android - 向 requestLocationUpdates intentService 发送额外信息会中断位置更新

Question

我在使用传递给 LocationServices.FusedLocationApi.requestLocationUpdates(GoogleApiClient client, LocationRequest request, PendingIntent callbackIntent) 的 PendingIntent 发送额外字符串时遇到问题。

看来我在 Intent 上添加的额外用户名正在破坏 requestLocationUpdates 试图移交给我的 IntentService 的位置> 作为 intent.getParcelableExtra(FusedLocationProviderApi.KEY_LOCATION_CHANGED) 返回 null。

编辑

我已经尝试制作一个实现 Parcelable 的 User 类并将其作为额外的:

mRequestLocationUpdatesIntent.putExtra("username", new User(username));

而且我还尝试将 Parcelable User 放入 Bundle 中，正如此错误报告 https://code.google.com/p/android/issues/detail?id=81812 中评论所建议的那样:

Bundle userBundle = new Bundle();
userBundle.putParcelable("user", new User(username));
mRequestLocationUpdatesIntent.putExtra("user", userBundle);

在我的服务中:

Bundle userBundle = intent.getBundleExtra("user");
User user = userBundle.getParcelable("user");
String username = user.getUsername();

然而，这两种方法都没有任何区别。每当我在我的 Intent 上添加任何额外内容时，位置永远不会在更新发生时添加到 Intent 中。

我设置这个 IntentService 来处理位置更新:

public class LocationUpdateService extends IntentService {

    private final String TAG = "LocationUpdateService";

    public LocationUpdateService() {
        super("LocationUpdateService");
    }


    @Override
    protected void onHandleIntent(Intent intent) {

        Log.d(TAG, "onHandleIntent");

        Bundle extras = intent.getExtras();
        Log.d(TAG, "keys found inside intent: " + TextUtils.join(", ", extras.keySet()));

        String username = intent.getStringExtra("username");

        if (username != null) {
            Log.d(TAG, "username: " + username);
        } else {
            Log.d(TAG, "username: null");
        }

        if (!intent.hasExtra(FusedLocationProviderApi.KEY_LOCATION_CHANGED)) {
            Log.d(TAG, "intent does not have location :(");
        }

        Location location = intent.getParcelableExtra(FusedLocationProviderApi.KEY_LOCATION_CHANGED);

        if (location == null) {
            Log.d(TAG, "location == null :(");
        }

        Log.d(TAG, "latitude " + String.valueOf(location.getLatitude()));
        Log.d(TAG, "longitude " + String.valueOf(location.getLongitude()));

        ...

    }


}

当用户点击一个按钮时，startLocationUpdates 在我的主要 Activity 中被调用:

主要 Activity 类:

...

Boolean mLocationUpdatesEnabled = false;

protected void createLocationRequest() {
    mLocationRequest = new LocationRequest();
    mLocationRequest.setInterval(LOCATION_UPDATE_INTERVAL);
    mLocationRequest.setFastestInterval(LOCATION_UPDATE_FASTEST_INTERVAL);
    mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
}

protected void startLocationUpdates() {

    Log.d(TAG, "startng location updates...");

    mLocationUpdatesEnabled = true;

    if (mLocationRequest == null) {
        createLocationRequest();
    }

    // create the Intent to use WebViewActivity to handle results
    Intent mRequestLocationUpdatesIntent = new Intent(this, LocationUpdateService.class);

    // create a PendingIntent
    mRequestLocationUpdatesPendingIntent = PendingIntent.getService(getApplicationContext(), 0,
            mRequestLocationUpdatesIntent,
            PendingIntent.FLAG_CANCEL_CURRENT);

    // request location updates
    LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient,
            mLocationRequest,
            mRequestLocationUpdatesPendingIntent);

    Log.d(TAG, "location updates started");
}

protected void stopLocationUpdates() {

    Log.d(TAG, "stopping location updates...");

    mLocationUpdatesEnabled = false;

    LocationServices.FusedLocationApi.removeLocationUpdates(
            mGoogleApiClient,
            mRequestLocationUpdatesPendingIntent);

    Log.d(TAG, "location updates stopped");
}

这一切都很好；当用户按下按钮时，toggleLocationUpdates 被调用，它调用 LocationServices.FusedLocationApi.requestLocationUpdates 调用我的 LocationUpdateService 我可以得到位置。

当我尝试使用 Intent.putExtra(String, String) 将字符串额外添加到我的 Intent 时，问题来了:

主要 Activity 类:

...
protected void startLocationUpdates(String username) {
    ....

