NullPointerException when I'm trying to read a resource - gluon

Question

I have a Gluon Mobile JavafX project.
I'm trying to read a resource from my apk and I'm receiving an error only in Android.
private void leerConfiguracion() { logger.log(Level.INFO, "ConfiguradorGeneralService:leerConfiguracion: BEGIN ... ");
try
{
File fileLugares = new File(ConfiguradorGeneralService.class.getResource("/com/registrodevisitas/json/configuracion.json").getFile());
logger.log(Level.INFO, "ConfiguradorGeneralService:leerConfiguracion: Leyendo configuración: " + fileLugares.getAbsolutePath());
// create a FileClient to the specified File
FileClient fileClient = FileClient.create(fileLugares);
// create a JSON converter that converts the nodes from a JSON array into language objects
InputStreamIterableInputConverter<ConfiguradorGeneral> converter = new JsonIterableInputConverter<>(ConfiguradorGeneral.class);
// retrieve a list from a ListDataReader created from the FileClient
configuracion = DataProvider.retrieveList(fileClient.createListDataReader(converter));
}
catch(Exception e)
{
logger.log(Level.SEVERE, e.getMessage(), e);
}
logger.log(Level.INFO, "ConfiguradorGeneralService:leerConfiguracion: END ");
}
The error on Android is:
I/figuradorGeneralService(11481): ConfiguradorGeneralService:leerConfiguracion: BEGIN ...
E/figuradorGeneralService(11481): null
E/figuradorGeneralService(11481): java.lang.NullPointerException
E/figuradorGeneralService(11481): at com.registrodevisitas.services.ConfiguradorGeneralService.leerConfiguracion(ConfiguradorGeneralService.java:50)
E/figuradorGeneralService(11481): at com.registrodevisitas.services.ConfiguradorGeneralService.<init>(ConfiguradorGeneralService.java:34)
E/figuradorGeneralService(11481): at java.lang.Class.newInstanceImpl(Native Method)
E/figuradorGeneralService(11481): at java.lang.Class.newInstance(Class.java:1208)
E/figuradorGeneralService(11481): at com.airhacks.afterburner.injection.Injector.lambda$getDefaultInstanceSupplier$8(Injector.java:233)
E/figuradorGeneralService(11481): at com.airhacks.afterburner.injection.Injector.access$lambda$3(Injector.java)
E/figuradorGeneralService(11481): at com.airhacks.afterburner.injection.Injector$$Lambda$4.apply(Unknown Source)
E/figuradorGeneralService(11481): at com.airhacks.afterburner.injection.Injector.instantiateModelOrService(Injector.java:116)
E/figuradorGeneralService(11481): at com.airhacks.afterburner.injection.Injector.injectMembers(Injector.java:151)
E/figuradorGeneralService(11481): at com.airhacks.afterburner.injection.Injector.injectMembers(Injector.java:136)
E/figuradorGeneralService(11481): at com.airhacks.afterburner.injection.Injector.injectAndInitialize(Injector.java:129)
E/figuradorGeneralService(11481): at com.airhacks.afterburner.injection.Injector.registerExistingAndInject(Injector.java:107)
E/figuradorGeneralService(11481): at com.airhacks.afterburner.injection.Injector.instantiatePresenter(Injector.java:60)
E/figuradorGeneralService(11481): at com.airhacks.afterburner.views.FXMLView.lambda$loadSynchronously$2(FXMLView.java:89)
E/figuradorGeneralService(11481): at com.airhacks.afterburner.views.FXMLView.access$lambda$1(FXMLView.java)
E/figuradorGeneralService(11481): at com.airhacks.afterburner.views.FXMLView$$Lambda$2.call(Unknown Source)
E/figuradorGeneralService(11481): at javafx.fxml.FXMLLoader$ValueElement.processAttribute(FXMLLoader.java:929)
E/figuradorGeneralService(11481): at javafx.fxml.FXMLLoader$InstanceDeclarationElement.processAttribute(FXMLLoader.java:971)
E/figuradorGeneralService(11481): at javafx.fxml.FXMLLoader$Element.processStartElement(FXMLLoader.java:220)
E/figuradorGeneralService(11481): at javafx.fxml.FXMLLoader$ValueElement.processStartElement(FXMLLoader.java:744)
E/figuradorGeneralService(11481): at javafx.fxml.FXMLLoader.processStartElement(FXMLLoader.java:2707)
E/figuradorGeneralService(11481): at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2527)
