Fragment able to start task which is not interrupted during configuration changes

Fragment able to start task which is not interrupted during configuration changes - android

Sorry for my English
This is not question. I post it because this is may be helpful for someone. My solution based on the solution which was placed here several months ago, but later its author removed it. But there were several bugs in his solution, and I tried to fix them.
My solution works fine even if you'll open another app while there is a long-executed task executed in your app, then change screen orientation in another app, and return to your app after task will be finished.
If you'll find a bug in my solution, please let me know.
Have a look:
public interface AbleToStartTask {
void startTask(int requestCode, TaskNotBeInterruptedDuringConfigurationChange task);
void startTask(int requestCode, TaskNotBeInterruptedDuringConfigurationChange task, Integer titleId);
}
public interface TaskResultReceiver {
void onTaskResult(int requestCode, int resultCode, Serializable result);
}
public abstract class TaskNotBeInterruptedDuringConfigurationChange extends AsyncTask<Void, Void, Serializable> {
private TaskFragment fragment;
final void setFragment(TaskFragment fragment) {
this.fragment = fragment;
}
#Override
protected final void onPostExecute(Serializable result) {
if (fragment != null) {
fragment.onTaskFinished(result);
}
}
}
public class TaskFragment extends android.support.v4.app.DialogFragment {
public static final Integer NO_TITLE_ID = null;
private boolean isNeedToReturnResult = false;
private boolean isResultReturned = false;
private TaskNotBeInterruptedDuringConfigurationChange task;
private int resultCode = Activity.RESULT_CANCELED;
private Serializable result = null;
private Integer titleId;
public void setTask(TaskNotBeInterruptedDuringConfigurationChange task) {
task.setFragment(this);
this.task = task;
}
public void setTitle(Integer titleId) {
this.titleId = titleId;
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setRetainInstance(true);
if (savedInstanceState == null && task != null) {
task.execute();
}
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
initDialog();
return inflater.inflate(R.layout.fragment_task, container);
}
private void initDialog() {
if (titleId == NO_TITLE_ID) {
getDialog().getWindow().requestFeature(Window.FEATURE_NO_TITLE);
getDialog().getWindow().setBackgroundDrawableResource(android.R.color.transparent);
} else {
getDialog().setTitle(titleId);
}
getDialog().setCanceledOnTouchOutside(false);
}
#Override
public void onDestroyView() {
if ((getDialog() != null) && getRetainInstance()) {
getDialog().setDismissMessage(null);
}
super.onDestroyView();
}
#Override
public void onDismiss(DialogInterface dialog) {
super.onDismiss(dialog);
if (task != null) {
task.cancel(false);
}
tryReturnResult();
}
private void tryReturnResult() {
task = null;
if (isResultReturned) {
return;
}
if (getTargetFragment() != null) {
returnResult();
}
}
private void returnResult() {
isResultReturned = true;
FragmentAbleToStartTask ableToStartTask = (FragmentAbleToStartTask) getTargetFragment();
if (ableToStartTask.isAbleToReceiveResult()) {
ableToStartTask.onResult(FragmentAbleToStartTask.TASK_FRAGMENT_TARGET, resultCode, result);
isNeedToReturnResult = false;
finishFragment();
} else {
isNeedToReturnResult = true;
}
}
private void finishFragment() {
if (isResumed()) {
dismiss();
}
}
#Override
public void onResume() {
super.onResume();
if (task == null) {
dismiss();
}
}
public void onTaskFinished(Serializable result) {
setResult(Activity.RESULT_OK, result);
tryReturnResult();
}
private void setResult(int resultCode, Serializable result) {
this.resultCode = resultCode;
this.result = result;
}
public void getResultIfItReturnedDuringPause() {
if (isNeedToReturnResult) {
returnResult();
}
}
}
public abstract class FragmentAbleToStartTask extends android.support.v4.app.Fragment
implements AbleToStartTask, TaskResultReceiver {
public static final int TASK_FRAGMENT_TARGET = 123;
protected static final String TAG_TASK_FRAGMENT = FragmentAbleToStartTask.class.getName() + "TAG_TASK_FRAGMENT";
private static final String KEY_TASK_REQUEST_CODE = "KEY_TASK_REQUEST_CODE";
private FragmentManager fragmentManager;
private int taskRequestCode;
#Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
outState.putInt(KEY_TASK_REQUEST_CODE, taskRequestCode);
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (savedInstanceState != null) {
restoreState(savedInstanceState);
}
fragmentManager = getFragmentManager();
TaskFragment taskFragment = getTaskFragment();
if (taskFragment != null) {
taskFragment.setTargetFragment(this, TASK_FRAGMENT_TARGET);
}
}
private void restoreState(Bundle savedInstanceState) {
taskRequestCode = savedInstanceState.getInt(KEY_TASK_REQUEST_CODE);
}
private TaskFragment getTaskFragment() {
return (TaskFragment) fragmentManager.findFragmentByTag(TAG_TASK_FRAGMENT);
}
public void startTask(int requestCode, TaskNotBeInterruptedDuringConfigurationChange task) {
startTask(requestCode, task, TaskFragment.NO_TITLE_ID);
}
public void startTask(int requestCode, TaskNotBeInterruptedDuringConfigurationChange task, Integer title) {
this.taskRequestCode = requestCode;
TaskFragment taskFragment = new TaskFragment();
taskFragment.setTitle(title);
taskFragment.setTask(task);
taskFragment.setTargetFragment(this, TASK_FRAGMENT_TARGET);
startFragment(taskFragment);
}
private void startFragment(TaskFragment taskFragment) {
FragmentTransaction transaction = fragmentManager.beginTransaction();
Fragment previousTaskFragment = fragmentManager.findFragmentByTag(TAG_TASK_FRAGMENT);
if (previousTaskFragment != null) {
transaction.remove(previousTaskFragment);
}
transaction.add(taskFragment, TAG_TASK_FRAGMENT);
transaction.commit();
}
public final void onResult(int requestCode, int resultCode, Serializable result) {
if ((requestCode == TASK_FRAGMENT_TARGET)) {
onTaskResult(this.taskRequestCode, resultCode, result);
}
}
public abstract void onTaskResult(int requestCode, int resultCode, Serializable result);
public boolean isAbleToReceiveResult() {
return isResumed();
}
#Override
public void onResume() {
super.onResume();
TaskFragment taskFragment = getTaskFragment();
if (taskFragment != null) {
taskFragment.getResultIfItReturnedDuringPause();
}
}
}
So each inheritor of FragmentAbleToStartTask must implement onTaskResult(requestCode, resultCode, result). In onTaskResult() - requestCode is value that was passed to startTask(requestCode, ...). And note, that this fragment is able to execute only one task at the same time.
Example of TaskNotBeInterruptedDuringConfigurationChange's subclass:
public class SomeLongTask extends TaskNotBeInterruptedDuringConfigurationChange {
private final Context context;
private final Worker worker;
public SomeLongTask (Worker worker, Context context) {
this.worker= worker;
this.context = context;
}
#Override
protected Serializable doInBackground(Void... voids) {
return (Serializable) worker.work(context);
}
}
And example of FragmentAbleToStartTask's subclass:
public class NameListFragment extends FragmentAbleToStartTask {
private static final int TASK_REQUEST_CODE_RECEIVING_NAMES = 461;
private static final String KEY_PATTERN = "KEY_PATTERN";
private static final String KEY_NAMES = "KEY_NAMES";
private List<String> names;
private ListView listView;
public static Fragment newInstance(String patternToSearchNames) {
Fragment fragment = new NameListFragment();
Bundle args = new Bundle();
args.putString(KEY_PATTERN, patternToSearchNames);
fragment.setArguments(args);
return fragment;
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View root = inflater.inflate(R.layout.example_list_fragment, null);
listView = (ListView) root.findViewById(R.id.listView);
return root;
}
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
if (savedInstanceState == null) {
startTaskReceivingNames();
} else {
restoreState(savedInstanceState);
}
}
// !!! Key Point
private void startTaskReceivingNames() {
String pattern = getArguments().getString(KEY_PATTERN);
TaskNotBeInterruptedDuringConfigurationChange task = new NamesReceiverTask(getActivity(), pattern);
startTask(TASK_REQUEST_CODE_RECEIVING_NAMES, task);
}
private void restoreState(Bundle savedInstanceState) {
names = (List<String>) savedInstanceState.getString(KEY_NAMES);
if (names != null) {
initList();
}
}
private void initList() {
setEmptyListView();
ArrayList<String> adapter = new ArrayList<String>(getActivity(), android.R.layout.simple_list_item_1, names);
listView.setAdapter(adapter);
}
private void setEmptyListView() {
View emptyListView = getView().findViewById(R.id.emptyListView);
listView.setEmptyView(emptyListView);
}
#Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
outState.putSerializable(KEY_NAMES, (Serializable) names);
}
// !!! Key Point
#Override
public void onTaskResult(int requestCode, int resultCode, Serializable result) {
if (requestCode == TASK_REQUEST_CODE_RECEIVING_NAMES) {
onReceivingNamesFinished(resultCode, result);
}
}
private void onReceivingNamesFinished(int resultCode, Serializable result) {
if (resultCode != Activity.RESULT_OK) {
getActivity().finish();
return;
}
this.names = (List<String>) result;
initList();
}
}

Related

How do i start the turn by turn NavigationLauncher from another activity

I am trying to launch the NavigationLauncher.startNavigation, from another activity but am unable to do so. I have a button in the second activity which I want to use to start the navigation.
Any suggestions are welcome. Thanks
Here is my code:
/*
fabstart.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
boolean simulateRoute = false;
NavigationLauncherOptions options = NavigationLauncherOptions.builder()
.directionsRoute(route)
.shouldSimulateRoute(simulateRoute)
.build();
// Call this method with Context from within an Activity
NavigationLauncher.startNavigation(MainActivity.this, options);
}
});
*/
fabstart.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent intent = new Intent(MainActivity.this, Before_Go.class);
startActivity(intent);
// Here is where I want to go to a new activity, inside this activity have a button to
// launch the "NavigationLauncher.startNavigation"
}
});

NavigationLauncher.startnavigation() opens a new activity that handles the navigation. Therefore it does not matter from where it is called. However, wherever it is called from, the NavigationLauncher must be defined, and the options object that is passed as the second parameter has to contain the directionsRoute object.
Can you please share code of the activity from which you call it, as well as how you initialize and define the options object?

thanks for your response to my question. I am new to stakoverflow, so i hope i get this additional posting of code right.
MainActivity
public class MainActivity extends AppCompatActivity implements OnMapReadyCallback, PermissionsListener,
MapboxMap.OnMapLongClickListener, OnRouteSelectionChangeListener {
private static final int REQUEST_CODE_AUTOCOMPLETE = 1;
private static final int ONE_HUNDRED_MILLISECONDS = 100;
//private static final String DROPPED_MARKER_LAYER_ID = "DROPPED_MARKER_LAYER_ID";
//Mapbox
private MapView mapView;
private MapboxMap mapboxMap;
private LocationComponent locationComponent;
private PermissionsManager permissionsManager;
private LocationEngine locationEngine;
private long DEFAULT_INTERVAL_IN_MILLISECONDS = 1000L;
private long DEFAULT_MAX_WAIT_TIME = DEFAULT_INTERVAL_IN_MILLISECONDS * 5;
private final MainActivityLocationCallback callback = new MainActivityLocationCallback(this);
private NavigationMapRoute mapRoute;
private DirectionsRoute route;
private String symbolIconId = "symbolIconId";
private String geojsonSourceLayerId = "geojsonSourceLayerId";
private StyleCycle styleCycle = new StyleCycle();
CarmenFeature selectedCarmenFeature;
CarmenFeature feature;
Layer layer;
private static final String TAG = "DirectionsActivity";
// variables
private FloatingActionButton fablocation;
private FloatingActionButton fabstart;
private FloatingActionButton fabRemoveRoute;
private FloatingActionButton fabStyles;
private TextView search;
private TextView kmDisplay;
private TextView timeDisplay;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Mapbox.getInstance(this, getString(R.string.access_token));
setContentView(R.layout.activity_main);
mapView = findViewById(R.id.mapView);
mapView.onCreate(savedInstanceState);
mapView.getMapAsync(this);
search=findViewById(R.id.search);
kmDisplay = findViewById(R.id.kmDisplay);
timeDisplay = findViewById(R.id.timeDisplay);
fablocation=findViewById(R.id.fabLocation);
fabstart=findViewById(R.id.fabStart);
fabRemoveRoute=findViewById(R.id.fabRemoveRoute);
fabStyles=findViewById(R.id.fabStyles);
fablocation.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Location lastKnownLocation = mapboxMap.getLocationComponent().getLastKnownLocation();
// Move map camera back to current device location
mapboxMap.animateCamera(CameraUpdateFactory.newCameraPosition(
new CameraPosition.Builder()
.target(new LatLng(lastKnownLocation.getLatitude(), lastKnownLocation.getLongitude()))
.zoom(15)
.build()), 3000);
}
});
}
#Override
public boolean onMapLongClick(#NonNull LatLng point) {
vibrate();
Point destinationPoint = Point.fromLngLat(point.getLongitude(), point.getLatitude());
Point originPoint = Point.fromLngLat(locationComponent.getLastKnownLocation().getLongitude(),
locationComponent.getLastKnownLocation().getLatitude());
GeoJsonSource source = mapboxMap.getStyle().getSourceAs("destination-source-id");
if (source != null) {
source.setGeoJson(Feature.fromGeometry(destinationPoint));
} else {
// Use the map camera target's coordinates to make a reverse geocoding search
reverseGeocode(Point.fromLngLat(point.getLongitude(), point.getLatitude()));
}
getRoute(originPoint, destinationPoint);
if(destinationPoint !=originPoint) {
fabRemoveRoute.setOnClickListener(new View.OnClickListener() {
#SuppressLint("RestrictedApi")
#Override
public void onClick(View view) {
removeRouteAndMarkers();
fabstart.setVisibility(View.INVISIBLE);
fabRemoveRoute.setVisibility(View.INVISIBLE);
//fablocation.setVisibility(View.INVISIBLE);
kmDisplay.setText("");
timeDisplay.setText("");
search.setText(String.format(getString(R.string.hint_where_to)));
Location lastKnownLocation = mapboxMap.getLocationComponent().getLastKnownLocation();
// Move map camera back to current device location
mapboxMap.animateCamera(CameraUpdateFactory.newCameraPosition(
new CameraPosition.Builder()
.target(new LatLng(lastKnownLocation.getLatitude(), lastKnownLocation.getLongitude()))
.zoom(15)
.build()), 3000);
}
});
}
//imageView.setEnabled(true);
//imageView.setBackgroundResource(R.color.mapboxBlue);
return true;
}
private void getRoute(Point origin, Point destination) {
NavigationRoute.builder(this)
.accessToken(Mapbox.getAccessToken())
.origin(origin)
.destination(destination)
.voiceUnits(DirectionsCriteria.METRIC)
.alternatives(true)
.build()
.getRoute(new Callback<DirectionsResponse>() {
#SuppressLint("RestrictedApi")
#Override
public void onResponse(Call<DirectionsResponse> call, Response<DirectionsResponse> response) {
// You can get the generic HTTP info about the response
if (response.isSuccessful()
&& response.body() != null
&& !response.body().routes().isEmpty()) {
List<DirectionsRoute> routes = response.body().routes();