    // create the Intent to use WebViewActivity to handle results
    Intent mRequestLocationUpdatesIntent = new Intent(this, LocationUpdateService.class);

    //////////////////////////////////////////////////////////////////
    //
    //  When I put this extra, IntentService sees my username extra
    //  but the parcelableExtra `location` == null :(
    // 
    //////////////////////////////////////////////////////////////////

    mRequestLocationUpdatesIntent.putExtra("username", username);
    ...
}
...

编辑 我将下一句作为陈述而不是问题开始:“我正在使用...”

我是否使用正确的方法将一些额外数据发送到此位置更新处理 IntentService 或者是否有更理智的方法来解决这个问题？

这是一个错误还是仅仅是糟糕的文档？

Answer 1

将 IntentService 与 FusedLocationProviderAPI 结合使用会出现问题。来自标题为接收位置更新的开发者文档:

Depending on the form of the request, the fused location provider either invokes the LocationListener.onLocationChanged() callback method and passes it a Location object, or issues a PendingIntent that contains the location in its extended data. The accuracy and frequency of the updates are affected by the location permissions you've requested and the options you set in the location request object

此外，PendingIntent 用于扩展另一段代码(Google Play 服务中的 FusedLocationProviderAPI)的权限，以在您的 apk 中执行它们的代码。 IntentService 用于启动在您的 apk 范围内定义的服务。

因此，该方法需要实现用于前台更新的 LocationListener，或者用于后台更新的 PendingIntent 以及广播接收器。

这是一些用于从 PendingIntent 请求位置更新以及额外值的方法的工作示例。

注意:LocalStorage.java 是一个用于存储局部变量的实用类，它不是 Android API 的一部分

GPS 绘图仪

/**
 * Private helper method to initialize the Google Api Client with the
 * LocationServices Api and Build it for use.
 */
private void initializeGoogleApiClient() {
    mGoogleApiClient = new GoogleApiClient.Builder(mContext)
            .addConnectionCallbacks(this)
            .addOnConnectionFailedListener(this)
            .addApi(LocationServices.API)
            .build();

}

/**
 * Private helper method to determine whether or not GooglePlayServices
 * are installed on the local system.
 *
 * @return services are installed.
 */
private boolean googlePlayServicesInstalled() {
    int result = GooglePlayServicesUtil.isGooglePlayServicesAvailable(mContext);
    return result == ConnectionResult.SUCCESS;
}

/**
 * Private method to build the Api Client for use with the LocationServices API.
 */
private synchronized void buildApiClient() {
    Log.w(TAG, "Building Google Api Client...");
    initializeGoogleApiClient();
}

/**
 * Private method used to connect the ApiClient to the Api hosted by Google for
 * Accessing Locations.
 */
private void connectClient() {
    mGoogleApiClient.connect();
}

 /**
 * User passes in a requested interval polling time in seconds as an
 * integer.
 *
 * @param theAccount is a reference to the parent activity used for updating views.
 */
public void beginManagedLocationRequests(MyAccount theAccount) {
    if (mAccount == null)
        mAccount = theAccount;

    startBackgroundUpdates();

}

/**
 * Public method to end the managed Location Requests.
 */
public void endManagedLocationRequests() {
        endBackgroundUpdates();

}

/**
 * This method handles the switch in polling rates by stopping and then starting once more the
 * background udpates, which in turn sets the interval in another method in the call stack.
 * @param theInterval the desired interval polling rate
 */
public void changeRequestIntervals(int theInterval) {
    mIntentInterval = theInterval;
    if (LocalStorage.getRequestingBackgroundStatus(mContext)) {
        endBackgroundUpdates();
        startBackgroundUpdates();
    }



