I am trying to get my Blackberry application to display a custom modal dialog, and have the opening thread wait until the user closes the dialog screen.
final Screen dialog = new FullScreen();
...// Fields are added to dialog
Application.getApplication().invokeAndWait(new Runnable()
{
public void run()
{
Application.getUiApplication().pushModalScreen(dialog);
}
});
This is throwing an Exception which says "pushModalScreen called by a non-event thread" despite the fact that I am using invokeAndWait to call pushModalScreen from the event thread.
Any ideas about what the real problem is?
Here is the code to duplicate this problem:
package com.test;
import net.rim.device.api.ui.*;
import net.rim.device.api.ui.component.*;
import net.rim.device.api.ui.container.*;
public class Application extends UiApplication {
public static void main(String[] args)
{
new Application();
}
private Application()
{
new Thread()
{
public void run()
{
Application.this.enterEventDispatcher();
}
}.start();
final Screen dialog = new FullScreen();
final ButtonField closeButton = new ButtonField("Close Dialog");
closeButton.setChangeListener(new FieldChangeListener()
{
public void fieldChanged(Field field, int context)
{
Application.getUiApplication().popScreen(dialog);
}
});
dialog.add(closeButton);
Application.getApplication().invokeAndWait(new Runnable()
{
public void run()
{
try
{
Application.getUiApplication().pushModalScreen(dialog);
}
catch (Exception e)
{
// To see the Exception in the debugger
throw new RuntimeException(e.getMessage());
}
}
});
System.exit(0);
}
}
I am using Component Package version 4.5.0.
Building on Max Gontar's observation that the Exception is not thrown when using invokeLater instead of invokeAndWait, the full solution is to implement invokeAndWait correctly out of invokeLater and Java's synchronization methods:
public static void invokeAndWait(final Application application,
final Runnable runnable)
{
final Object syncEvent = new Object();
synchronized(syncEvent)
{
application.invokeLater(new Runnable()
{
public void run()
{
runnable.run();
synchronized(syncEvent)
{
syncEvent.notify();
}
}
});
try
{
syncEvent.wait();
}
catch (InterruptedException e)
{
// This should not happen
throw new RuntimeException(e.getMessage());
}
}
}
Unfortunately, the invokeAndWait method cannot be overridden, so care must be used to call this static version instead.
Seems as though there's a bunch of code in there that's unnecessary.
public class Application extends UiApplication {
public static void main(String[] args)
{
new Application().enterEventDispatcher();
}
private Application()
{
final Screen dialog = new FullScreen();
final ButtonField closeButton = new ButtonField("Close Dialog");
closeButton.setChangeListener(new FieldChangeListener()
{
public void fieldChanged(Field field, int context)
{
Application.getUiApplication().popScreen(dialog);
}
});
dialog.add(closeButton);
// this call will block the current event thread
pushModalScreen(dialog);
System.exit(0);
}
}
Use this:
UiApplication.getUiApplication().invokeAndWait(new Runnable() {
public void run() {
pushScreen(new MyScreen());
}
});
Related
I'm trying to restart spring boot application after executing an application.
So I've added a context in the main class:
#SpringBootApplication
public class MainApplication {
private static ConfigurableApplicationContext context;
public static void main(String[] args) { context = SpringApplication.run(MainApplication.class, args); }
public static void restart() {
ApplicationArguments args = context.getBean(ApplicationArguments.class);
Thread thread = new Thread(() -> {
context.close();
context = SpringApplication.run(MainApplication.class, args.getSourceArgs());
});
thread.setDaemon(false);
thread.start();
}
}
To call the restart method, Here is the Service:
#EventListener(ApplicationReadyEvent.class)
#Transactional
public void saveMaths() {
int maths = 0;
List<User> users;
try {
users = userRepository.findByMathsWhereNull();
for (User user : users) {
maths = calculateMaths(user);
user.setMaths(maths);
userRepository.updateUser(maths, user.getId());
}
} finally {
restart();
}
}
public void restart() {
Application.restart();
}
But unfortunatelly, if the principal method works, I've a null pointer exception in the finally restart().
I've instanciated maths and users list just to be sure and once again, this method works. What did I do wrong?
I'm trying to handle exceptions with AOP approach in my Spring/Swing Application and I couldn't make it work.
