问题
I'm working on FusedLocationProvider Api to get continuous location updates using sample code in this link. When i rotate device if location updates are not on it runs fine but if location updates are open on each rotation Activity leaks with 1 mLocationCallback object and 2 mListener objects. Setting mLocationCallback null onPause() prevents it from leaking but i need to instantiate new mLocationCallback onResume() and mListener, these are probably mFusedLocationClient, and mSettingsClient client objects since they take Activity as parameter, still leak.
public class MainActivity extends AppCompatActivity {
private static final String TAG = MainActivity.class.getSimpleName();
/**
* Code used in requesting runtime permissions.
*/
private static final int REQUEST_PERMISSIONS_REQUEST_CODE = 34;
/**
* Constant used in the location settings dialog.
*/
private static final int REQUEST_CHECK_SETTINGS = 0x1;
/**
* The desired interval for location updates. Inexact. Updates may be more or less frequent.
*/
private static final long UPDATE_INTERVAL_IN_MILLISECONDS = 10000;
/**
* The fastest rate for active location updates. Exact. Updates will never be more frequent
* than this value.
*/
private static final long FASTEST_UPDATE_INTERVAL_IN_MILLISECONDS =
UPDATE_INTERVAL_IN_MILLISECONDS / 2;
// Keys for storing activity state in the Bundle.
private final static String KEY_REQUESTING_LOCATION_UPDATES = "requesting-location-updates";
private final static String KEY_LOCATION = "location";
private final static String KEY_LAST_UPDATED_TIME_STRING = "last-updated-time-string";
/**
* Provides access to the Fused Location Provider API.
*/
private FusedLocationProviderClient mFusedLocationClient;
/**
* Provides access to the Location Settings API.
*/
private SettingsClient mSettingsClient;
/**
* Stores parameters for requests to the FusedLocationProviderApi.
*/
private LocationRequest mLocationRequest;
/**
* Stores the types of location services the client is interested in using. Used for checking
* settings to determine if the device has optimal location settings.
*/
private LocationSettingsRequest mLocationSettingsRequest;
/**
* Callback for Location events.
*/
private LocationCallback mLocationCallback;
/**
* Represents a geographical location.
*/
private Location mCurrentLocation;
// UI Widgets.
private Button mStartUpdatesButton;
private Button mStopUpdatesButton;
private TextView mLastUpdateTimeTextView;
private TextView mLatitudeTextView;
private TextView mLongitudeTextView;
// Labels.
private String mLatitudeLabel;
private String mLongitudeLabel;
private String mLastUpdateTimeLabel;
/**
* Tracks the status of the location updates request. Value changes when the user presses the
* Start Updates and Stop Updates buttons.
*/
private Boolean mRequestingLocationUpdates;
/**
* Time when the location was updated represented as a String.
*/
private String mLastUpdateTime;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main_activity);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
// Locate the UI widgets.
mStartUpdatesButton = (Button) findViewById(R.id.start_updates_button);
mStopUpdatesButton = (Button) findViewById(R.id.stop_updates_button);
mLatitudeTextView = (TextView) findViewById(R.id.latitude_text);
mLongitudeTextView = (TextView) findViewById(R.id.longitude_text);
mLastUpdateTimeTextView = (TextView) findViewById(R.id.last_update_time_text);
// Set labels.
mLatitudeLabel = getResources().getString(R.string.latitude_label);
mLongitudeLabel = getResources().getString(R.string.longitude_label);
mLastUpdateTimeLabel = getResources().getString(R.string.last_update_time_label);
mRequestingLocationUpdates = false;
mLastUpdateTime = "";
// Update values using data stored in the Bundle.
updateValuesFromBundle(savedInstanceState);
mFusedLocationClient = LocationServices.getFusedLocationProviderClient(this);
mSettingsClient = LocationServices.getSettingsClient(this);
// Kick off the process of building the LocationCallback, LocationRequest, and
// LocationSettingsRequest objects.
createLocationCallback();
createLocationRequest();
buildLocationSettingsRequest();
}
/**
* Updates fields based on data stored in the bundle.
*
* @param savedInstanceState The activity state saved in the Bundle.
