Question

我想获取手机在Kotlin上的当前位置。

这是我的主要代码（摘自https://androidteachers.com/kotlin-for-android/get-location-in-android-with-kotlin）：

package com.anta40.app.locationtest;

import android.Manifest
import android.content.Context
import android.content.DialogInterface
import android.content.Intent
import android.content.pm.PackageManager
import android.location.Location
import android.location.LocationManager
import android.support.v7.app.AppCompatActivity
import android.os.Bundle
import android.provider.Settings
import android.support.v4.app.ActivityCompat
import android.support.v7.app.AlertDialog
import android.widget.Toast
import com.google.android.gms.common.ConnectionResult
import com.google.android.gms.common.api.GoogleApiClient
import com.google.android.gms.location.FusedLocationProviderClient
import com.google.android.gms.location.LocationRequest
import com.google.android.gms.location.LocationServices
import com.google.android.gms.tasks.OnSuccessListener
import kotlinx.android.synthetic.main.activity_main.*

class MainActivity : AppCompatActivity(), GoogleApiClient.ConnectionCallbacks, GoogleApiClient.OnConnectionFailedListener,
    com.google.android.gms.location.LocationListener {

    private val TAG = "MainActivity"
    private lateinit var mGoogleApiClient: GoogleApiClient
    private var mLocationManager: LocationManager? = null
    lateinit var mLocation: Location
    private var mLocationRequest: LocationRequest? = null
    private val listener: com.google.android.gms.location.LocationListener? = null
    private val UPDATE_INTERVAL = (2 * 1000).toLong()  /* 10 secs */
    private val FASTEST_INTERVAL: Long = 2000 /* 2 sec */

    lateinit var locationManager: LocationManager

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

        mGoogleApiClient = GoogleApiClient.Builder(this)
            .addConnectionCallbacks(this)
            .addOnConnectionFailedListener(this)
            .addApi(LocationServices.API)
            .build()

        mLocationManager = this.getSystemService(Context.LOCATION_SERVICE) as LocationManager

        checkLocation()
    }

    override fun onStart() {
        super.onStart()
        if (mGoogleApiClient != null) {
            mGoogleApiClient.connect();
        }
    }

    override fun onStop() {
        super.onStop()
        if (mGoogleApiClient.isConnected()) {
            mGoogleApiClient.disconnect();
        }
    }

    override fun onConnected(p0: Bundle?) {
        if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {

            return;
        }

        startLocationUpdates();

        var fusedLocationProviderClient :
                FusedLocationProviderClient = LocationServices.getFusedLocationProviderClient(this);
        fusedLocationProviderClient .getLastLocation()
            .addOnSuccessListener(this, OnSuccessListener<Location> { location ->
                // Got last known location. In some rare situations this can be null.
                if (location != null) {
                    // Logic to handle location object
                    mLocation = location;
                    txt_latitude.setText("" + mLocation.latitude)
                    txt_longitude.setText("" + mLocation.longitude)
                    Toast.makeText(
                        applicationContext, "Position: (" + mLocation.latitude.toString() + "," +
                                mLocation.longitude.toString(),
                        Toast.LENGTH_SHORT
                    ).show()
                }
            })
    }

    override fun onConnectionSuspended(p0: Int) {
        mGoogleApiClient.connect();
        Toast.makeText(applicationContext, "Connection suspended...", Toast.LENGTH_SHORT).show()
    }

    override fun onConnectionFailed(p0: ConnectionResult) {
        Toast.makeText(applicationContext, "Connection error: "+p0.errorMessage, Toast.LENGTH_SHORT).show()
    }

    override fun onLocationChanged(p0: Location?) {
        if (p0 != null) {
            Toast.makeText(
                applicationContext, "Position: (" + p0.latitude.toString() + "," + p0.longitude.toString(),
                Toast.LENGTH_SHORT
            ).show()

            txt_latitude.setText("" + mLocation.latitude)
            txt_longitude.setText("" + mLocation.longitude)
        }
    }

    private fun checkLocation(): Boolean {
        if(!isLocationEnabled())
            showAlert();
        return isLocationEnabled();
    }

    private fun isLocationEnabled(): Boolean {
        locationManager = getSystemService(Context.LOCATION_SERVICE) as LocationManager
        return locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER) || locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER)
    }

    private fun showAlert() {
        val dialog = AlertDialog.Builder(this)
        dialog.setTitle("Enable Location")
            .setMessage("Your Locations Settings is set to 'Off'.\nPlease Enable Location to " + "use this app")
            .setPositiveButton("Location Settings", DialogInterface.OnClickListener { paramDialogInterface, paramInt ->
                val myIntent = Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS)
                startActivity(myIntent)
            })
            .setNegativeButton("Cancel", DialogInterface.OnClickListener { paramDialogInterface, paramInt -> })
        dialog.show()
    }

    protected fun startLocationUpdates() {

        // Create the location request
        mLocationRequest = LocationRequest.create()
            .setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY)
            .setInterval(UPDATE_INTERVAL)
            .setFastestInterval(FASTEST_INTERVAL);
        // Request location updates
        if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
            return;
        }
        LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient,
            mLocationRequest, this);
    }

}

我在运行Android 8（无SIM卡，仅WiFi）的无根Android手机上运行代码。位置访问已启用。但是，该应用程序不会显示位置。调试未显示任何特定错误。

这是怎么了？

Answer 1

在Android SDK 6.0之后，位置信息需要运行时权限。在您发送的代码中看不到它。（https://androidteachers.com/kotlin-for-android/get-location-in-android-with-kotlin）

在这种情况下，您应该获得运行时权限

if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) { return; }

您可以在这里品尝；（https://developer.android.com/training/permissions/requesting）

或

您可以授予设备应用程序设置权限。（仅测试用法）

如何在Kotlin上检索当前位置（经度和纬度）？

1 个答案: