Develop Reference

Create mapbox markers from a database

I'm new in android and java and I'm programming my first app in Android Studio with a database and a Mapbox Map. I have few Activities and a database in .SQLite using Room persistence library. Right now I'm programming a Mapbox Activity.
I'm programming an activity which shows the map. This map visualizes several markers. Now I want to implement small annotations with information for each marker (e.g. address, house number, coordinates) after clicking on.
At the moment the markers themselves are created by going through a List with a for loop.
How can I create an annotation window without a geoJSON file, but with accessing the SQLite database. Is it possible? I found only examples like this: https://docs.mapbox.com/android/maps/examples/symbol-layer-info-window/?size=n_10_n which uses a geoJSON file, which is transformed to a List, but I have only a List.
How is the best way to implement the example with SQLite database as source?
Thank you in advance!
#Override
public void onMapReady(#NonNull final MapboxMap mapboxMap) {
MapboxActivity.this.mapboxMap = mapboxMap;
mapboxMap.setStyle(
new Style.Builder().fromUri("mapbox://styles/aroid435/ckiohlr9a0c3m17nq6tx5ajjs")
,
new Style.OnStyleLoaded() {
#Override
public void onStyleLoaded(#NonNull Style style) {
enableLocationComponent(style);
SymbolManager symbolManager = new SymbolManager(mapView, mapboxMap, style);
mapboxMap.animateCamera(CameraUpdateFactory.newCameraPosition(new CameraPosition.Builder().target(new LatLng(51.051877, 13.741517)).zoom(10.5).build()));
for (int i= 0; i < stolpersteine_list.size() ; i = i+1 ) {
mapboxMap.getStyle().addImage("my-star-marker", BitmapFactory.decodeResource(getResources(), R.drawable.rectangle));
symbolManager.create(new SymbolOptions()
.withLatLng(new LatLng( stolpersteine_list.get(i).getLatitude(),stolpersteine_list.get(i).getLongitude()))
.withIconImage("my-star-marker")
.withIconAnchor("bottom"));
}
}
});
} // end of onMapReady
´´´

I find the way, how to convert my database into mapbox List.
Here is my code:
#Override
public void onMapReady(#NonNull final MapboxMap mapboxMap) {
MapboxActivity.this.mapboxMap = mapboxMap;
List<Feature> symbolLayerIconFeatureList = new ArrayList<>();
Log.d("tg", String.valueOf(symbolLayerIconFeatureList));
for (int i = 0; i < stolpersteine_list.size(); i = i + 1) {
symbolLayerIconFeatureList.add(Feature
.fromGeometry(Point.fromLngLat(stolpersteine_list.get(i).getLongitude(), stolpersteine_list.get(i).getLatitude())));
Log.d("tag", String.valueOf(symbolLayerIconFeatureList));
}
mapboxMap.setStyle(
new Style.Builder().fromUri("mapbox://styles/aroid435/ckiohlr9a0c3m17nq6tx5ajjs")
.withSource(new GeoJsonSource(SOURCE_ID,
FeatureCollection.fromFeatures(symbolLayerIconFeatureList)))
.withImage(ICON_ID, BitmapFactory.decodeResource(
MapboxActivity.this.getResources(), R.drawable.rectangle))
.withLayer(new SymbolLayer(LAYER_ID, SOURCE_ID)
.withProperties(
iconImage(ICON_ID),
iconAllowOverlap(true),
iconIgnorePlacement(true)
)
), new Style.OnStyleLoaded() {
#Override
public void onStyleLoaded(#NonNull Style style) {
enableLocationComponent(style);
SymbolManager symbolManager = new SymbolManager(mapView, mapboxMap, style);
mapboxMap.animateCamera(CameraUpdateFactory.newCameraPosition(new CameraPosition.Builder().target(new LatLng(51.051877, 13.741517)).zoom(10.5).build()));
}
});
} // end of onMapReady
but now I don't know how to add a properties to a point. This way I can only vizualize the markers, but I cannot add other values to the List and plot the annotation window. I cannot use the addStringProperty(String key, String value) or addProperty(String key, com.google.gson.JsonElement value), in my for loop, because I get error that: Non-static method 'addStringProperty(java.lang.String, java.lang.String)' cannot be referenced from a static context.
https://docs.mapbox.com/archive/android/java/api/libjava-geojson/2.1.0/com/mapbox/services/commons/geojson/Feature.html
Do somebody know how to do it?

AbstractContributionFactory Does Not Work In E4

We have AbstractContributionFactorys like these:
final AbstractContributionFactory contributions = new AbstractContributionFactory("org.acme.mainMenu", null) {
#Override
public void createContributionItems(final IServiceLocator serviceLocator,
final IContributionRoot contributionRoot) {
String subMenuId ="org.acme.subMenu";
final MenuManager subMenu = new MenuManager("Sub menu", subMenuId );
contributionRoot.addContributionItem(subMenu, AlwaysEnabledExpression.INSTANCE);
menuService.addContributionFactory(new AbstractContributionFactory("menu:" + subMenuId, null) {
#Override
public void createContributionItems(final IServiceLocator serviceLocator1,
final IContributionRoot additions) {
additions.addContributionItem(new ActionContributionItem(new Action("Sub action") {
}), AlwaysEnabledExpression.INSTANCE);
}
});
}
};
menuService.addContributionFactory(contributions);
This code worked perfectly in Eclipse 3.x, but stopped working in E4. So while searching for the bug we found a lot uncommented code in the E4 framework, as much as two blocks in WorkbenchMenuService.addContributionFactory(...) alone. What I assume produces the bug is:
// // OK, now update any managers that use this uri
// for (Map.Entry<ContributionManager, MenuLocationURI> entry :
// managers.entrySet()) {
// MenuLocationURI mgrURI = entry.getValue();
// if (mgrURI.getScheme().equals(location.getScheme())
// && mgrURI.getPath().equals(location.getPath())) {
// ContributionManager mgr = entry.getKey();
// populateContributionManager(mgr, mgrURI.toString());
// mgr.update(true);
// }
// }
According to the comments on the associated bug a lot of people have the same problem.
Did anyone find a workaround for the bug?

I also wanted to programmatically add some menu items to the main menu of an RCP application and was caught out by this bug.
Instead of using the WorkbenchMenuService.addContributionFactory(...) method I found you can add contibution items using the by extending the ExtensionContributionFactory class (which also has a createContributionItems() method), and then add this using the org.eclipse.ui.menus extension point as a new menuContribution.
I found this solution in this blog by Vogella.