*/
private void updateValuesFromBundle(Bundle savedInstanceState) {
if (savedInstanceState != null) {
// Update the value of mRequestingLocationUpdates from the Bundle, and make sure that
// the Start Updates and Stop Updates buttons are correctly enabled or disabled.
if (savedInstanceState.keySet().contains(KEY_REQUESTING_LOCATION_UPDATES)) {
mRequestingLocationUpdates = savedInstanceState.getBoolean(
KEY_REQUESTING_LOCATION_UPDATES);
}
// Update the value of mCurrentLocation from the Bundle and update the UI to show the
// correct latitude and longitude.
if (savedInstanceState.keySet().contains(KEY_LOCATION)) {
// Since KEY_LOCATION was found in the Bundle, we can be sure that mCurrentLocation
// is not null.
mCurrentLocation = savedInstanceState.getParcelable(KEY_LOCATION);
}
// Update the value of mLastUpdateTime from the Bundle and update the UI.
if (savedInstanceState.keySet().contains(KEY_LAST_UPDATED_TIME_STRING)) {
mLastUpdateTime = savedInstanceState.getString(KEY_LAST_UPDATED_TIME_STRING);
}
updateUI();
}
}
/**
* Sets up the location request. Android has two location request settings:
* {@code ACCESS_COARSE_LOCATION} and {@code ACCESS_FINE_LOCATION}. These settings control
* the accuracy of the current location. This sample uses ACCESS_FINE_LOCATION, as defined in
* the AndroidManifest.xml.
* <p/>
* When the ACCESS_FINE_LOCATION setting is specified, combined with a fast update
* interval (5 seconds), the Fused Location Provider API returns location updates that are
* accurate to within a few feet.
* <p/>
* These settings are appropriate for mapping applications that show real-time location
* updates.
*/
private void createLocationRequest() {
mLocationRequest = new LocationRequest();
// Sets the desired interval for active location updates. This interval is
// inexact. You may not receive updates at all if no location sources are available, or
// you may receive them slower than requested. You may also receive updates faster than
// requested if other applications are requesting location at a faster interval.
mLocationRequest.setInterval(UPDATE_INTERVAL_IN_MILLISECONDS);
// Sets the fastest rate for active location updates. This interval is exact, and your
// application will never receive updates faster than this value.
mLocationRequest.setFastestInterval(FASTEST_UPDATE_INTERVAL_IN_MILLISECONDS);
mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
}
/**
* Creates a callback for receiving location events.
*/
private void createLocationCallback() {
mLocationCallback = new LocationCallback() {
@Override
public void onLocationResult(LocationResult locationResult) {
super.onLocationResult(locationResult);
mCurrentLocation = locationResult.getLastLocation();
mLastUpdateTime = DateFormat.getTimeInstance().format(new Date());
updateLocationUI();
}
};
}
/**
* Uses a {@link com.google.android.gms.location.LocationSettingsRequest.Builder} to build
* a {@link com.google.android.gms.location.LocationSettingsRequest} that is used for checking
* if a device has the needed location settings.
*/
private void buildLocationSettingsRequest() {
LocationSettingsRequest.Builder builder = new LocationSettingsRequest.Builder();
builder.addLocationRequest(mLocationRequest);
mLocationSettingsRequest = builder.build();
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
switch (requestCode) {
// Check for the integer request code originally supplied to startResolutionForResult().
case REQUEST_CHECK_SETTINGS:
switch (resultCode) {
case Activity.RESULT_OK:
Log.i(TAG, "User agreed to make required location settings changes.");
// Nothing to do. startLocationupdates() gets called in onResume again.
break;
case Activity.RESULT_CANCELED:
Log.i(TAG, "User chose not to make required location settings changes.");
mRequestingLocationUpdates = false;
updateUI();
break;
}
break;
}
}
/**
* Handles the Start Updates button and requests start of location updates. Does nothing if
* updates have already been requested.
*/
public void startUpdatesButtonHandler(View view) {
if (!mRequestingLocationUpdates) {
mRequestingLocationUpdates = true;
setButtonsEnabledState();
startLocationUpdates();
}
}
/**
* Handles the Stop Updates button, and requests removal of location updates.
*/
public void stopUpdatesButtonHandler(View view) {
// It is a good practice to remove location requests when the activity is in a paused or
// stopped state. Doing so helps battery performance and is especially
// recommended in applications that request frequent location updates.
stopLocationUpdates();
}
/**
* Requests location updates from the FusedLocationApi. Note: we don't call this unless location
* runtime permission has been granted.
