service
import android.content.Context
import android.content.Intent
import android.location.Location
import android.location.LocationListener
import android.location.LocationManager
import android.os.Bundle
import android.os.IBinder

open class AppLocationService(context: Context) : Service(), LocationListener {
    private var locationManager: LocationManager? = context.getSystemService(Context.LOCATION_SERVICE) as LocationManager
    private lateinit var location: Location
    
    companion object {
        private const val MIN_DISTANCE_FOR_UPDATE: Long = 10
        private const val MIN_TIME_FOR_UPDATE = 1000 * 60 * 2L
    }

    @SuppressLint("MissingPermission")
    fun getLocation(provider: String?): Location? {
        if (locationManager!!.isProviderEnabled(provider)) {
            locationManager!!.requestLocationUpdates(provider, MIN_TIME_FOR_UPDATE, MIN_DISTANCE_FOR_UPDATE.toFloat(), this)
            if (locationManager != null) {
                location = locationManager!!.getLastKnownLocation(provider)
                return location
            }
        }
        return null
    }
    
    override fun onLocationChanged(location: Location) {}
    override fun onProviderDisabled(provider: String) {}
    override fun onProviderEnabled(provider: String) {}
    override fun onStatusChanged(provider: String, status: Int, extras: Bundle) {}
    override fun onBind(arg0: Intent): IBinder? = null
}

ขั้นตอนที่ 5: LocationAddress.kt (Reverse Geocoding)

import android.content.Context
import android.location.Geocoder
import android.os.Bundle
import android.os.Handler
import android.os.Message
import android.util.Log
import java.io.IOException
import java.util.Locale

class LocationAddress {
    private val tag = "LocationAddress"
    
    fun getAddressFromLocation(latitude: Double, longitude: Double, context: Context, handler: Handler) {
        Thread {
            val geoCoder = Geocoder(context, Locale.getDefault())
            var result = ""
            
            try {
                val addressList = geoCoder.getFromLocation(latitude, longitude, 1)
                if (addressList != null && addressList.isNotEmpty()) {
                    val address = addressList[0]
                    val sb = StringBuilder()
                    for (i in 0 until address.maxAddressLineIndex) {
                        sb.append(address.getAddressLine(i)).append("\n")
                    }
                    sb.append(address.locality).append("\n")
                    sb.append(address.postalCode).append("\n")
                    sb.append(address.countryName)
                    result = sb.toString()
                }
            } catch (e: IOException) {
                Log.e(tag, "Unable connect to GeoCoder", e)
            } finally {
                val message = Message.obtain()
                message.target = handler
                message.what = 1
                val bundle = Bundle().apply {
                    putString("address", "Latitude: $latitude Longitude: $longitude\n\nAddress:\n$result")
                }
                message.data = bundle
                message.sendToTarget()
            }
        }.start()
    }
}

ขั้นตอนที่ 6: Manifest (ต้องมี Permission)

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="https://schemas.android.com/apk/res/android" package="app.com.q11">
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>
</manifest>

หมายเหตุ

  • Geocoder ต้องการ Internet และอาจไม่ทำงานบน Emulator
  • ควรใช้ FusedLocationProviderClient แทนสำหรับโปรเจกต์จริง
  • Android 10+ ต้องขอ Permission ระหว่างรัน (Runtime Permission)