mapRoute.addRoutes(routes);
//routeLoading.setVisibility(View.INVISIBLE);
fabRemoveRoute.setVisibility(View.VISIBLE);
fablocation.setVisibility(View.VISIBLE);
fabstart.setVisibility(View.VISIBLE);
route = response.body().routes().get(0);
routeCalcs();
}
// Once you have the route zoom the camera out to show the route within the bounds of the device
mapboxMap.easeCamera(CameraUpdateFactory.newLatLngBounds(
new LatLngBounds.Builder()
.include(new LatLng(origin.latitude(), origin.longitude()))
.include(new LatLng(destination.latitude(), destination.longitude()))
.build(), 150), 4000);
}
#Override
public void onFailure(Call<DirectionsResponse> call, Throwable throwable) {
Log.e(TAG, "Error: " + throwable.getMessage());
}
});
}
private void removeRouteAndMarkers() {
mapRoute.removeRoute();
toggleLayer();
}
#Override
public void onNewPrimaryRouteSelected(DirectionsRoute directionsRoute) {
route = directionsRoute;
routeCalcs();
}
private void routeCalcs(){
// rounds the kilometer to zero decimals
kmDisplay.setText((int) Math.ceil(route.distance()/1000) + " km");
//Log.d(TAG1,(int) Math.ceil(currentRoute.distance()/1000) + " km");
// This converts to output of duration() in seconds to minutes and hours format
int minutes = (int) (route.duration() / 60);
long hour = TimeUnit.MINUTES.toHours(minutes);
long remainMinute = minutes - TimeUnit.HOURS.toMinutes(hour);
if (hour >= 1) {
timeDisplay.setText(String.format(getString(R.string.hours_textview),hour)
+ String.format(getString(R.string.minutes_textview),remainMinute));
} else {
timeDisplay.setText(String.format(getString(R.string.minutes_textview), remainMinute));
}
}
private void reverseGeocode(Point point) {
if (selectedCarmenFeature == null) {
try {
MapboxGeocoding client = MapboxGeocoding.builder()
.accessToken(getString(R.string.access_token))
.query(Point.fromLngLat(point.longitude(), point.latitude()))
.geocodingTypes(GeocodingCriteria.TYPE_ADDRESS)
.build();
client.enqueueCall(new Callback<GeocodingResponse>() {
#Override
public void onResponse(Call<GeocodingResponse> call, Response<GeocodingResponse> response) {
if (response.body() != null) {
List<CarmenFeature> results = response.body().features();
if (results.size() > 0) {
feature = results.get(0);
// If the geocoder returns a result, we take the first in the list and show a Toast with the place name.
mapboxMap.getStyle(new Style.OnStyleLoaded() {
#Override
public void onStyleLoaded(#NonNull Style style) {
if (style.getLayer("SYMBOL_LAYER_ID") != null) {
search.setText(feature.placeName());
}
}
});
} else {
Toast.makeText(MainActivity.this,
getString(R.string.location_picker_dropped_marker_snippet_no_results), Toast.LENGTH_SHORT).show();
}
}
}
#Override
public void onFailure(Call<GeocodingResponse> call, Throwable throwable) {
Timber.e("Geocoding Failure: %s", throwable.getMessage());
}
});
} catch (ServicesException servicesException) {
Timber.e("Error geocoding: %s", servicesException.toString());
servicesException.printStackTrace();
}
}
}
#Override
public void onMapReady(#NonNull MapboxMap mapboxMap) {
this.mapboxMap = mapboxMap;
mapboxMap.setStyle(Style.MAPBOX_STREETS, new Style.OnStyleLoaded() {
#Override
public void onStyleLoaded(#NonNull Style style){
mapRoute = new NavigationMapRoute(null, mapView, mapboxMap);
mapRoute.setOnRouteSelectionChangeListener(MainActivity.this::onNewPrimaryRouteSelected);
mapboxMap.addOnMapLongClickListener(MainActivity.this);
initializeLocationComponent(style);
// Add the symbol layer icon to map for future use
style.addImage(symbolIconId, BitmapFactory.decodeResource(
MainActivity.this.getResources(), R.drawable.mapbox_marker_icon_default));
// Create an empty GeoJSON source using the empty feature collection
setUpSource(style);
// Set up a new symbol layer for displaying the searched location's feature coordinates
setupLayer(style);
fabStyles.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
if (mapboxMap != null) {
mapboxMap.setStyle(styleCycle.getNextStyle());
}
}
});
initSearchFab();
}
});
// This is the code in the docs, but this launches the turn by turn navigation inside this activity
// and this is not what I need
/* fabstart.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
boolean simulateRoute = false;
NavigationLauncherOptions options = NavigationLauncherOptions.builder()
.directionsRoute(route)
.shouldSimulateRoute(simulateRoute)
.build();
// Call this method with Context from within an Activity
NavigationLauncher.startNavigation(MainActivity.this, options);
}
});*/
fabstart.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent intent = new Intent(MainActivity.this, Before_Go.class);
startActivity(intent);
// Here is where I want to go to a new activity, inside this activity have a button to
// launch the "NavigationLauncher.startNavigation"
}
});
}
private static class StyleCycle {
private static final String[] STYLES = new String[] {
Style.MAPBOX_STREETS,
Style.OUTDOORS,
Style.LIGHT,
Style.DARK,
//Style.SATELLITE_STREETS,
Style.TRAFFIC_DAY,
Style.TRAFFIC_NIGHT
};
private int index;
private String getNextStyle() {
index++;
if (index == STYLES.length) {
index = 0;
}
return getStyle();
}
private String getStyle() {
return STYLES[index];
}
}
private void initSearchFab() {
findViewById(R.id.search).setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent intent = new PlaceAutocomplete.IntentBuilder()
.accessToken(Mapbox.getAccessToken())
.placeOptions(PlaceOptions.builder()
.backgroundColor(Color.parseColor("#EEEEEE"))
.limit(10)
//.addInjectedFeature(home)
//.addInjectedFeature(work)
.build(PlaceOptions.MODE_CARDS))
.build(MainActivity.this);
startActivityForResult(intent, REQUEST_CODE_AUTOCOMPLETE);
}
});
}
#SuppressWarnings( {"MissingPermission"})
private void initializeLocationComponent(#NonNull Style loadedMapStyle) {
// Check if permissions are enabled and if not request
if (PermissionsManager.areLocationPermissionsGranted(this)) {
locationComponent = mapboxMap.getLocationComponent();
// Set the LocationComponent activation options
LocationComponentActivationOptions locationComponentActivationOptions =
LocationComponentActivationOptions.builder(this, loadedMapStyle)