Main Class:
public class MainFrame extends JFrame {
private JPanel mainPanel;
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
MainFrame frame = new MainFrame();
frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
public MainFrame() {
initializeMainPanel();
}
private void initializeMainPanel() {
exitLabel.addMouseListener(new MouseAdapter() {
#Override
public void mouseClicked(MouseEvent arg0) {
throw new Exception("test");
}
});
}
}
Aspect Class:
#Aspect
public class AspectTest{
#AfterThrowing(pointcut = "execution(* com.test.MainFrame.*(..))", throwing = "ex")
public void logError(Exception ex) throws Throwable {
// ex.printStackTrace();
}
}
So, I throw an exception within my Mouse Listener and expect to catch it in my AspectTest class' AfterThrowing method but it does not work.
Can someone please help me to understand what I'm missing here?
#AfterThrowing cannot catch exceptions, only notice them and log them or do something similar. If you want to handle exceptions in an aspect you need to use an #Around advice.
I need to update my GUI based on client input. Calling my controller class method, from the background task works. But it can't update the GUI, because it is not the JavaFX application thread..please help.
I tried many of the related Q & A, but I am still confused.
Should I use Platform. runLater or Task ?
Here's my class where I create an instance of controller class
public class FactoryClass {
public static Controller_Gui1 createGUI() {
FXMLLoader fxLoader = new FXMLLoader();
fxLoader.setLocation(MainApp_Gui1.class.getResource("/com/Gui_1.fxml"));
AnchorPane anchorPane = null;
try {
anchorPane = (AnchorPane) fxLoader.load();
} catch (IOException e) {
e.printStackTrace();
}
Controller_Gui1 controller_Gui1 = (Controller_Gui1) fxLoader
.getController();
Scene scene = new Scene(anchorPane);
//System.out.println(scene);
controller_Gui1.setScene(scene);
return controller_Gui1;
}
}
Controller class
#FXML
Button B1 = new Button();
#FXML
public void handleButton1() {
B1.setDisable(true);
}
Application class
public class MainApp_Gui1 extends Application {
Controller_Gui1 cGui;
#Override
public void start(Stage primaryStage) throws Exception {
initScene(primaryStage);
primaryStage.show();
System.out.println("asdasd");
SceneSetting sceneSetting = new SceneSetting();
//handleEvent();
System.out.println("after");
sceneSetting.setSceneAfter();
System.out.println("after2");
}
// creating scene
private void initScene(Stage primaryStage) throws IOException {
primaryStage.setScene(getScene(primaryStage));
}
public Scene getScene(Stage primaryStage) {
Controller_Gui1 cGui;
cGui = FactoryClass.createGUI();
return cGui.getScene();
}
public void ExcessFromOutside() {
Platform.runLater(new Runnable() {
public void run() {
System.out.println(Platform.isFxApplicationThread());
cGui.handleButton1();
}
});
}
public static void main(String[] args) {
launch(args);
}
}
I want to call ExcessFromOutside() method from another thread.
I got a null pointer exception while trying to update the GUI
Here's my application class
public class MainAppGui1 extends Application {
Controller_Gui1 controller_Gui1;
#Override
public void start(Stage primaryStage) throws Exception {
initScene(primaryStage);
primaryStage.show();
}
// creating scene
public void initScene(Stage primaryStage) throws IOException {
FXMLLoader fxLoader = new FXMLLoader();
fxLoader.setLocation(MainApp_Gui1.class.getResource("/com/Gui_1.fxml"));
AnchorPane anchorPane=new AnchorPane();
anchorPane = (AnchorPane) fxLoader.load();
Controller_Gui1 controller_Gui1 = (Controller_Gui1) fxLoader.getController();
Scene scene = new Scene(anchorPane);
primaryStage.setScene(scene);
}
#FXML
public void ExcessFromOutside()
{
Platform.runLater(new Runnable() {
#Override
public void run() {
System.out.println("called atleast");
controller_Gui1.handleButton1();
}
});
}
public static void main(String[] args) {
launch(args);
}
}
and this is the class from where i tried to update the GUI
public class Hudai {
public static void main(String args[]) throws InterruptedException
{
new Thread()
{
public void run()
{
MainAppGui1.main(null);
}
}.start();
Thread.sleep(5000);
MainAppGui1 m = new MainAppGui1();
m.ExcessFromOutside();
}
}
To disable your button in a different thread you can use Task's updateValue.