How to make multiple windows in Eclipse RCP e4

We want to achieve an RCP application which may have multiple windows (MWindow)
for distinct data. The Windows must be independent (unlike the Eclipse IDE new
window menu entry), but it must be possible to copy & paste, drag & drop things from
one window into another one. Imagine an application like Word where you can
have multiple documents open. We tried various approaches, but it is quiet
difficult to find out the right e4 way:
1. Creating a new E4Application for each window
Our first approach was to create and run a complete new E4Application for each
new window. But this sounds not to be the right e4 way. Also it is buggy: Key
bindings does not work correct and also the LifecycleManager is called for each new
application and therefor for each new window, which should not be.
E4Application application = new E4Application();
BundleContext context = InternalPlatform.getDefault().getBundleContext();
ServiceReference<?> appContextService = context.getServiceReference(IApplicationContext.class);
IApplicationContext iac = (IApplicationContext) context.getService(appContextService);
IWorkbench workbench = application.createE4Workbench(iac, display);
final E4Workbench implementation = (E4Workbench) workbench;
implementation.createAndRunUI(workbench.getApplication());
This seems not the right approach to do it.
2. The Eclipse IDE approach
In the Eclipse IDE you can go to the menu and click Window -> New Window which
will open a complete new top level window. But it is synchronized: Open the
same text file in both windows and editing it in the first one will alter it in
the other one too. Albeit we tried that approach by simply copy and pasting it
from org.eclipse.ui.actions.OpenInNewWindowAction#run():
// Does not work because we do not have the RCP3 workbench in RCP4.
final IWorkbench workbench = PlatformUI.getWorkbench();
final IWorkbenchWindow workbenchWindow = workbench.getActiveWorkbenchWindow();
final IWorkbenchPage activePage = workbenchWindow.getActivePage();
final String perspectiveId;
if (activePage != null && activePage.getPerspective() != null) {
perspectiveId = activePage.getPerspective().getId();
} else {
perspectiveId = workbenchWindow.getWorkbench().getPerspectiveRegistry().getDefaultPerspective();
}
workbenchWindow.getWorkbench().openWorkbenchWindow(perspectiveId, null);
It looks like that the Eclipse IDE uses the RCP3 compatibility layer. We didn't
found a way to obtain the IWorkbench object. Neither by
PlatformUI#getWorkbench(), nor via the application context, nor the bundle
context.
3. Clone the main window
We stumbled upon Opening multiple instances of an MTrimmedWindow complete with perspectives etc
n-mtrimmedwindow-complete-with-perspectives-etc and did a lot of trial and
error and came up with this muddy code:
class ElementCloningBasedCreator {
EModelService models = ...; // injected
MApplication app = ...; // injected
public void openNewWindow() {
MWindow originWindow = (MWindow) models.find("the.main.window.id", app);
MWindow newWindow = (MWindow) models.cloneElement(originWindow, null);
MPerspectiveStack newPerspectiveStack =
(MPerspectiveStack) models.find(the.main.perspective.stack.id, newWindow);
newPerspectiveStack.setParent((MElementContainer) newWindow);
addTo(app, newWindow);
// Clone the shared elements. If we don't do that the rendering somewhere
// deep in the rabbit hole throws assertion erros because the recurisve
// finding of an element fails because the search root is null.
for (final MUIElement originSharedElement : originWindow.getSharedElements()) {
final MUIElement clonedSharedElement = models.cloneElement(originSharedElement, null);
clonedSharedElement.setParent((MElementContainer) newWindow);
newWindow.getSharedElements().add(clonedSharedElement);
}
cloneSnippets(app, originWindow, newPerspectiveStack, newWindow);
newWindow.setContext(createContextForNewWindow(originWindow, newWindow));
newWindow.setToBeRendered(true);
newWindow.setVisible(true);
newWindow.setOnTop(true);
models.bringToTop(newWindow);
}
#SuppressWarnings({ "rawtypes", "unchecked" })
private void addTo(MElementContainer target, MUIElement child) {
child.setParent(target);
target.getChildren().add(child);
}
/**
* Clone each snippet that is a perspective and add the cloned perspective
* into the main PerspectiveStack.
*/
private void cloneSnippets(MApplication app, MWindow originWindow,
MPerspectiveStack newPerspectiveStack, MWindow newWindow) {
boolean isFirstSnippet = true;
for (MUIElement snippet : app.getSnippets()) {
if (ignoreSnippet(snippet)) {
continue;
}
String snipetId = snippet.getElementId();
MPerspective clonedPerspective =
(MPerspective) models.cloneSnippet(app, snipetId, originWindow);
findPlaceholdersAndCloneReferencedParts(clonedPerspective, newWindow);
addTo(newPerspectiveStack, clonedPerspective);
if (isFirstSnippet) {
newPerspectiveStack.setSelectedElement(clonedPerspective);
isFirstSnippet = false;
}
}
}
private boolean ignoreSnippet(MUIElement snippet) {
return !(snippet instanceof MPerspective);
}
private void findPlaceholdersAndCloneReferencedParts(MPerspective clonedPerspective, MWindow newWindow) {
List<MPlaceholder> placeholders =
models.findElements(clonedPerspective, null, MPlaceholder.class, null);
for (MPlaceholder placeholder : placeholders) {
MUIElement reference = placeholder.getRef();
if (reference != null) {
placeholder.setRef(models.cloneElement(placeholder.getRef(), null));
placeholder.getRef().setParent((MElementContainer) newWindow);
}
}
}
}
This code does not really work and we really need some hints/advices how to do
it right, because of the lack of official documentation. The questions open are:
Do we need to clone the shared objects and if not how do we prevent the
errors during rendering)?
We only saw code where the cloned elements are
added to the parent via getChildren().add(), but we found out that the
children din't get the parent automatically and it is null though. Is it the
right pattern to add the parent to the child too?
We have the deep feeling
that we are doing it not right. It looks way too complicated what we do here. Is
there a simpler/better approach?