.useDefaultLocationEngine(false)
.build();
// Activate with the LocationComponentActivationOptions object
locationComponent.activateLocationComponent(locationComponentActivationOptions);
locationComponent.setLocationComponentEnabled(true);
locationComponent.setRenderMode(RenderMode.NORMAL);
locationComponent.setCameraMode(CameraMode.TRACKING);
//locationComponent.zoomWhileTracking(10d);
initLocationEngine();
} else {
permissionsManager = new PermissionsManager(this);
permissionsManager.requestLocationPermissions(this);
}
}
#Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (resultCode == Activity.RESULT_OK && requestCode == REQUEST_CODE_AUTOCOMPLETE) {
// Retrieve selected location's CarmenFeature
selectedCarmenFeature = PlaceAutocomplete.getPlace(data);
search.setText(selectedCarmenFeature.placeName());
// Create a new FeatureCollection and add a new Feature to it using selectedCarmenFeature above.
// Then retrieve and update the source designated for showing a selected location's symbol layer icon
if (mapboxMap != null) {
Style style = mapboxMap.getStyle();
if (style != null) {
GeoJsonSource source = style.getSourceAs(geojsonSourceLayerId);
if (source != null) {
source.setGeoJson(FeatureCollection.fromFeatures(
new Feature[] {Feature.fromJson(selectedCarmenFeature.toJson())}));
}
// Move map camera to the selected location
mapboxMap.animateCamera(CameraUpdateFactory.newCameraPosition(
new CameraPosition.Builder()
.target(new LatLng(((Point) selectedCarmenFeature.geometry()).latitude(),
((Point) selectedCarmenFeature.geometry()).longitude()))
.zoom(14)
.build()), 4000);
}
}
}
}
#SuppressLint("MissingPermission")
private void vibrate() {
Vibrator vibrator = (Vibrator) getSystemService(Context.VIBRATOR_SERVICE);
if (vibrator == null) {
return;
}
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
vibrator.vibrate(VibrationEffect.createOneShot(ONE_HUNDRED_MILLISECONDS, VibrationEffect.DEFAULT_AMPLITUDE));
} else {
vibrator.vibrate(ONE_HUNDRED_MILLISECONDS);
}
}
/**
* Set up the LocationEngine and the parameters for querying the device's location
*/
#SuppressLint("MissingPermission")
private void initLocationEngine() {
locationEngine = LocationEngineProvider.getBestLocationEngine(this);
LocationEngineRequest request = new LocationEngineRequest.Builder(DEFAULT_INTERVAL_IN_MILLISECONDS)
.setPriority(LocationEngineRequest.PRIORITY_HIGH_ACCURACY)
.setMaxWaitTime(DEFAULT_MAX_WAIT_TIME).build();
locationEngine.requestLocationUpdates(request, callback, getMainLooper());
locationEngine.getLastLocation(callback);
}
#Override
public void onExplanationNeeded(List<String> permissionsToExplain) {
Toast.makeText(this, R.string.user_location_permission_explanation, Toast.LENGTH_LONG).show();
}
#Override
public void onPermissionResult(boolean granted) {
if (granted) {
if (mapboxMap.getStyle() != null) {
initializeLocationComponent(mapboxMap.getStyle());
}
} else {
Toast.makeText(this, R.string.user_location_permission_not_granted, Toast.LENGTH_LONG).show();
finish();
}
}
#Override
public void onRequestPermissionsResult(int requestCode, #NonNull String[] permissions, #NonNull int[] grantResults) {
permissionsManager.onRequestPermissionsResult(requestCode, permissions, grantResults);
}
private static class MainActivityLocationCallback
implements LocationEngineCallback<LocationEngineResult> {
private final WeakReference<MainActivity> activityWeakReference;
MainActivityLocationCallback(MainActivity activity) {
this.activityWeakReference = new WeakReference<>(activity);
}
#Override
public void onSuccess(LocationEngineResult result) {
MainActivity activity = activityWeakReference.get();
if (activity != null) {
Location location = result.getLastLocation();
if (location == null) {
return;
}
if (activity.mapboxMap != null && result.getLastLocation() != null) {
activity.mapboxMap.getLocationComponent().forceLocationUpdate(result.getLastLocation());
}
}
}
#Override
public void onFailure(#NonNull Exception exception) {
Timber.d(exception.getLocalizedMessage());
MainActivity activity = activityWeakReference.get();
if (activity != null) {
Toast.makeText(activity, exception.getLocalizedMessage(),
Toast.LENGTH_SHORT).show();
}
}
}
/**
* Adds the GeoJSON source to the map
*/
private void setUpSource(#NonNull Style loadedMapStyle) {
loadedMapStyle.addSource(new GeoJsonSource(geojsonSourceLayerId));
}
/**
* Setup a layer with maki icons, eg. west coast city.
*/
private void setupLayer(#NonNull Style loadedMapStyle) {
loadedMapStyle.addLayer(new SymbolLayer("SYMBOL_LAYER_ID", geojsonSourceLayerId).withProperties(
iconImage(symbolIconId),
iconOffset(new Float[] {0f, -8f})
));
}
// This method will remove the destination icon
private void toggleLayer() {
mapboxMap.getStyle(new Style.OnStyleLoaded() {
#Override
public void onStyleLoaded(#NonNull Style style) {
layer = style.getLayer("SYMBOL_LAYER_ID");
if (layer != null) {
if (VISIBLE.equals(layer.getVisibility().getValue())) {
layer.setProperties(visibility(NONE));
} else {
layer.setProperties(visibility(VISIBLE));
}
}
}
});
}
// Add the mapView lifecycle to the activity's lifecycle methods
#Override
public void onResume() {
super.onResume();
mapView.onResume();
}
#Override
protected void onStart() {
super.onStart();
mapView.onStart();
if (mapRoute != null) {
mapRoute.onStart();
}
}
#Override
protected void onStop() {
super.onStop();
mapView.onStop();
if (mapRoute != null) {
mapRoute.onStop();
}
}
#Override
public void onPause() {
super.onPause();
mapView.onPause();
}
#Override
public void onLowMemory() {
super.onLowMemory();
mapView.onLowMemory();
}
#Override
protected void onDestroy() {
super.onDestroy();
mapView.onDestroy();
}
#Override
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
mapView.onSaveInstanceState(outState);
}
}
Before_Go - this is the activity where i want to click the button and launch the navigationlauncher
public class Before_Go extends AppCompatActivity {
Button btnGo;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_before__go);
btnGo=findViewById(R.id.btnGo);
btnGo.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent btnGo = new Intent(Before_Go.this, Go.class);
startActivity(btnGo);
}
});
}
}

