Develop Reference

Eclipse RCP - ToolItems not rendering with Edge browser until window resized

Hope you can help with a bit of a strange problem I'm having.
Take a very simple RCP application, with a toolbar along the top, where the user can switch between perspectives.
One perspective contains a Browser component.
Normally, when a user switches to the HelpDocumentsView, a browser is displayed and a bunch of red icons (highlighted) appear along the top.
But when using Edge webview2 as the browser component, using the following VM augments:
-Dorg.eclipse.swt.browser.DefaultType=edge -Dorg.eclipse.swt.browser.EdgeDir=path\to\Microsoft.WebView2.FixedVersionRuntime.103.0.1264.37.x64
The red icons are not displayed:
But when the application is resized, they appear:
Somehow the choice of browser rendering engine is changing how the ToolItems are being rendered, and I don't understand why.
I'm trying to use Edge because on Windows it'll use IE, and IE is unable to render the Javascript contained on the page I'd like to render in the browser.
PerspectiveSwitcherToolbar.java:
package com.me.rcp.perspective;
import javax.annotation.PostConstruct;
import javax.inject.Inject;
import org.eclipse.e4.ui.model.application.MApplication;
import org.eclipse.e4.ui.model.application.ui.advanced.MPerspective;
import org.eclipse.e4.ui.workbench.modeling.EModelService;
import org.eclipse.e4.ui.workbench.modeling.EPartService;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.layout.RowLayout;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Menu;
import org.eclipse.swt.widgets.MenuItem;
import org.eclipse.swt.widgets.ToolBar;
import org.eclipse.swt.widgets.ToolItem;
import org.osgi.service.event.Event;
import org.osgi.service.event.EventHandler;
import com.me.images.ImageProvider;
public class PerspectiveSwitcherToolbar implements EventHandler {
private static final String HELP_ID = "Help"; //$NON-NLS-1$
#Inject
private static MApplication app;
#Inject
private static EPartService partService;
#Inject
private static EModelService modelService;
private static ToolBar toolBar;
#PostConstruct
private static void postConstruct(final Composite parent) {
final Composite composite = new Composite(parent, SWT.NONE);
composite.setLayout(new RowLayout(SWT.HORIZONTAL));
toolBar = new ToolBar(composite, SWT.FLAT | SWT.WRAP | SWT.RIGHT);
parent.pack();
perspectiveSwitch("DataDashboard"); //$NON-NLS-1$
}
private static void perspectiveSwitch(final String id) {
final Menu switcherMenu = new Menu(toolBar);
final ToolItem choosePerspective = new ToolItem(toolBar, SWT.DROP_DOWN);
choosePerspective.setImage(ImageProvider.DATA_DASHBOARD);
choosePerspective.addSelectionListener(new SelectionAdapter() {
#Override
public void widgetSelected(final SelectionEvent e) {
final Rectangle rect = choosePerspective.getBounds();
final Point pt = switcherMenu.getParent().toDisplay(new Point(rect.x, rect.y));
switcherMenu.setLocation(pt.x, pt.y + rect.height);
switcherMenu.setVisible(true);
}
});
final MenuItem helpMenu = new MenuItem(switcherMenu, SWT.PUSH);
helpMenu.setImage(ImageProvider.HELP);
helpMenu.addSelectionListener(new SelectionAdapter() {
#Override
public void widgetSelected(final SelectionEvent e) {
perspectiveSwitch(HELP_ID);
}
});
partService.switchPerspective((MPerspective) modelService.find(id, app));
if (id.equals(HELP_ID)) {
for (int i = 0; i < 10; i++) {
new ToolItem(toolBar, SWT.PUSH).setImage(ImageProvider.USER_GUIDE);
}
}
}
#Override
public void handleEvent(final Event event) {
}
}
HelpDocumentsView.java:
package com.me.rcp.viewpart;
import javax.annotation.PostConstruct;
import org.eclipse.swt.SWT;
import org.eclipse.swt.browser.Browser;
import org.eclipse.swt.widgets.Composite;
public class HelpDocumentsView {
#PostConstruct
public void createPartControl(final Composite parent) {
new Browser(parent, SWT.NONE);
}
}

I think the problem is that the ToolItem doesn't have a text property set, only an image - and because of this one of the nested layout() calls is skipping it
When I set it to a zero-width space (e.g. item.setText("\u200B")) it renders correctly.