You can use the EModelService cloneSnippet method to do this.
Design your MTrimmedWindow (or whatever type of window you want) in the Snippets section of the Application.e4xmi. Be sure that the To Be Rendered and Visible flags are checked. You may need to set the width and height bounds (and you may want to set the x and y position as well).
Your command handler to create the new window would simply be:
#Execute
public void execute(EModelService modelService, MApplication app)
{
MTrimmedWindow newWin = (MTrimmedWindow)modelService.cloneSnippet(app, "id of the snippet", null);
app.getChildren().add(newWin);
}

Synchronous RPC Calls in GWT

(That title alone should cause people to come out of the woodwork to bash me with clubs, but hear me out).
I have a use case where I need to return a value from a asynchronous call. (I'm using GWT-Platform, but the concepts are the same.) I declared a final JavaScriptObject array, then assigned the value within the AsyncCallback. However, I need to return the value, and the method returns before the AsyncCallback completes. Therefore, I need to block somehow until the AsyncCallback completes. I need the returned value in another method, or I'd just do what I need to in onSuccess().
I've tried loops, Timers, and a few other methods with no luck. Can anyone help?
#Override
public JavaScriptObject doGetWhereAmIMarker(final double lng, final double lat) {
final JavaScriptObject[] markerArray = new JavaScriptObject[1]; // ugly hack, I know
dispatch.execute(new GetLocationDescriptionsAction(lng, lat), new AsyncCallback<GetLocationDescriptionsResult>() {
#Override
public void onFailure(Throwable caught) {
caught.printStackTrace();
}
#Override
public void onSuccess(GetLocationDescriptionsResult result) {
Map<String, Location> resultMap = result.getResult();
StringBuffer message = new StringBuffer();
for (String key : resultMap.keySet()) {
message.append(key).append(": ").append(resultMap.get(key)).append("\n");
}
Map tempMap = new HashMap();
tempMap.put("TITLE","Location Information");
tempMap.put("LAT", lat);
tempMap.put("LNG", lng);
tempMap.put("CONTENTS", message.toString());
JavaScriptObject marker = GoogleMapUtil.createMarker(tempMap);
markerArray[0] = marker;
if (markerArray[0] != null) {
GWT.log("Marker Array Updated");
}
}
});
return markerArray[0];
}
UPDATE: As requested, here is the code that calls doGetWhereIAmMarker(). I've tried having a separate native method with the Google Map object (as a JavaScriptObject) as a parameter, but it appears that passing that object between native methods kills the ability to update said object.
public native void initMap(JavaScriptObject mapOptions, JavaScriptObject bounds, JavaScriptObject border, JsArray markerArray, Element e) /*-{
// create the map and fit it within the given bounds
map = new $wnd.google.maps.Map(e, mapOptions);
if (bounds != null) {
map.fitBounds(bounds);
}
// set the polygon for the borders
if (border != null) {
border.setMap(map);
}
// set up the info windows
if (markerArray != null && markerArray.length > 0) {
var infoWindow = new $wnd.google.maps.InfoWindow({
content:"InfoWindow Content Goes Here"
});
for (var i = 0; i < markerArray.length; i++) {
var marker = markerArray[i];
marker.setMap(map);
$wnd.google.maps.event.addListener(marker, 'click', function() {
infoWindow.setContent(marker.content);
infoWindow.open(map, this);
});
}
}
// need to reference the calling class inside the function(), so set a reference to "this"
var that = this;
$wnd.whereAmI=function(lng, lat) {
that.#org.jason.mapmaker.client.view.MapmakerMapViewImpl::whereAmI(DD)(lng,lat);
}
$wnd.google.maps.event.addListener(map, 'click', function(event) {
var lat = event.latLng.lat();
var lng = event.latLng.lng();
$wnd.whereAmI(lng, lat);
});
}-*/;

