我正在开发一个 Android 应用程序，但在这方面我还是新手。
在我的应用程序中，我使用 FusedLocationApi 来获取最后知道的位置并发出位置更新请求，但我遇到了一个问题，即使在 Android Studio 模拟器和 Samsung Galaxy S5 上激活了位置和 WiFi，我也从未得到过调用 LocationListener 的 onLocationChanged()。
这是我的代码:
package com.trackit.app.locationupdatetest;
import android.content.pm.PackageManager;
import android.location.Location;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v4.app.ActivityCompat;
import android.support.v4.app.FragmentActivity;
import android.os.Bundle;
import android.support.v4.content.ContextCompat;
import android.util.Log;
import android.view.View;
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.LocationListener;
import com.google.android.gms.location.LocationRequest;
import com.google.android.gms.location.LocationServices;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.OnMapReadyCallback;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;
public class MapsActivity extends FragmentActivity implements OnMapReadyCallback, GoogleApiClient.ConnectionCallbacks, GoogleApiClient.OnConnectionFailedListener, LocationListener {
private static final String TAG = MapsActivity.class.getSimpleName();
public static final String STARTING_POSITION = "Rio de Janeiro"; //Application's default position
public static final int MY_PERMISSIONS_REQUEST_FINE_LOCATION = 1; //Fine location permission
private GoogleMap mMap;
private GoogleApiClient mGoogleApiClient;
private LocationRequest mLocationRequest;
private MapsActivity mActivity;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_maps);
(findViewById(R.id.Location)).setEnabled(false);
(findViewById(R.id.StreetView)).setEnabled(false);
// Obtain the SupportMapFragment and get notified when the map is ready to be used.
SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
.findFragmentById(R.id.map);
mapFragment.getMapAsync(this);
if (mGoogleApiClient == null)
buildGoogleAPIClient();
//Create and configure a Location Request object to used while looking for location updates
if(mLocationRequest == null)
buildLocationRequest();
mActivity = this;
}
private synchronized void buildGoogleAPIClient() {
//Configuring the Google API client before connect
mGoogleApiClient = new GoogleApiClient.Builder(this)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.addApi(LocationServices.API)
.build();
}
private synchronized void buildLocationRequest() {
mLocationRequest = LocationRequest.create()
.setInterval(10000)
.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY)
.setFastestInterval(1000)
.setSmallestDisplacement(1);
}
@Override
protected void onStart() {
super.onStart();
mGoogleApiClient.connect();
}
/**
* This method is called when the Activity is no longer visible to the user.
*/
@Override
protected void onStop() {
if(mGoogleApiClient.isConnected())
mGoogleApiClient.disconnect();
super.onStop();
}
/**
* This callback is triggered when the map is ready to be used.
*/
@Override
public void onMapReady(GoogleMap googleMap) {
mMap = googleMap;
// Add a marker in Sydney and move the camera
LatLng sydney = new LatLng(-34, 151);
mMap.addMarker(new MarkerOptions().position(sydney).title("Marker in Sydney"));
mMap.moveCamera(CameraUpdateFactory.newLatLng(sydney));
}
public void buttonPressed(View buttonPressed){
displayUserLocation();
}
@Override
public void onConnected(@Nullable Bundle bundle) {
(findViewById(R.id.Location)).setEnabled(true);
(findViewById(R.id.StreetView)).setEnabled(true);
}
@Override
public void onConnectionSuspended(int i) {
}
@Override
public void onConnectionFailed(@NonNull ConnectionResult connectionResult) {
Log.e(TAG,"onConnectionFailed:"+connectionResult.getErrorCode()+","+connectionResult.getErrorMessage());
}
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String permissions[], @NonNull
int[] grantResults) {
//Process the user permission's response
switch (requestCode) {
case MY_PERMISSIONS_REQUEST_FINE_LOCATION:
processLocationPermissionResult(grantResults);
break;
default:
}
}
public void processLocationPermissionResult(@NonNull int grantResults[]) {
// If request is cancelled, the result arrays are empty.
if (grantResults.length > 0
&& grantResults[0] == PackageManager.PERMISSION_GRANTED)
displayLocation();
else {} // permission denied, boo! Disable the functionality that depends on this permission.
}
public void displayUserLocation(){
//Verify if the app have permission to access user's location
if (ContextCompat.checkSelfPermission(this, android.Manifest.permission.
ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
if (ActivityCompat.shouldShowRequestPermissionRationale(this, android.Manifest.
permission.ACCESS_FINE_LOCATION)) {
//Asks the permission to access the user's location
Toast.makeText(this, "This app needs to access your location. " +
"Allow the app to access it?", Toast.LENGTH_LONG).show();
} else {
ActivityCompat.requestPermissions(this,
new String[]{android.Manifest.permission.ACCESS_FINE_LOCATION},
MapsActivity.MY_PERMISSIONS_REQUEST_FINE_LOCATION);
}
} else displayLocation(); //If the permission was granted
}
public void displayLocation() throws SecurityException{
Location lastLocation = LocationServices.FusedLocationApi.
getLastLocation(mGoogleApiClient);
if(lastLocation != null) {
Log.e(TAG, "!!!!!!");
LatLng position = new LatLng(lastLocation.getLatitude(), lastLocation.
getLongitude());
mMap.addMarker(new MarkerOptions().position(position).title("Marker in " +
MapsActivity.STARTING_POSITION));
mMap.moveCamera(CameraUpdateFactory.newLatLng(position));
} else{
Log.e(TAG, "??????");
LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient,
mLocationRequest, this);
}
}
@Override
public void onLocationChanged(Location location) {
if(location.getAccuracy() < 10 && location.getSpeed() < 55.55555555555556){
Log.e(TAG, "onLocationChanged() started");
LatLng position = new LatLng(location.getLatitude(), location.getLongitude());
mMap.addMarker(new MarkerOptions().position(position).title("Marker in " +
MapsActivity.STARTING_POSITION));
mMap.moveCamera(CameraUpdateFactory.newLatLng(position));
LocationServices.FusedLocationApi.removeLocationUpdates(mGoogleApiClient, this);
Log.e(TAG, "onLocationChanged() terminated");
}
/*else{
//Continue listening for a more accurate location
}*/
}
}
下面是我的 AndroidManifest.xml 和我的 gradle:
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.trackit.app.locationupdatetest">
<!--
The ACCESS_COARSE/FINE_LOCATION permissions are not required to use
Google Maps Android API v2, but you must specify either coarse or fine
location permissions for the 'MyLocation' functionality.
-->
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-feature
android:glEsVersion="0x00020000"
android:required="true"/>
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<!--
The API key for Google Maps-based APIs is defined as a string resource.
(See the file "res/values/google_maps_api.xml").
Note that the API key is linked to the encryption key used to sign the APK.
You need a different API key for each encryption key, including the release key that is used to
sign the APK for publishing.
You can define the keys for the debug and release targets in src/debug/ and src/release/.
-->
<meta-data
android:name="com.google.android.geo.API_KEY"
android:value="@string/google_maps_key" />
<activity
android:name=".MapsActivity"
android:label="@string/title_activity_maps">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
Gradle
apply plugin: 'com.android.application'
android {
compileSdkVersion 24
buildToolsVersion "24.0.1"
defaultConfig {
applicationId "com.trackit.app.locationupdatetest"
minSdkVersion 21
targetSdkVersion 24
versionCode 1
versionName "1.0"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
}
dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
testCompile 'junit:junit:4.12'
compile 'com.android.support:appcompat-v7:24.2.0'
compile 'com.google.android.gms:play-services:9.4.0'
}
这周我搜索了很多，但还没有得到有用的答案=s
这些是我搜索过的一些主题(我不想看起来像个懒惰的人，因为我不是，我只是被困住了)
onLocationChanged does not get called using fusedLocationAPI.requestLocationUpdates
Unable to get location updates
onLocationChanged not called on some devices
on locaton changed never gets called in android google client api
onLocationChanged isn't being called
有人可以指出我的错误吗？ =S
最佳答案
我会冒昧地回答这个问题...如果有帮助，那就太好了...如果没有，抱歉...
我有一个使用 FusedLocationprovider 的类似 Activity 。
我不是专家，不能说为什么你的不起作用，但我的却起作用，并且我注意到以下差异:
您的代码:
private synchronized void buildGoogleAPIClient() {
//Configuring the Google API client before connect
mGoogleApiClient = new GoogleApiClient.Builder(this)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.addApi(LocationServices.API)
.build();
}
private synchronized void buildLocationRequest() {
mLocationRequest = LocationRequest.create()
.setInterval(10000)
.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY)
.setFastestInterval(1000)
.setSmallestDisplacement(1);
}
我的代码:
protected synchronized void buildGoogleApiClient() {
this.mGoogleApiClient = new GoogleApiClient.Builder(this).
addConnectionCallbacks(this).
addOnConnectionFailedListener(this).
addApi(LocationServices.API).build();
createLocationRequest();
}
protected void createLocationRequest() {
this.mLocationRequest = new LocationRequest();
this.mLocationRequest.setInterval(UPDATE_INTERVAL_IN_MILLISECONDS);
this.mLocationRequest.setFastestInterval(FASTEST_UPDATE_INTERVAL_IN_MILLISECONDS);
this.mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
}
差异:
1)你输入:
if(mLocationRequest == null)
buildLocationRequest();
在你的 onCreate 方法中。有这个必要吗？在 onCreate() 中 mLocationRequest 不是总是为 null 吗？
2)你的方法是私有(private)的，我的方法 protected
3) 您的 createLocationrequest() 被标记为“同步”...可能因此而无法工作？
4) 您使用 setSmallestDisplacement() 方法。我看到一些帖子说此方法无法正常工作并导致 onLocationChanged() 未被调用。
5) 您使用“LocationRequest.create()”实例化 LocationRequest，而不是“new LocationRequest()”，这可能是问题所在吗？
这有帮助吗？
关于java - Android LocationListener onLocationChanged() 永远不会被调用，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/39461363/