JavaFX Application Thread to Task Communication

I've been learning about JavaFX's Tasks and using these to communicate with the Application thread using Platform.runLater or the task's updateValue method etc. However, my Task needs to know when a user presses a button on the GUI as this could change the value needed to be returned by the Task's updateValue method. How do I go about doing this? I know how to respond to button press events on single threaded applications but am not sure how do deal with it in a thread-safe manner.
Update:
This is what I have so far, is this a sensible way of implementing the button event?
import javafx.application.Application;
import javafx.concurrent.Task;
import javafx.scene.Scene;
import javafx.stage.Stage;
import javafx.scene.canvas.Canvas;
import javafx.scene.canvas.GraphicsContext;
import javafx.scene.image.PixelWriter;
import javafx.scene.image.PixelFormat;
import javafx.scene.layout.Pane;
import javafx.scene.layout.VBox;
import javafx.scene.control.Button;
import java.nio.IntBuffer;
public class TaskExample extends Application {
private Canvas canvas;
private PixelWriter pixel_writer;
#Override
public void start(Stage primaryStage) throws Exception {
canvas = new Canvas(256, 256);
pixel_writer = canvas.getGraphicsContext2D().getPixelWriter();
MyTask task = new MyTask();
task.valueProperty().addListener((c) -> {
if(task.getValue() != null) {
update(task.getValue());
}
});
Thread thread = new Thread(task);
thread.setDaemon(true);
thread.start();
Button button = new Button("Button 1");
// On the button click event it calls the eventFired() method
button.setOnAction((event) -> {
task.eventFired();
});
Pane pane = new VBox();
pane.getChildren().addAll(canvas, button);
primaryStage.setScene(new Scene(pane));
primaryStage.show();
}
public void update(IntBuffer data) {
pixel_writer.setPixels(
0,
0,
256,
256,
PixelFormat.getIntArgbInstance(),
data,
256
);
}
public static void main(String[] args) {
launch(args);
}
class MyTask extends Task<IntBuffer> {
public void eventFired() {
System.out.println("Event fired");
}
public void update(IntBuffer data) {
updateValue(data);
}
#Override
protected IntBuffer call() throws InterruptedException {
while(true) {
for (int i=0; i<3; i++) {
Thread.sleep(1000);
IntBuffer data = IntBuffer.allocate(256*256);
for(int j=0; j<256*256; j++) {
switch(i) {
case 0: data.put(0xFF0000FF); break;
case 1: data.put(0xFF00FF00); break;
case 2: data.put(0xFFFF0000); break;
}
}
data.rewind();
update(data);
}
}
}
}
}