GoActivity, this is where the navigation launcher needs to launch after the button click in the Before_Go activity
public class Go extends AppCompatActivity implements OnNavigationReadyCallback,
NavigationListener {
private NavigationView navigationView;
private DirectionsRoute route;
#Override
protected void onCreate(#Nullable Bundle savedInstanceState) {
setTheme(R.style.Theme_AppCompat_NoActionBar);
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_go);
navigationView = findViewById(R.id.navigationViewB);
navigationView.onCreate(savedInstanceState);
}
/*fabstart.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
boolean simulateRoute = false;
NavigationLauncherOptions options = NavigationLauncherOptions.builder()
.directionsRoute(route)
.shouldSimulateRoute(simulateRoute)
.build();
// Call this method with Context from within an Activity
NavigationLauncher.startNavigation(MainActivity.this, options);
}
});*/
#Override
public void onNavigationReady(boolean isRunning) {
MapboxNavigationOptions.Builder navigationOptions = MapboxNavigationOptions.builder();
NavigationViewOptions.Builder options = NavigationViewOptions.builder();
options.navigationListener(this);
extractRoute(options);
extractConfiguration(options);
options.navigationOptions(navigationOptions.build());
//options.navigationOptions(new MapboxNavigationOptions.Builder().build());
launchNavigationWithRoute();
//navigationView.startNavigation(options.build());
navigationView.initialize(this);
/*MapboxNavigationOptions.Builder navigationOptions = MapboxNavigationOptions.builder();
NavigationViewOptions.Builder options = NavigationViewOptions.builder();
options.navigationListener(this);
extractRoute(options);
options.navigationOptions(navigationOptions.build());
//navigationView = NavigationLauncher.startNavigation(options.build());
navigationView.startNavigation(options.build());
initialize();*/
}
#Override
public void onCancelNavigation() {
// Navigation canceled, finish the activity
showCustomCancel();
finishNavigation();
}
#Override
public void onNavigationFinished() {
}
#Override
public void onNavigationRunning() {
}
private void launchNavigationWithRoute() {
if (route != null) {
NavigationLauncher.startNavigation(this, route);
}
}
private void extractRoute(NavigationViewOptions.Builder options) {
route = NavigationLauncher.extractRoute(this);
options.directionsRoute(route);
}
private void extractConfiguration(NavigationViewOptions.Builder options) {
SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(this);
options.shouldSimulateRoute(preferences.getBoolean(NavigationConstants.NAVIGATION_VIEW_SIMULATE_ROUTE, false));
}
private void finishNavigation() {
NavigationLauncher.cleanUpPreferences(this);
finish();
}
private void showCustomCancel(){
ViewGroup viewGroup = findViewById(android.R.id.content);
View dialogView2 = LayoutInflater.from(this).inflate(R.layout.my_dialog_logout, viewGroup, false);
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setView(dialogView2);
AlertDialog alertDialog2 = builder.create();
Button buttonNo = dialogView2.findViewById(R.id.buttonNo);
Button buttonYes = dialogView2.findViewById(R.id.buttonYes);
buttonYes.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (alertDialog2 != null && alertDialog2.isShowing()) {
alertDialog2.dismiss();
}
Intent intentCancelTrip_Yes = new Intent(getApplicationContext(),MainActivity.class);
startActivity(intentCancelTrip_Yes);
finish();
navigationView.stopNavigation();
}
});
buttonNo.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (alertDialog2 != null && alertDialog2.isShowing()) {
alertDialog2.dismiss();
}
navigationView.onResume();
}
});
alertDialog2.show();
}
/* private void initialize() {
Parcelable position = getIntent().getParcelableExtra(NavigationConstants.NAVIGATION_VIEW_INITIAL_MAP_POSITION);
if (position != null) {
navigationView.initialize(this, (CameraPosition) position);
} else {
navigationView.initialize(this);
}
}*/
#Override
public void onStart() {
super.onStart();
navigationView.onStart();
}
#Override
public void onResume() {
super.onResume();
navigationView.onResume();
}
#Override
public void onLowMemory() {
super.onLowMemory();
navigationView.onLowMemory();
}
#Override
public void onBackPressed() {
// If the navigation view didn't need to do anything, call super
if (!navigationView.onBackPressed()) {
super.onBackPressed();
}
}
#Override
protected void onSaveInstanceState(Bundle outState) {
navigationView.onSaveInstanceState(outState);
super.onSaveInstanceState(outState);
}
#Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {
super.onRestoreInstanceState(savedInstanceState);
navigationView.onRestoreInstanceState(savedInstanceState);
}
#Override
public void onPause() {
super.onPause();
navigationView.onPause();
}
#Override
public void onStop() {
super.onStop();
navigationView.onStop();
}
#Override
protected void onDestroy() {
super.onDestroy();
navigationView.onDestroy();
}
}
NavigationLauncher class i am using to try initiate the navigation inside the Go activity
public class NavigationLauncher {
public static void startNavigation(Activity activity, DirectionsRoute route) {
SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(activity);
SharedPreferences.Editor editor = preferences.edit();
editor.putString(NavigationConstants.NAVIGATION_VIEW_ROUTE_KEY, new Gson().toJson(route));
//editor.putString(NavigationConstants.NAVIGATION_VIEW_AWS_POOL_ID, awsPoolId);
//editor.putBoolean(NavigationConstants.NAVIGATION_VIEW_SIMULATE_ROUTE, simulateRoute);
editor.apply();
Intent navigationActivity = new Intent(activity, Go.class);
activity.startActivity(navigationActivity);
}
/* public static void startNavigation(Activity activity, NavigationLauncherOptions options){
SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(activity);
SharedPreferences.Editor editor = preferences.edit();
storeDirectionsRouteValue(options, editor);
storeConfiguration(options, editor);
editor.apply();
Intent navigationActivity = new Intent(activity, Go.class);
storeInitialMapPosition(options, navigationActivity);
activity.startActivity(navigationActivity);
}*/
private static void storeConfiguration(NavigationLauncherOptions options, SharedPreferences.Editor editor) {
editor.putBoolean(NavigationConstants.NAVIGATION_VIEW_SIMULATE_ROUTE, options.shouldSimulateRoute());
}
private static void storeDirectionsRouteValue(NavigationLauncherOptions options, SharedPreferences.Editor editor) {
editor.putString(NavigationConstants.NAVIGATION_VIEW_ROUTE_KEY, options.directionsRoute().toJson());
/*if (options.directionsRoute() != null) {
storeDirectionsRouteValue(options, editor);
}
else {
throw new RuntimeException("A valid DirectionsRoute or origin and "
+ "destination must be provided in NavigationViewOptions");
}*/
}
static DirectionsRoute extractRoute(Context context) {
SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(context);
String directionsRouteJson = preferences.getString(NavigationConstants.NAVIGATION_VIEW_ROUTE_KEY, "");
return DirectionsRoute.fromJson(directionsRouteJson);
}
static void cleanUpPreferences(Context context) {
SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(context);
SharedPreferences.Editor editor = preferences.edit();
editor
.remove(NavigationConstants.NAVIGATION_VIEW_ROUTE_KEY)
.remove(NavigationConstants.NAVIGATION_VIEW_SIMULATE_ROUTE)
.apply();
}
private static void storeInitialMapPosition(NavigationLauncherOptions options, Intent navigationActivity) {
if (options.initialMapCameraPosition() != null) {
navigationActivity.putExtra(
NavigationConstants.NAVIGATION_VIEW_INITIAL_MAP_POSITION, options.initialMapCameraPosition()
);
}
}
}