At some point I had to do something similar but eventually I eliminated that code in favor of asynchronous stuff. Therefore, I can't give exact code that you need to use but only few pointers on how to approach it.
Firstly, this blog describes how to do synchronous AJAX using javascript.
Second, you must provide support for sync calls. The problem is that GWT does not support the parameter that provides synchronous AJAX calls. Most likely is that they don't want to encourage its use. Therefore you would need to use JSNI to add appropriate method to XMLHttpRequest (which you probably would extend) and then to RequestBuilder (also should extend it).
Finally, amend your service using extended RequestBuilder. Something like
((ServiceDefTarget)service).setRpcRequestBuilder(requestBuilder);
And in conclusion - from the same blog post (slightly out of context):
Because of the danger of a request getting lost and hanging the browser,
synchronous javascript isn't recommended for anything outside of
(onbefore)unload event handlers.

I Think its all fate....
We cannot do in Gwt to catch the Response and Send it, because immediately after the request is send the next method starts executing, neither bothering the response
Still however they satisfy us to use the Timers, is what i think...
Timer t = new Timer() {
#Override
public void run() {
Window.alert("Nifty, eh?");
}
};
t.schedule(5000);

Eclipse JFace's Wizards

I need a wizard which second page content depends on the first page's selection. The first page asks the user the "kind" of filter he wants to create and the second one asks the user to create one filter instance of the selected "kind".
JFace's wizards pages contents (createControl(...) method) are all created when the wizard is open and not when a given page is displayed (this allow JFace to know the wizard size I guess ??).
Because of this, I have to create my second page content BEFORE the wizard is opened BUT I can't since the second page's content depends on the first page selection.
For now the cleaner solution I found consists in creating all (seconds) pages before the wizard is open (with their content) and override the getNextPage() method in the first page's implementation.
The main drawback of that solution is that it can be be expensive when there are many second pages to create.
What do you think about that solution ? How do you manage your wizard's pages ? Is there any cleaner solution I missed ?

The approach is right if you are several other pages which are
completely different one with another
depends on the previous choices made in a previous page
Then you can add the next page dynamically (also as described here)
But if you have just a next page with a dynamic content, you should be able to create that content in the onEnterPage() method
public void createControl(Composite parent)
{
//
// create the composite to hold the widgets
//
this.composite = new Composite(parent, SWT.NONE);
//
// create the desired layout for this wizard page
//
GridLayout layout = new GridLayout();
layout.numColumns = 4;
this.composite.setLayout(layout);
// set the composite as the control for this page
setControl(this.composite);
}
void onEnterPage()
{
final MacroModel model = ((MacroWizard) getWizard()).model;
String selectedKey = model.selectedKey;
String[] attrs = (String[]) model.macroMap.get(selectedKey);
for (int i = 0; i < attrs.length; i++)
{
String attr = attrs[i];
Label label = new Label(this.composite, SWT.NONE);
label.setText(attr + ":");
new Text(this.composite, SWT.NONE);
}
pack();
}
As shown in the eclipse corner article Creating JFace Wizards:
We can change the order of the wizard pages by overwriting the getNextPage method of any wizard page.Before leaving the page, we save in the model the values chosen by the user. In our example, depending on the choice of travel the user will next see either the page with flights or the page for travelling by car.
public IWizardPage getNextPage(){
saveDataToModel();
if (planeButton.getSelection()) {
PlanePage page = ((HolidayWizard)getWizard()).planePage;
page.onEnterPage();
return page;
}
// Returns the next page depending on the selected button
if (carButton.getSelection()) {
return ((HolidayWizard)getWizard()).carPage;
}
return null;
}
We define a method to do this initialization for the PlanePage, onEnterPage() and we invoke this method when moving to the PlanePage, that is in the getNextPage() method for the first page.