*/
private void startLocationUpdates() {
// Begin by checking if the device has the necessary location settings.
mSettingsClient.checkLocationSettings(mLocationSettingsRequest)
.addOnSuccessListener(this, new OnSuccessListener<LocationSettingsResponse>() {
@Override
public void onSuccess(LocationSettingsResponse locationSettingsResponse) {
Log.i(TAG, "All location settings are satisfied.");
//noinspection MissingPermission
mFusedLocationClient.requestLocationUpdates(mLocationRequest,
mLocationCallback, Looper.myLooper());
updateUI();
}
})
.addOnFailureListener(this, new OnFailureListener() {
@Override
public void onFailure(@NonNull Exception e) {
int statusCode = ((ApiException) e).getStatusCode();
switch (statusCode) {
case LocationSettingsStatusCodes.RESOLUTION_REQUIRED:
Log.i(TAG, "Location settings are not satisfied. Attempting to upgrade " +
"location settings ");
try {
// Show the dialog by calling startResolutionForResult(), and check the
// result in onActivityResult().
ResolvableApiException rae = (ResolvableApiException) e;
rae.startResolutionForResult(MainActivity.this, REQUEST_CHECK_SETTINGS);
} catch (IntentSender.SendIntentException sie) {
Log.i(TAG, "PendingIntent unable to execute request.");
}
break;
case LocationSettingsStatusCodes.SETTINGS_CHANGE_UNAVAILABLE:
String errorMessage = "Location settings are inadequate, and cannot be " +
"fixed here. Fix in Settings.";
Log.e(TAG, errorMessage);
Toast.makeText(MainActivity.this, errorMessage, Toast.LENGTH_LONG).show();
mRequestingLocationUpdates = false;
}
updateUI();
}
});
}
/**
* Updates all UI fields.
*/
private void updateUI() {
setButtonsEnabledState();
updateLocationUI();
}
/**
* Disables both buttons when functionality is disabled due to insuffucient location settings.
* Otherwise ensures that only one button is enabled at any time. The Start Updates button is
* enabled if the user is not requesting location updates. The Stop Updates button is enabled
* if the user is requesting location updates.
*/
private void setButtonsEnabledState() {
if (mRequestingLocationUpdates) {
mStartUpdatesButton.setEnabled(false);
mStopUpdatesButton.setEnabled(true);
} else {
mStartUpdatesButton.setEnabled(true);
mStopUpdatesButton.setEnabled(false);
}
}
/**
* Sets the value of the UI fields for the location latitude, longitude and last update time.
*/
private void updateLocationUI() {
if (mCurrentLocation != null) {
mLatitudeTextView.setText(String.format(Locale.ENGLISH, "%s: %f", mLatitudeLabel,
mCurrentLocation.getLatitude()));
mLongitudeTextView.setText(String.format(Locale.ENGLISH, "%s: %f", mLongitudeLabel,
mCurrentLocation.getLongitude()));
mLastUpdateTimeTextView.setText(String.format(Locale.ENGLISH, "%s: %s",
mLastUpdateTimeLabel, mLastUpdateTime));
}
}
/**
* Removes location updates from the FusedLocationApi.
*/
private void stopLocationUpdates() {
if (!mRequestingLocationUpdates) {
Log.d(TAG, "stopLocationUpdates: updates never requested, no-op.");
return;
}
// It is a good practice to remove location requests when the activity is in a paused or
// stopped state. Doing so helps battery performance and is especially
// recommended in applications that request frequent location updates.
mFusedLocationClient.removeLocationUpdates(mLocationCallback)
.addOnCompleteListener(this, new OnCompleteListener<Void>() {
@Override
public void onComplete(@NonNull Task<Void> task) {
mRequestingLocationUpdates = false;
setButtonsEnabledState();
}
});
}
@Override
public void onResume() {
super.onResume();
// Within {@code onPause()}, we remove location updates. Here, we resume receiving
// location updates if the user has requested them.
if (mRequestingLocationUpdates && checkPermissions()) {
startLocationUpdates();
} else if (!checkPermissions()) {
requestPermissions();
}
updateUI();
}
@Override
protected void onPause() {
super.onPause();
// Remove location updates to save battery.
stopLocationUpdates();
}
/**
* Stores activity data in the Bundle.