What I would do here is to think about ways to refactor what you are doing to avoid communication between two different threads. For example, instead of thinking of what you are doing as one long-running task that updates the UI as it progresses, think of it as a series of individual tasks that each update the UI when they complete. The ScheduledService class provides the machinery to manage these tasks and communicate between them and the FX Application Thread in a clean and safe way:
import java.nio.IntBuffer;
import java.util.Arrays;
import javafx.application.Application;
import javafx.concurrent.ScheduledService;
import javafx.concurrent.Task;
import javafx.scene.Scene;
import javafx.scene.canvas.Canvas;
import javafx.scene.control.Button;
import javafx.scene.image.PixelFormat;
import javafx.scene.image.PixelWriter;
import javafx.scene.layout.Pane;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;
import javafx.util.Duration;
public class TaskExample extends Application {
private Canvas canvas;
private PixelWriter pixel_writer;
#Override
public void start(Stage primaryStage) throws Exception {
canvas = new Canvas(256, 256);
pixel_writer = canvas.getGraphicsContext2D().getPixelWriter();
MyService service = new MyService();
service.setPeriod(Duration.seconds(1));
service.valueProperty().addListener((ols, oldData, newData) -> {
if(newData != null) {
update(newData);
}
});
service.start();
Button button = new Button("Button 1");
Pane pane = new VBox();
pane.getChildren().addAll(canvas, button);
primaryStage.setScene(new Scene(pane));
primaryStage.show();
}
public void update(IntBuffer data) {
pixel_writer.setPixels(
0,
0,
256,
256,
PixelFormat.getIntArgbInstance(),
data,
256
);
}
public static void main(String[] args) {
launch(args);
}
class MyService extends ScheduledService<IntBuffer> {
// both instance variables accessed only on FX Application Thread:
private final int[] colors = {0xFF0000FF, 0xFF00FF00, 0xFFFF0000} ;
private int count = -1 ;
#Override
protected Task<IntBuffer> createTask() {
// invoked on FX Application Thread
count = (count + 1) % colors.length ;
return new MyTask(colors[count]);
}
}
class MyTask extends Task<IntBuffer> {
private final int color ;
MyTask(int color) {
// invoked on FX Application Thread:
this.color = color ;
}
#Override
protected IntBuffer call() {
// invoked on background thread:
IntBuffer data = IntBuffer.allocate(256*256);
int[] a = new int[256*256];
Arrays.fill(a, color);
data.put(a, 0, a.length);
data.rewind();
return data ;
}
}
}
You haven't been very specific about how the UI is supposed to interact with the background thread, but if you wanted to change the behavior of the service when the button is pressed, you would now be changing the behavior of the createTask method, which is invoked on the FX Application Thread, instead of changing the behavior of a method already running on a different thread. This avoids any "low-level" concerns about synchronization.
For example:
class MyService extends ScheduledService<IntBuffer> {
// all instance variables accessed only on FX Application Thread:
private final int[][] colors = {
{0xFF0000FF, 0xFF00FF00, 0xFFFF0000},
{0xFF00FFFF, 0xFFFF00FF, 0xFFFFFF00}
};
private int count = -1 ;
private int scheme = 0 ;
#Override
protected Task<IntBuffer> createTask() {
// invoked on FX Application Thread
count = (count + 1) % colors[scheme].length ;
return new MyTask(colors[scheme][count]);
}
public void changeScheme() {
// invoked on FX Application Thread
scheme = (scheme + 1) % colors.length ;
}
}
and then just
button.setOnAction(e -> service.changeScheme());
Adding a call to service.restart(); here will force the change to happen as soon as possible:
button.setOnAction(e -> {
service.changeScheme();
service.restart();
});
There is pretty much always a way to refactor your code to take advantage of the library classes like this to avoid low-level communication between threads.

trayicon.displaymessage text size java

This is my first post in this forum and I really hope that it will be answered ASAP. I'm new to Java and loves trying different things often. I thought of making simple balloon message application in Java that pops up at certain time in the system tray conveying different message over time. Just wondering if I could change the text size of the balloon message. Also if somebody can help me out with time intervals and delays for the message to appear and disappear. Below is my code that I tried, please ponder a bit to help me out with this problem.
import java.awt.Image;
import java.awt.SystemTray;
import java.awt.TrayIcon;
import javax.swing.ImageIcon;
public class BubbleMessages {
public static void main(String[] args) throws Exception{
SystemTray tray = SystemTray.getSystemTray();
Image i = new ImageIcon("resources/bulb.gif").getImage();
TrayIcon ti = new TrayIcon(i);
tray.add(ti);
ti.displayMessage("Message", "message", TrayIcon.MessageType.INFO);
}
}