I assume that the application crashes once the activity "Go.java" is launched.
The problem appears to be that you are not instantiating the Mapbox object in this activity. You are doing it correclty in your "mainactivity.java" however you are missing it in "go.java". Make sure to have the line Mapbox.getInstance(this, getString(R.string.access_token)); also in your "go.java" activity before calling setContentView()
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Mapbox.getInstance(this, getString(R.string.access_token));
setContentView(R.layout.activity_main);

How to call a specific Fragment's getActivity()?

My problem is that i have a recyclerview implemented on a fragment that uses Room. RecyclerView, Adapter and Database need to be together in one class (i guess).
My problem is that if I put them into StudentActivity,
recyclerView = findViewById(R.id.SubjectRecyclerView);
will be null, because the Fragment won't be available by the time this function called.
If i put them into StudentSubjectsFragment,
everything would be good, but NewSubjectDialogFragment tells me that StudentActivity needs to implement NewSubjectDialogFragment because of this:
private NewSubjectDialogListener listener;
#Override
public void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
FragmentActivity activity = getActivity();
if (activity instanceof NewSubjectDialogListener) {
listener = (NewSubjectDialogListener) activity;
} else {
throw new RuntimeException("Activity must implement the NewSubjectDialogListener interface!");
}
}
If at the
FragmentActivity activity = getActivity();
line somehow I would be able to call the getActivity() function of StudentSubjectsFragment class, I think it would solve my problem, and then the class that would implement the NewSubjectDialogFragment would be the StudentSubjectsFragment instead of StudentActivity.
I tried this:
FragmentActivity activity = getActivity().getSupportFragmentManager().findFragmentByTag("StudentSubjectsFragment").getActivity();
But activity is null.
StudentSubjectsFragment class:
public class StudentSubjectsFragment extends Fragment
implements NewSubjectDialogFragment.NewSubjectDialogListener,
SubjectAdapter.SubjectClickListener {
public static final String TAG = "StudentSubjectsFragment";
private RecyclerView recyclerView;
private SubjectAdapter adapter;
private SubjectDatabase database;
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container,
#Nullable Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.student_subjects, container, false);
FloatingActionButton fab = rootView.findViewById(R.id.fabbb);
fab.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
new NewSubjectDialogFragment().show(getActivity().getSupportFragmentManager(), NewSubjectDialogFragment.TAG);
}
});
database = Room.databaseBuilder(
getActivity(),
SubjectDatabase.class,
"subject-list"
).build();
recyclerView = rootView.findViewById(R.id.SubjectRecyclerView);
adapter = new SubjectAdapter(this);
loadItemsInBackground();
recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
recyclerView.setAdapter(adapter);
return rootView;
}
private void loadItemsInBackground() {
new AsyncTask<Void, Void, List<Subject>>() {
#Override
protected List<Subject> doInBackground(Void... voids) {
return database.subjectDao().getAll();
}
#Override
protected void onPostExecute(List<Subject> subjects) {
adapter.update(subjects);
}
}.execute();
}
#Override
public void onItemChanged(final Subject item) {
new AsyncTask<Void, Void, Boolean>() {
#Override
protected Boolean doInBackground(Void... voids) {
database.subjectDao().update(item);
return true;
}
#Override
protected void onPostExecute(Boolean isSuccessful) {
Log.d("StudentActivity", "Subject update was successful");
}
}.execute();
}
#Override
public void onItemDeleted(final Subject item) {
new AsyncTask<Void, Void, Boolean>() {
#Override
protected Boolean doInBackground(Void... voids) {
database.subjectDao().deleteItem(item);
return true;
}
}.execute();
}
#Override
public void onSubjectCreated(final Subject newItem) {
new AsyncTask<Void, Void, Subject>() {
#Override
protected Subject doInBackground(Void... voids) {
newItem.id = database.subjectDao().insert(newItem);
return newItem;
}
#Override
protected void onPostExecute(Subject subject) {
adapter.addItem(subject);
}
}.execute();
}
}
StudentActivity class:
public class StudentActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_student);
ViewPager vpProfile = findViewById(R.id.vpStudent);
vpProfile.setAdapter(new StudentPagerAdapter(getSupportFragmentManager()));
}
}
NewSubjectDialogFragment class:
public class NewSubjectDialogFragment extends DialogFragment {
private EditText nameEditText;
public static final String TAG = "NewSubjectDialogFragment";
public interface NewSubjectDialogListener {
void onSubjectCreated(Subject newItem);
}
private NewSubjectDialogListener listener;
#Override
public void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
FragmentActivity activity = getActivity().getSupportFragmentManager().findFragmentByTag("StudentSubjectsFragment").getActivity();
if (activity instanceof NewSubjectDialogListener) {
listener = (NewSubjectDialogListener) activity;
} else {
throw new RuntimeException("Activity must implement the NewSubjectDialogListener interface!");
}
}
private boolean isValid() {
return nameEditText.getText().length() > 0;
}
private Subject getSubject() {
Subject subject = new Subject();
subject.name = nameEditText.getText().toString();
return subject;
}
#NonNull
#Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
return new AlertDialog.Builder(requireContext())
.setTitle(R.string.new_subject_item)
.setView(getContentView())
.setPositiveButton(R.string.ok, new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialogInterface, int i) {
if (isValid()) {
listener.onSubjectCreated(getSubject());
}
}
})
.setNegativeButton(R.string.cancel, null)
.create();
}
private View getContentView() {
final View contentView = LayoutInflater.from(getContext()).inflate(R.layout.dialog_new_subject_item, null);
nameEditText = contentView.findViewById(R.id.SubjectNameEditText);
return contentView;
}
}
I think there is a way to change NewSubjectDialogFragment to work with StudentSubjectsFragment but I am a beginner in android developing and don't know how to do it.

Solution of Mike M. worked perfectly.
The working code parts are the following:
NewSubjectDialogFragment:
#Override
public void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Fragment fragment = getParentFragment();
if (fragment instanceof NewSubjectDialogListener) {
listener = (NewSubjectDialogListener) fragment;
} else {
throw new RuntimeException("Fragment must implement the NewSubjectDialogListener interface!");
}
}
StudentSubjectFragment:
FloatingActionButton fab = rootView.findViewById(R.id.fabbb);
fab.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
new NewSubjectDialogFragment().show(getChildFragmentManager(), NewSubjectDialogFragment.TAG);
}
});

Android - NullPointerException after trying to call getSerializableExtra() method (which it works) [duplicate]