If you want to start a new wizard based on your selection on the first page, you can use the JFace base class org.eclipse.jface.wizard.WizardSelectionPage.
The example below shows a list of available wizards defined by an extension point.
When you press Next, the selected wizard is started.
public class ModelSetupWizardSelectionPage extends WizardSelectionPage {
private ComboViewer providerViewer;
private IConfigurationElement selectedProvider;
public ModelSetupWizardSelectionPage(String pageName) {
super(pageName);
}
private class WizardNode implements IWizardNode {
private IWizard wizard = null;
private IConfigurationElement configurationElement;
public WizardNode(IConfigurationElement c) {
this.configurationElement = c;
}
#Override
public void dispose() {
}
#Override
public Point getExtent() {
return new Point(-1, -1);
}
#Override
public IWizard getWizard() {
if (wizard == null) {
try {
wizard = (IWizard) configurationElement
.createExecutableExtension("wizardClass");
} catch (CoreException e) {
}
}
return wizard;
}
#Override
public boolean isContentCreated() {
// TODO Auto-generated method stub
return wizard != null;
}
}
#Override
public void createControl(Composite parent) {
setTitle("Select model provider");
Composite main = new Composite(parent, SWT.NONE);
GridLayout gd = new GridLayout(2, false);
main.setLayout(gd);
new Label(main, SWT.NONE).setText("Model provider");
Combo providerList = new Combo(main, SWT.NONE);
providerViewer = new ComboViewer(providerList);
providerViewer.setLabelProvider(new LabelProvider() {
#Override
public String getText(Object element) {
if (element instanceof IConfigurationElement) {
IConfigurationElement c = (IConfigurationElement) element;
String result = c.getAttribute("name");
if (result == null || result.length() == 0) {
result = c.getAttribute("class");
}
return result;
}
return super.getText(element);
}
});
providerViewer
.addSelectionChangedListener(new ISelectionChangedListener() {
#Override
public void selectionChanged(SelectionChangedEvent event) {
ISelection selection = event.getSelection();
if (!selection.isEmpty()
&& selection instanceof IStructuredSelection) {
Object o = ((IStructuredSelection) selection)
.getFirstElement();
if (o instanceof IConfigurationElement) {
selectedProvider = (IConfigurationElement) o;
setMessage(selectedProvider.getAttribute("description"));
setSelectedNode(new WizardNode(selectedProvider));
}
}
}
});
providerViewer.setContentProvider(new ArrayContentProvider());
List<IConfigurationElement> providers = new ArrayList<IConfigurationElement>();
IExtensionRegistry registry = Platform.getExtensionRegistry();
IExtensionPoint extensionPoint = registry
.getExtensionPoint(<your extension point namespace>,<extension point name>);
if (extensionPoint != null) {
IExtension extensions[] = extensionPoint.getExtensions();
for (IExtension extension : extensions) {
IConfigurationElement configurationElements[] = extension
.getConfigurationElements();
for (IConfigurationElement c : configurationElements) {
providers.add(c);
}
}
}
providerViewer.setInput(providers);
setControl(main);
}
The corresponding wizard class looks like this:
public class ModelSetupWizard extends Wizard {
private ModelSetupWizardSelectionPage wizardSelectionPage;
public ModelSetupWizard() {
setForcePreviousAndNextButtons(true);
}
#Override
public boolean performFinish() {
// Do what you have to do to finish the wizard
return true;
}
#Override
public void addPages() {
wizardSelectionPage = new ModelSetupWizardSelectionPage("Select a wizard");
addPage(wizardSelectionPage);
}
}

Another alternative is to #Override setVisible. You can update page values or add additional widgets at that time.

I have a different solution.
If page depends on the result of page 1, create a variable and pass it into to first page, when that wizard page has the option from the user, then the last thing before the page is closed is to set the variable to the required value.
Then pass this variable to wizard, then pass it to the next wizard page. Then do a simple if statement and that way you get both choices together.
Remember that in most code there is only a small difference in the user options, so remember not to get bogged down in duplicating your code.