*/
public void onSaveInstanceState(Bundle savedInstanceState) {
savedInstanceState.putBoolean(KEY_REQUESTING_LOCATION_UPDATES, mRequestingLocationUpdates);
savedInstanceState.putParcelable(KEY_LOCATION, mCurrentLocation);
savedInstanceState.putString(KEY_LAST_UPDATED_TIME_STRING, mLastUpdateTime);
super.onSaveInstanceState(savedInstanceState);
}
/**
* Shows a {@link Snackbar}.
*
* @param mainTextStringId The id for the string resource for the Snackbar text.
* @param actionStringId The text of the action item.
* @param listener The listener associated with the Snackbar action.
*/
private void showSnackbar(final int mainTextStringId, final int actionStringId,
View.OnClickListener listener) {
Snackbar.make(
findViewById(android.R.id.content),
getString(mainTextStringId),
Snackbar.LENGTH_INDEFINITE)
.setAction(getString(actionStringId), listener).show();
}
/**
* Return the current state of the permissions needed.
*/
private boolean checkPermissions() {
int permissionState = ActivityCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_FINE_LOCATION);
return permissionState == PackageManager.PERMISSION_GRANTED;
}
private void requestPermissions() {
boolean shouldProvideRationale =
ActivityCompat.shouldShowRequestPermissionRationale(this,
Manifest.permission.ACCESS_FINE_LOCATION);
// Provide an additional rationale to the user. This would happen if the user denied the
// request previously, but didn't check the "Don't ask again" checkbox.
if (shouldProvideRationale) {
Log.i(TAG, "Displaying permission rationale to provide additional context.");
showSnackbar(R.string.permission_rationale,
android.R.string.ok, new View.OnClickListener() {
@Override
public void onClick(View view) {
// Request permission
ActivityCompat.requestPermissions(MainActivity.this,
new String[]{Manifest.permission.ACCESS_FINE_LOCATION},
REQUEST_PERMISSIONS_REQUEST_CODE);
}
});
} else {
Log.i(TAG, "Requesting permission");
// Request permission. It's possible this can be auto answered if device policy
// sets the permission in a given state or the user denied the permission
// previously and checked "Never ask again".
ActivityCompat.requestPermissions(MainActivity.this,
new String[]{Manifest.permission.ACCESS_FINE_LOCATION},
REQUEST_PERMISSIONS_REQUEST_CODE);
}
}
/**
* Callback received when a permissions request has been completed.
*/
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions,
@NonNull int[] grantResults) {
Log.i(TAG, "onRequestPermissionResult");
if (requestCode == REQUEST_PERMISSIONS_REQUEST_CODE) {
if (grantResults.length <= 0) {
// If user interaction was interrupted, the permission request is cancelled and you
// receive empty arrays.
Log.i(TAG, "User interaction was cancelled.");
} else if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {
if (mRequestingLocationUpdates) {
Log.i(TAG, "Permission granted, updates requested, starting location updates");
startLocationUpdates();
}
} else {
// Permission denied.
// Notify the user via a SnackBar that they have rejected a core permission for the
// app, which makes the Activity useless. In a real app, core permissions would
// typically be best requested during a welcome-screen flow.
// Additionally, it is important to remember that a permission might have been
// rejected without asking the user for permission (device policy or "Never ask
// again" prompts). Therefore, a user interface affordance is typically implemented
// when permissions are denied. Otherwise, your app could appear unresponsive to
// touches or interactions which have required permissions.
showSnackbar(R.string.permission_denied_explanation,
R.string.settings, new View.OnClickListener() {
@Override
public void onClick(View view) {
// Build intent that displays the App settings screen.
Intent intent = new Intent();
intent.setAction(
Settings.ACTION_APPLICATION_DETAILS_SETTINGS);
Uri uri = Uri.fromParts("package",
BuildConfig.APPLICATION_ID, null);
intent.setData(uri);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);
}
});
}
}
}
}
What should be done to prevent leak if possible without creating the objects on each rotation?
I also add image of .hprof file, as you can see it has 2 leaked Activities and total 5 instance because i rotated 2 times without starting location updates and other 2 while location updates are on..
来源：https://stackoverflow.com/questions/46795577/fusedlocationprovider-sample-code-leaks-activity