This question already has answers here:
What is a NullPointerException, and how do I fix it?
(12 answers)
Closed 5 years ago.
I'm trying to understand how Java serialization works, so I'm trying to add to my own Android app the possibility to transfer two strings (First and Last Name, to be precise) and then displaying in another activity a simple 'welcome' message with both strings.
The things just start to get really weird because I actually manage to transfer the two strings, but when it comes to displaying them.. I "lose" them and I get a NullPointerException!
Anyway, here's the code:
MainActivity.java
public class MainActivity extends AppCompatActivity {
private Button personalData;
protected String strUsername;
private boolean isProfileReady;
TextView welcome;
protected SharedPreferences loginData;
SharedPreferences wizardPrefs;
SharedPreferences.Editor wizardEditor;
DataUser userData;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
welcome = (TextView) findViewById(R.id.welcome);
personalData = (Button) findViewById(R.id.data);
personalData.setText("Personal Data");
personalData.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(MainActivity.this, WizardActivity.class);
intent.putExtra("profileReady", isProfileReady);
startActivity(intent);
}
});
loginData = getSharedPreferences("UserPrefs", MODE_PRIVATE);
wizardPrefs = this.getSharedPreferences("USERDATA", MODE_PRIVATE);
String value = loginData.getString("Username", null);
welcome.setText("Welcome " + loginData.getString("Username", strUsername) + "!");
}
#Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (resultCode == RESULT_OK) {
isProfileReady = true;
personalData.setText("My Profile");
welcome.setText("Welcome " + userData.getStrFName() + " " + userData.getStrLName() + "!");
}
}
}
WizardActivity.java
public class WizardActivity extends AppCompatActivity implements SummaryFragment.Images {
public DataUser userData;
//region Variables
Button go;
WizardOne wizOne;
WizardTwo wizTwo;
WizardThree wizThree;
SummaryFragment summaryFragment;
Bitmap frontBitmap, backBitmap;
SharedPreferences wizardPrefs;
Bundle bundle = new Bundle();
String pathOne, pathTwo;
int currentPage = 1;
public static final String FRONT_BITMAP_KEY = "frontBitmap", BACK_BITMAP_KEY = "backBitmap";
boolean isProfileReady;
//endregion
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
userData = new DatiUtente();
isProfileReady = getIntent().getBooleanExtra("profileReady", false);
Toast.makeText(this, "profileReady : " + isProfileReady, Toast.LENGTH_SHORT).show();
setContentView(R.layout.wizard_layout);
go = (Button) findViewById(R.id.go);
if (isProfileReady) {
currentPage = 4;
go.setText("Home");
wizardPrefs = this.getSharedPreferences("USERDATA", MODE_PRIVATE);
summaryFragment = new SummaryFragment();
summaryFragment.setArguments(bundle);
getSupportFragmentManager().beginTransaction().add(R.id.activity_layout, summaryFragment).commit();
} else {
wizOne = new WizardOne(userData);
if (savedInstanceState == null)
getSupportFragmentManager().beginTransaction().add(R.id.activity_layout, wizOne).commit();
}
go.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (isProfileReady) {
Intent intent = new Intent();
setResult(RESULT_OK, intent);
finish();
} else {
nextFragment();
}
}
});
}
public void nextFragment() {
switch (currentPage) {
case 1:
if (wizOne.validate()) {
wizTwo = new WizardTwo();
changeFragment(wizTwo, R.id.activity_layout);
currentPage++;
} else {
Toast.makeText(getApplicationContext(), "Riempire i campi", Toast.LENGTH_SHORT).show();
}
break;
case 2:
if (wizTwo.validate()) {
wizThree = new WizardThree(getApplicationContext());
changeFragment(wizThree, R.id.activity_layout);
currentPage++;
} else {
Toast.makeText(getApplicationContext(), "Riempire i campi", Toast.LENGTH_SHORT).show();
}
break;
case 3:
if (wizThree.validate()) {
bundle.putParcelable("frontBitmap", wizThree.getFrontBitmap());
bundle.putParcelable("backBitmap", wizThree.getBackBitmap());
summaryFragment = new SummaryFragment();
summaryFragment.setArguments(bundle);
go.setText("Home");
changeFragment(summaryFragment, R.id.activity_layout);
currentPage++;
}
break;
case 4:
passImages();
// setResult(RESULT_OK);
Intent intent = new Intent(this, SerializableWelcome.class);
intent.putExtra("dataUser", userData);
startActivity(intent);
// finish();
break;
default:
break;
}
}
public void changeFragment(ValidateFragment f, int resource) {
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction transaction = fragmentManager.beginTransaction();
transaction.replace(resource, f);
transaction.addToBackStack(null);
transaction.commit();
}
public Bitmap getFrontBitmap() {
return frontBitmap;
}
public Bitmap getBackBitmap() {
return backBitmap;
}
#Override
public void onBackPressed() {
if (currentPage > 1) {
currentPage--;
getSupportFragmentManager().popBackStack();
} else {
super.onBackPressed();
}
}
#Override
public Bundle passImages() {
bundle.getParcelable("frontBitmap");
bundle.getParcelable("backBitmap");
return bundle;
}
}
SerializableWelcome.java
public class SerializableWelcome extends AppCompatActivity {
TextView showName;
DataUser userData;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_web_services_main);
showName = (TextView) findViewById(R.id.welcomeFromSummary);
Intent intent = getIntent();
if (intent != null) {
userData = (DataUser) intent.getSerializableExtra("dataUser");
}
showName.setText("Welcome " + userData.getStrFName() + " " + userData.getStrLName() + "!");
}
}
DataUser.java
public class DataUser implements Parcelable {
String strFName, strLName, strFisCode, strBirth, strCity, strZip, strProv, strCC, strIban, strMail;
public DataUser(){}
protected DataUser(Parcel in) {
//region in.readString()
strFName = in.readString();
strLName = in.readString();
strFisCode = in.readString();
strBirth = in.readString();
strCity = in.readString();
strZip = in.readString();
strProv = in.readString();
strCC = in.readString();
strIban = in.readString();
strMail = in.readString();
//endregion
}
public static final Creator<DataUser> CREATOR = new Creator<DataUser>() {
#Override
public DataUser createFromParcel(Parcel in) {
return new DataUser(in);
}
#Override
public DataUser[] newArray(int size) {
return new DataUser[size];
}
};
#Override
public int describeContents() {
return 0;
}
#Override
public void writeToParcel(Parcel dest, int flags) {
//region dest.writeString()
dest.writeString(strFName);
dest.writeString(strLName);
dest.writeString(strFisCode);
dest.writeString(strBirth);
dest.writeString(strCity);
dest.writeString(strZip);
dest.writeString(strProv);
dest.writeString(strCC);
dest.writeString(strIban);
dest.writeString(strMail);
//endregion
}
//region Getter and Setter
public String getStrFName() {
return strFName;
}
public void setStrFName(String strFName) {
this.strFName = strFName;
}
public String getStrLName() {
return strLName;
}
public void setStrLName(String strLName) {
this.strLName = strLName;
}
public String getStrFisCode() {
return strFisCode;
}
public void setStrFisCode(String strFisCode) {
this.strFisCode = strFisCode;
}
public String getStrBirth() {
return strBirth;
}
public void setStrBirth(String strBirth) {
this.strBirth = strBirth;
}
public String getStrCity() {
return strCity;
}
public void setStrCity(String strCity) {
this.strCity = strCity;
}
public String getStrZip() {
return strZip;
}
public void setStrZip(String strZip) {
this.strZip = strZip;
}
public String getStrProv() {
return strProv;
}
public void setStrProv(String strProv) {
this.strProv = strProv;
}
public String getStrCC() {
return strCC;
}
public void setStrCC(String strCC) {
this.strCC = strCC;
}
public String getStrIban() {
return strIban;
}
public void setStrIban(String strIban) {
this.strIban = strIban;
}
public String getStrMail() {
return strMail;
}
public void setStrMail(String strMail) {
this.strMail = strMail;
}
//endregion
}

This is how you should pass and pull Parcelable object:
// Pass
Intent i = new Intent();
i.putExtra("name_of_extra", myParcelableObject);
// and then pull them:
Intent i = getIntent();
MyParcelable myParcelableObject = (MyParcelable) i.getParcelableExtra("name_of_extra");

In which case getFragmentManager() return null?

Problem : getFragmentManager() return null randomly.
Case: I have one activity with tab. On each tab press I'm replacing the content container with fragment. In case of two fragment I'm doing network hit to fetch data from a server. For that I have written the following code:
public class FetchMessagesyFragmentTask extends Fragment {
private static final String TAG_EXTRA = "tab_extra";
private static final String TAG = "Test";
private String mData;
public static final FetchMessagesyFragmentTask newInstance(String data) {
FetchMessagesyFragmentTask fragment = new FetchMessagesyFragmentTask();
Bundle bundle = new Bundle();
bundle.putString(TAG_EXTRA, data);
fragment.setArguments(bundle);
return fragment;
}
public static interface TaskCallbacks {
void onPreExecute();
void onCancelled();
void onPostExecute(MessageResponse response);
}
private TaskCallbacks mCallbacks;
private FetchMessage mTask;
private boolean mRunning;
#Override
public void onAttach(Activity activity) {
super.onAttach(activity);
if (!(getTargetFragment() instanceof TaskCallbacks)) {
throw new IllegalStateException(
"Target fragment must implement the TaskCallbacks interface.");
}
mCallbacks = (TaskCallbacks) getTargetFragment();
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setRetainInstance(true);
mData = getArguments().getString(TAG_EXTRA);
}
#Override
public void onDestroy() {
super.onDestroy();
cancel();
}
public void execute(String data) {
if (!mRunning) {
mTask = new FetchMessage();
mTask.execute(data);
mRunning = true;
}
}
public void cancel() {
if (mRunning) {
mTask.cancel(false);
mTask = null;
mRunning = false;
}
}
public boolean isRunning() {
return mRunning;
}
private class FetchMessage extends AsyncTask<String, Void, MessageResponse> {
private ProgressDialogFragment progressDialog;
#Override
protected void onPreExecute() {
progressDialog = new ProgressDialogFragment.Builder().setMessage(
"Please wait...").build();
progressDialog.show(((Fragment) mCallbacks).getFragmentManager(),
"task_progress");
mCallbacks.onPreExecute();
mRunning = true;
}
#Override
protected MessageResponse doInBackground(String... params) {
//Doing network hit here and returning value.
return value;
}
#Override
protected void onCancelled() {
mCallbacks.onCancelled();
mRunning = false;
}
#Override
protected void onPostExecute(MessageResponse response) {
if (mCallbacks != null) {
FragmentManager manager = ((Fragment) mCallbacks)
.getFragmentManager();
//XXXXXXXX GETTING MANAGER AS NULL HERE SOMETIME XXXXXXXXXXXXXX
progressDialog.dismiss(manager);
if (response != null) {
if (Integer.parseInt(response.getResponseCode()) == NetworkConstant.SUCCESS
&& response.getChatMessage() != null) {
saveDataToDb(response);
}
}
mCallbacks.onPostExecute(response);
mRunning = false;
}
}
private void saveDataToDb(MessageResponse response) {
//SaveToDB
}
}
}
I'm following this url to handle network hit on orientation change. I have commented the line where I'm getting the issue.
Note
This code work fine in normal situation but crash when I switch tabs very fast.