}

/**
 * Private helper method to build an Intent that will be couple with a pending intent uses
 * for issuing background Location requests.
 *
 * @return theIntent
 */
private Intent buildBackgroundRequestIntent() {
    Intent intent = new Intent(mContext, BackgroundLocationReceiver.class);
    intent.setAction(BACKGROUND_ACTION);
    intent.putExtra(User.USER_ID, mUserID);
    return intent;
}

/**
 * Private helper method used to generate a PendingIntent for use when the User requests background service
 * within the FusedLocationApi until the Interval is changed.
 *
 * @return pendingIntent
 */
private PendingIntent buildRequestPendingIntent(Intent theIntent) {
    Log.w(TAG, "building pending intent");
    return PendingIntent.getBroadcast(mContext, 0, theIntent, 0);
}


/**
 * Private method to start the Location Updates using the FusedLocation API in the background.
 */
private void startBackgroundUpdates() {
    Log.w(TAG, "Starting background updates");
    if (googlePlayServicesInstalled()) {
        LocalStorage.putBackgroundRequestStatus(true, mContext);
        LocalStorage.putLocationRequestStatus(true, mContext);
        registerAlarmManager();
        LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, buildLocationRequest(), buildRequestPendingIntent(buildBackgroundRequestIntent()));
    }
}


/**
 * Private method to end background updates.
 */
private void endBackgroundUpdates() {
    Log.w(TAG, "Ending background updates");
    LocalStorage.putBackgroundRequestStatus(false, mContext);
    LocalStorage.putLocationRequestStatus(false, mContext);
    unregisterAlarmManager();
    LocationServices.FusedLocationApi.removeLocationUpdates(mGoogleApiClient, buildRequestPendingIntent(buildBackgroundRequestIntent()));
}

BackgroundLocationReceiver

public class BackgroundLocationReceiver extends BroadcastReceiver {
private static final String TAG = "BLocRec: ";
private static final String UPLOAD_ERROR_MESSAGE = "Background Service to Upload Coordinates Failed.";
private static final String UPLOAD_MESSAGE = "Coordinate Batch Pushed to Database.";

public BackgroundLocationReceiver() {
    //Default, no-arg constructor
}

/**
 * This method handles any location updates received when the app is no longer in focus. Coordinates are
 * stored in the local database and uploaded once every hour.
 * @param context the application context
 * @param intent is the pending intent
 */
@Override
public void onReceive(Context context, Intent intent) {

    if (intent.getAction().matches(GPSPlotter.BACKGROUND_ACTION)) {
        Log.w(TAG, "BLR Received-background");
        Location location = intent.getParcelableExtra(FusedLocationProviderApi.KEY_LOCATION_CHANGED);
        storeLocation(location, context, intent.getStringExtra(User.USER_ID));

    }

编辑下面的方法构建了调用 requestLocationUpdates() 方法所必需的 LocationRequest

/**
 * Private helper method used to generate a LocationRequest which will be used to handle all location updates
 * within the FusedLocationApi until the Interval is changed.
 *
 * @return locationRequest
 */
private LocationRequest buildLocationRequest() {
    int dateConversion = 1000;
    LocationRequest locationRequest = LocationRequest.create();
    locationRequest.setInterval(mIntentInterval * dateConversion);
    locationRequest.setFastestInterval((mIntentInterval / 2) * dateConversion);
    locationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
    Log.w(TAG, "Building location request");
    return locationRequest;
}

编辑在与 Catherine 进行了长时间的讨论后，我们得出的结论是 google play 服务库 7.5 存在一个错误，即当将其他附加内容放入 Intent 时，该错误不会处理从 FusedLocationProviderAPI 传递的 Parcelable Extra Location。但是，7.0 确实提供了这种能力。她说她会提交一个错误，我们将看看 Android 团队需要多长时间才能解决