使用 Kotlin 在 Android 上获取用户当前位置的最简单方法?
此示例演示了如何使用 Kotlin 在 Android 上获取用户当前位置。
步骤 1 − 在 Android Studio 中创建一个新项目,转到文件 ⇒ 新建项目,并填写所有必需的详细信息以创建新项目。
在 Gradle 中添加以下依赖项
implementation 'com.google.android.gms:play-services-location:17.0.0'
步骤 2 − 将以下代码添加到 res/layout/activity_main.xml 中。
<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:padding="4dp" tools:context=".MainActivity"> <TextView android:id="@+id/text" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerHorizontal="true" android:layout_marginTop="70dp" android:background="#008080" android:padding="5dp" android:text="TutorialsPoint" android:textColor="#fff" android:textSize="24sp" android:textStyle="bold" /> <TextView android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_below="@+id/text" android:layout_centerHorizontal="true" android:layout_marginTop="40dp" android:text="Get Current Location and City Name" android:textAlignment="center" android:textColor="@android:color/holo_orange_dark" android:textSize="24sp" android:textStyle="bold" /> <TextView android:id="@+id/textView" android:textColor="@android:color/background_dark" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerInParent="true" android:textSize="16sp" android:textStyle="bold" /> </RelativeLayout>
步骤 3 − 将以下代码添加到 src/MainActivity.kt 中
import android.Manifest import android.content.Intent import android.content.pm.PackageManager import android.location.Geocoder import android.location.Location import android.os.Bundle import android.os.Handler import android.os.ResultReceiver import android.util.Log import android.widget.TextView import android.widget.Toast import androidx.appcompat.app.AppCompatActivity import androidx.core.app.ActivityCompat import androidx.core.content.ContextCompat import com.google.android.gms.location.* class MainActivity : AppCompatActivity() { private lateinit var fusedLocationClient: FusedLocationProviderClient private val locationPermissionCode = 2 private lateinit var addressResultReceiver: LocationAddressResultReceiver private lateinit var currentAddTv: TextView private lateinit var currentLocation: Location private lateinit var locationCallback: LocationCallback override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_main) title = "KotlinApp" addressResultReceiver = LocationAddressResultReceiver(Handler()) currentAddTv = findViewById(R.id.textView) fusedLocationClient = LocationServices.getFusedLocationProviderClient(this) locationCallback = object : LocationCallback() { override fun onLocationResult(locationResult: LocationResult) { currentLocation = locationResult.locations[0] getAddress() } } startLocationUpdates() } private fun startLocationUpdates() { if ((ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED)) { ActivityCompat.requestPermissions(this, arrayOf(Manifest.permission.ACCESS_FINE_LOCATION), locationPermissionCode) } else { val locationRequest = LocationRequest() locationRequest.interval = 2000 locationRequest.fastestInterval = 1000 locationRequest.priority = LocationRequest.PRIORITY_HIGH_ACCURACY fusedLocationClient.requestLocationUpdates(locationRequest, locationCallback, null) } } private fun getAddress() { if (!Geocoder.isPresent()) { Toast.makeText(this@MainActivity, "Can't find current address, ", Toast.LENGTH_SHORT).show() return } val intent = Intent(this, GetAddressIntentService::class.java) intent.putExtra("add_receiver", addressResultReceiver) intent.putExtra("add_location", currentLocation) startService(intent) } override fun onRequestPermissionsResult(requestCode: Int, permissions: Array<out String>, grantResults: IntArray) { if (requestCode == locationPermissionCode) { if (grantResults.isNotEmpty() && grantResults[0] == PackageManager.PERMISSION_GRANTED) { Toast.makeText(this, "Permission Granted", Toast.LENGTH_SHORT).show() startLocationUpdates() } else { Toast.makeText(this, "Permission Denied", Toast.LENGTH_SHORT).show() } } } private inner class LocationAddressResultReceiver(handler: Handler) : ResultReceiver(handler) { override fun onReceiveResult(resultCode: Int, resultData: Bundle) { if (resultCode == 0) { Log.d("Address", "Location null retrying") getAddress() } if (resultCode == 1) { Toast.makeText(this@MainActivity, "Address not found, ", Toast.LENGTH_SHORT).show() } val currentAdd = resultData.getString("address_result") if (currentAdd != null) { showResults(currentAdd) } } } private fun showResults(currentAdd: String) { currentAddTv.text = currentAdd } override fun onResume() { super.onResume() startLocationUpdates() } override fun onPause() { super.onPause() fusedLocationClient.removeLocationUpdates(locationCallback) } }
步骤 4 − 创建一个新的 Kotlin 类 GetAddressFromIntentService.kt 并添加以下代码
import android.app.IntentService import android.content.Intent import android.location.Address import android.location.Geocoder import android.location.Location import android.os.Bundle import android.os.ResultReceiver import android.util.Log import java.util.* class GetAddressIntentService : IntentService(IDENTIFIER) { private var addressResultReceiver: ResultReceiver? = null override fun onHandleIntent(intent: Intent?) { val msg: String addressResultReceiver = Objects.requireNonNull(intent)!!.getParcelableExtra("add_receiver") if (addressResultReceiver == null) { Log.e("GetAddressIntentService", "No receiver, not processing the request further") return } val location = intent!!.getParcelableExtra<Location>("add_location") if (location == null) { msg = "No location, can't go further without location" sendResultsToReceiver(0, msg) return } val geoCoder = Geocoder(this, Locale.getDefault()) var addresses: List<Address>? = null try { addresses = geoCoder.getFromLocation(location.latitude, location.longitude, 1) } catch (ioException: Exception) { Log.e("", "Error in getting address for the location") } if (addresses == null || addresses.isEmpty()) { msg = "No address found for the location" sendResultsToReceiver(1, msg) } else { val address = addresses[0] val addressDetails = """ ${address.featureName} ${address.thoroughfare} Locality: ${address.locality} County: ${address.subAdminArea} State: ${address.adminArea} Country: ${address.countryName} Postal Code: ${address.postalCode} """.trimIndent() sendResultsToReceiver(2, addressDetails) } } private fun sendResultsToReceiver(resultCode: Int, message: String) { val bundle = Bundle() bundle.putString("address_result", message) addressResultReceiver!!.send(resultCode, bundle) } companion object { private const val IDENTIFIER = "GetAddressIntentService" } }
步骤 5 − 将以下代码添加到 androidManifest.xml 中
<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.example.q11"> <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" /> <uses-permission android:name="android.permission.INTERNET" /> <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>
让我们尝试运行您的应用程序。我假设您已将您的实际 Android 移动设备连接到您的计算机。要从 Android Studio 运行应用程序,请打开您的项目活动文件之一,然后单击工具栏中的运行图标 。选择您的移动设备作为选项,然后检查您的移动设备,它将显示您的默认屏幕。
点击 这里 下载项目代码。
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