The value of the variable has been suddenly set to 0

I'm doing an activity to measure how long it takes a person to do an exercise, but it has a bug that I couldn't resolve yet...
The TrainingFragment shows a list of exercises that the user can click and then my ExerciseActivity is launched and runs until the variable "remainingsSets" is setted to 0.
When I click in the first time at any exercise, everything works fine, the ExerciseActivity works correctly end return to the TrainingFragment. But then, if I try to click in another exercise, the ExerciseActivity is just closed.
In my debug, I could see that the variable "remainingSets" comes with it's right value (remainingSets = getIntent().getIntExtra("remaining_sets", 3)), but when the startButton is clicked, I don't know why the variable "remainingSets" is setted to 0 and then the activity is closed because this condition: if (remainingSets > 0){...}.
Here is my TrainingFragment:
public class TrainingFragment extends Fragment {
private final static int START_EXERCISE = 1;
private Training training;
private String lastItemClicked;
private String[] values;
#Override
public void onAttach(Activity activity) {
super.onAttach(activity);
Bundle bundle = getArguments();
if (bundle != null) {
training = bundle.getParcelable("training");
}
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return (ScrollView) inflater.inflate(R.layout.template_exercises, container, false);
}
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
LinearLayout exercisesContainer = (LinearLayout) getView().findViewById(R.id.exercises);
LayoutInflater inflater = (LayoutInflater) getActivity().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
List<Exercise> exercises = training.getExercises();
values = new String[exercises.size()];
if (savedInstanceState != null) {
values = savedInstanceState.getStringArray("values");
}
for (int i = 0; i < exercises.size(); i++) {
final View exerciseView = inflater.inflate(R.layout.template_exercise, null);
exerciseView.setTag(String.valueOf(i));
TextView remainingSets = (TextView) exerciseView.findViewById(R.id.remaining_sets);
if (savedInstanceState != null) {
remainingSets.setText(values[i]);
} else {
String sets = exercises.get(i).getSets();
remainingSets.setText(sets);
values[i] = sets;
}
exerciseView.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(getActivity(), ExerciseActivity.class);
intent.putExtra("remaining_sets",
Integer.valueOf(((TextView) v.findViewById(R.id.remaining_sets)).getText().toString()));
lastItemClicked = v.getTag().toString();
startActivityForResult(intent, START_EXERCISE);
}
});
exercisesContainer.addView(exerciseView);
}
}
#Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
outState.putStringArray("values", values);
}
#Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
View view = ((LinearLayout) getView().findViewById(R.id.exercises)).findViewWithTag(lastItemClicked);
if (requestCode == START_EXERCISE) {
if (resultCode == Activity.RESULT_OK) { // the exercise had been
// finished.
((TextView) view.findViewById(R.id.remaining_sets)).setText("0");
view.setClickable(false);
values[Integer.valueOf(lastItemClicked)] = "0";
} else if (resultCode == Activity.RESULT_CANCELED) {
String remainingSets = data.getStringExtra("remaining_sets");
((TextView) view.findViewById(R.id.remaining_sets)).setText(remainingSets);
values[Integer.valueOf(lastItemClicked)] = remainingSets;
}
}
}
}
My ExerciseActivity:
public class ExerciseActivity extends Activity {
private Chronometer chronometer;
private TextView timer;
private Button startButton;
private Button endButton;
private int remainingSets;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_exercise);
ExerciseEvents.addExerciseListener(new PopupExerciseListener());
chronometer = (Chronometer) findViewById(R.id.exercise_doing_timer);
timer = (TextView) findViewById(R.id.timer);
startButton = (Button) findViewById(R.id.start_exercise);
startButton.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
ExerciseEvents.onExerciseBegin();
}
});
endButton = (Button) findViewById(R.id.end_exercise);
endButton.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
ExerciseEvents.onExerciseRest();
}
});
}
#Override
public void onBackPressed() {
Intent intent = new Intent();
intent.putExtra("remaining_sets", String.valueOf(remainingSets));
setResult(RESULT_CANCELED, intent);
super.onBackPressed();
}
public class PopupExerciseListener implements ExerciseListener {
public PopupExerciseListener() {
remainingSets = getIntent().getIntExtra("remaining_sets", 3);
}
#Override
public void onExerciseBegin() {
if (remainingSets > 0) {
chronometer.setVisibility(View.VISIBLE);
timer.setVisibility(View.GONE);
chronometer.setBase(SystemClock.elapsedRealtime());
chronometer.start();
startButton.setVisibility(View.GONE);
endButton.setVisibility(View.VISIBLE);
} else {
ExerciseEvents.onExerciseFinish();
}
}
#Override
public void onExerciseFinish() {
setResult(RESULT_OK);
finish();
}
#Override
public void onExerciseRest() {
chronometer.setVisibility(View.GONE);
endButton.setVisibility(View.GONE);
timer.setVisibility(View.VISIBLE);
long restTime = getIntent().getLongExtra("time_to_rest", 60) * 1000;
new CountDownTimer(restTime, 1000) {
#Override
public void onTick(long millisUntilFinished) {
timer.setText(String.valueOf(millisUntilFinished / 1000));
}
#Override
public void onFinish() {
ExerciseEvents.onExerciseBegin();
}
}.start();
remainingSets--;
}
}
}
And my ExerciseEvents:
public class ExerciseEvents {
private static LinkedList<ExerciseListener> mExerciseListeners = new LinkedList<ExerciseListener>();
public static void addExerciseListener(ExerciseListener listener) {
mExerciseListeners.add(listener);
}
public static void removeExerciseListener(String listener) {
mExerciseListeners.remove(listener);
}
public static void onExerciseBegin() {
for (ExerciseListener l : mExerciseListeners) {
l.onExerciseBegin();
}
}
public static void onExerciseRest() {
for (ExerciseListener l : mExerciseListeners) {
l.onExerciseRest();
}
}
public static void onExerciseFinish() {
for (ExerciseListener l : mExerciseListeners) {
l.onExerciseFinish();
}
}
public static interface ExerciseListener {
public void onExerciseBegin();
public void onExerciseRest();
public void onExerciseFinish();
}
}
Could anyone give me any help?

After you updated your code, I see you have a big memory leak in your code:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_exercise);
ExerciseEvents.addExerciseListener(new PopupExerciseListener());
....
}
The call ExerciseEvents.addExerciseListener(new PopupExerciseListener()) adds a new PopupExerciseListener to a static/global list: ExcerciseEvents.mExerciseListeners. Since the class PopupExerciseListener is an inner-class, it implicitly holds a reference to its enclosing ExcerciseActivity. This mean your code is holding on to each instance of ExcerciseActivity forever. Not good.
This may also explain the weird behavior you see. When one of the onExcersizeXXX() methods is called, it will call all ExcerciseListeners in the linked-list, the ones from previous screens and the current one.
Try this in your ExcerciseActivity.java:
....
ExerciseListener mExerciseListener;
....
#Override
protected void onCreate(Bundle savedInstanceState) {
....
....
mExerciseListener = new PopupExerciseListener()
ExerciseEvents.addExerciseListener(mExerciseListener);
....
....
}
#Override
protected void onDestroy() {
ExerciseEvents.removeExerciseListener(mExerciseListener);
super.onDestroy();
}
....
In onDestroy, you deregister your listener, preventing a memory leak and preventing odd multiple callbacks to PopupExerciseListeners that are attached to activities that no longer exist.

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