E/figuradorGeneralService(11481): at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2441)
E/figuradorGeneralService(11481): at javafx.fxml.FXMLLoader.load(FXMLLoader.java:2409)
E/figuradorGeneralService(11481): at com.airhacks.afterburner.views.FXMLView.loadSynchronously(FXMLView.java:91)
E/figuradorGeneralService(11481): at com.airhacks.afterburner.views.FXMLView.initializeFXMLLoader(FXMLView.java:100)
E/figuradorGeneralService(11481): at com.airhacks.afterburner.views.FXMLView.getView(FXMLView.java:112)
E/figuradorGeneralService(11481): at com.registrodevisitas.RegistroDeVisitas.lambda$init$0(RegistroDeVisitas.java:55)
E/figuradorGeneralService(11481): at com.registrodevisitas.RegistroDeVisitas.access$lambda$0(RegistroDeVisitas.java)
E/figuradorGeneralService(11481): at com.registrodevisitas.RegistroDeVisitas$$Lambda$1.get(Unknown Source)
E/figuradorGeneralService(11481): at com.gluonhq.impl.charm.a.d.a.a(SourceFile:32)
E/figuradorGeneralService(11481): at com.gluonhq.charm.glisten.application.MobileApplication.a(SourceFile:620)
E/figuradorGeneralService(11481): at com.gluonhq.charm.glisten.application.MobileApplication.switchView(SourceFile:391)
E/figuradorGeneralService(11481): at com.gluonhq.charm.glisten.application.MobileApplication.switchView(SourceFile:368)
E/figuradorGeneralService(11481): at com.gluonhq.charm.glisten.application.MobileApplication.start(SourceFile:218)
E/figuradorGeneralService(11481): at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$144(LauncherImpl.java:863)
E/figuradorGeneralService(11481): at com.sun.javafx.application.LauncherImpl.access$lambda$8(LauncherImpl.java)
E/figuradorGeneralService(11481): at com.sun.javafx.application.LauncherImpl$$Lambda$9.run(Unknown Source)
E/figuradorGeneralService(11481): at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$157(PlatformImpl.java:326)
E/figuradorGeneralService(11481): at com.sun.javafx.application.PlatformImpl.access$lambda$6(PlatformImpl.java)
E/figuradorGeneralService(11481): at com.sun.javafx.application.PlatformImpl$$Lambda$7.run(Unknown Source)
E/figuradorGeneralService(11481): at com.sun.javafx.application.PlatformImpl.lambda$null$155(PlatformImpl.java:295)
E/figuradorGeneralService(11481): at com.sun.javafx.application.PlatformImpl.access$lambda$18(PlatformImpl.java)
E/figuradorGeneralService(11481): at com.sun.javafx.application.PlatformImpl$$Lambda$19.run(Unknown Source)
E/figuradorGeneralService(11481): at java.security.AccessController.doPrivileged(AccessController.java:52)
E/figuradorGeneralService(11481): at com.sun.javafx.application.PlatformImpl.lambda$runLater$156(PlatformImpl.java:294)
E/figuradorGeneralService(11481): at com.sun.javafx.application.PlatformImpl.access$lambda$5(PlatformImpl.java)
E/figuradorGeneralService(11481): at com.sun.javafx.application.PlatformImpl$$Lambda$6.run(Unknown Source)
E/figuradorGeneralService(11481): at com.sun.glass.ui.monocle.RunnableProcessor.runLoop(RunnableProcessor.java:92)
E/figuradorGeneralService(11481): at com.sun.glass.ui.monocle.RunnableProcessor.run(RunnableProcessor.java:51)
E/figuradorGeneralService(11481): at java.lang.Thread.run(Thread.java:8
I/figuradorGeneralService(11481): ConfiguradorGeneralService:leerConfiguracion: END
This file is on RESOURCE/COM....
This method is working perfectly on windows.
Any help would be nice. Thank you.

Answer 1

On Android (and iOS), you can't directly access classpath resources as a File, like you can on desktop. Instead, you need to access resources by using the InputStream. This works on all the supported platforms (android, iOS and desktop).
Try to access your resource with the following code:
BasicInputDataSource source = new BasicInputDataSource(ConfiguradorGeneralService.class.getResourceAsStream("/com/registrodevisitas/json/configuracion.json"));
InputStreamIterableInputConverter<ConfiguradorGeneral> converter = new JsonIterableInputConverter<>(ConfiguradorGeneral.class);
configuracion = DataProvider.retrieveList(new InputStreamListDataReader<>(source, converter));