Task<Boolean> task = new Task<Boolean>() {
#Override
public Boolean call() {
... // The task that this thread needs to do
updateValue(true);
...
return null;
}
};
button.disableProperty().bind(task.valueProperty());
If you want to use a new thread to call a method, which alters the scene graph, the best chance you have is to use Platform.runLater() in it.
//code inside Thread
...
// code to run on the JavaFX Application thread
Platform.runLater(new Runnable() {
#Override
public void run() {
handleButton1();
}
});
...
You should get a NullPointerException when you run this program.
The problem is, the member of MainApp_Gui1
Controller_Gui1 cGui;
never gets a value.
Remove line "Controller_Gui1 cGui;" from this code:
public Scene getScene(Stage primaryStage) {
// Hudai hudai = new Hudai(primaryStage);
// return hudai.getScene();
Controller_Gui1 cGui;
cGui = FactoryClass.createGUI();
return cGui.getScene();
}
public class MainActivity extends Activity {
TextView statustv = (TextView) findViewById(R.id.status);;
ProgressDialog pd;
String status, url = "http://wvde.state.wv.us/closings/county/monongalia";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
new School().execute();
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
private class School extends AsyncTask<Void, Void, Void> {
#Override
protected void onPreExecute() {
super.onPreExecute();
pd = new ProgressDialog(MainActivity.this);
pd.setTitle("Android Basic JSoup Tutorial");
pd.setMessage("Loading...");
pd.setIndeterminate(false);
pd.show();
}
#Override
protected Void doInBackground(Void... params) {
try {
Document doc = Jsoup.connect(url).get();
Elements table = doc.select("td#content_body");
status = table.select("table").text();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(Void result) {
statustv.setText(status);
pd.dismiss();
}
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == R.id.action_refresh) {
new School().execute();
return true;
}
return super.onOptionsItemSelected(item);
}
}
How can I have new School().execute(); happen oncreate without getting a nullpointer error because right now when oncreate executes it executes new School().execute(); before it even knows what the asynchtask is. How can i have it execute correctly oncreate?
You can post a runnable to the current thread's handler. The runnable starts the AsyncTask.
Here is an easy example of using handler: https://stackoverflow.com/a/1921759/1843698
Official Doc for Handler: http://developer.android.com/reference/android/os/Handler.html
The handler schedule a task (your runnable) in current thread, and your task will be executed later in the same thread as soon as possible, but it will be executed after onCreate() finishes.
I am trying to create a GUI interface to start and stop a Jetty server with different return strings. Currently I have a start and stop button programmed and it returns "Hello World" into localhost:8080. My code is posted below, yes I have imports, removed to simplify it.
public class JettyGUI extends AbstractHandler{
private static Server server = new Server(8080);
private static boolean running = false;
private static void gui() {
JFrame frame = new JFrame("Jetty");
JButton start_button = new JButton("Start");
JButton stop_button = new JButton("Stop");
JPanel panel = new JPanel();
panel.setBackground(Color.BLACK);
panel.add(start_button);
panel.add(stop_button);
frame.add(panel);
frame.setSize(300, 150);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
start_button.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.out.println("Start pressed.");
startServer();
}
});
stop_button.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.out.println("Stop pressed.");
JettyGUI.stopServer();
}
});
}
private static void stopServer() {
if(running == false){
System.err.println("Server is already running!");
}
else{
try {
server.stop();
}
catch (Exception ex) {
System.out.println(ex);
}
}
System.out.println("Server stopped!");
}
private static void startServer() {
if(running == true){
System.err.println("Server is already running!");
}
else{
try{
server.setHandler(new JettyGUI());
server.start();
server.join();
}
catch(Exception ex){
System.out.println(ex);
}
System.out.println("Server started!");
}
}
public void handle(String target, Request baseRequest, HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {
response.setContentType("text;charset=utf-8");
response.setStatus(HttpServletResponse.SC_OK);
baseRequest.setHandled(true);
response.getWriter().println("Hello World!"); //print this text
}
public static void main(String[] args) {
gui();
}
}
When I press the "start" button, Jetty API seems to take over my application and I can no longer press the "stop" button. Could anyone tell me a way to navigate around this or program this differently?
Thanks! :)
-Henry Harris
The server.join(); will make the current thread wait until the server is stopped.
Comment it out, as a GUI program you don't need it.