Check the api. The message will automatically disappear with a user click.
If you want to display the message again, you might use Timer
You can modify the code like this
import java.awt.Image;
import java.awt.SystemTray;
import java.awt.TrayIcon;
import javax.swing.ImageIcon;
public class BubbleMessages {
private static TrayIcon ti;
public static void main(String[] args) throws Exception{
SystemTray tray = SystemTray.getSystemTray();
Image i = new ImageIcon("resources/bulb.gif").getImage();
ti = new TrayIcon(i);
tray.add(ti);
MessageDisplayTask mdt = new MessageDisplayTask(ti);
java.util.Timer timer = new java.util.Timer("DM");
timer.schedule(mdt, 0, 10000);//Every three seconds, it shows a message
}
}
class MessageDisplayTask extends java.util.TimerTask {
private TrayIcon ti;
private int displayCount = 0;
public MessageDisplayTask(TrayIcon ti){
this.ti = ti;
}
public void run() {
displayCount++;
if (displayCount <= 10) {
ti.displayMessage("Message", "Message#" + displayCount, TrayIcon.MessageType.INFO);
} else {
//Stop Timer.
this.cancel();
}
}
}

tray.add(ti);
ti.setImageAutoSize(true);
ti.displayMessage("Message", "message", TrayIcon.MessageType.INFO);

How can I convert a swing JTextField component in to an object of a type that extends it

I have an application using a third party package that has a factory that returns to me JTextField objects that are then added to a GUI. This makes up about 10% of the JTextFields used.
I can't change the third party package but have a requirement to add right click (cut, copy and paste) options in to all ofthe fields.
Now I have a RightClickTextField that extends JTextField and has all the functionality built in to it, this serves to solve my issue for 90% of the application.
However for the 10% that's using the third party package to get JTextFields I cannot think of a solution that will allow me to declare the fields as RightClickTextFields yet use the factory I have to get back the Boxes. I know I cannot cast the result as the objects returned are not of a type that high up in the hierarchy, and a copy constructor won't work since I cannot copy every property being set by the factory, but I don't know of a way to upcast the JTextField in to my type. Is there one?

Rather than subclassing or trying to cast it, can you put your right-click functionality into its own class which implements the MouseInputListener interface, and simply add an instance of your right-click handler to the JTextField objects in question?

Maybe use the Decorator Pattern. This way you can stop using RightClickTextField at all - start using RightClickTextFieldDecorator and supply it either with your own JTextFields or the ones you get from 3rd party thingy.

Thanks for all the comments. I think the actual answer to my question is:
You can't.
Whilst all of the suggestions are valid, I knew it was possible to do all those things, I just wanted to know if I could do it my way first.
My solution (based on feedback here and my own preference) was to create this class below, and manage and expose a single instance of it from a singleton.
I'd appreciate thoughts on this solution?
import java.awt.Component;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.util.HashMap;
import java.util.Map;
import javax.swing.JMenuItem;
import javax.swing.JPopupMenu;
import javax.swing.text.JTextComponent;
public class CopyPasteTextComponentPopoupMenu extends JPopupMenu implements
ActionListener {
private JTextComponent lastInvoker;
private JMenuItem cutMenuItem;
private JMenuItem copyMenuItem;
private JMenuItem pasteMenuItem;
private Map<JTextComponent, JTCProperties> managedComponents;
private MouseListener heyListen;
public CopyPasteTextComponentPopoupMenu() {
super();
init();
}
public CopyPasteTextComponentPopoupMenu(String label) {
super(label);
init();
}
#Override
public void show(Component invoker, int x, int y) {
JTCProperties props = managedComponents.get(invoker);
if(props!=null) {
this.lastInvoker = (JTextComponent) invoker;
setEnabled(props);
super.show(invoker, x, y);
} else {
this.lastInvoker = null;
}
}
public void manageTextComponent(JTextComponent jtc, boolean canCut,
boolean canCopy, boolean canPaste) {
jtc.addMouseListener(heyListen);
JTCProperties props = new JTCProperties(canCut,canCopy,canPaste);
managedComponents.put(jtc,props);
}
public void dispose() {
for (JTextComponent component : managedComponents.keySet()) {
component.removeMouseListener(heyListen);
managedComponents.remove(component);
}
}
#Override
public void actionPerformed(ActionEvent e) {
if (lastInvoker != null) {
if (e.getSource() == cutMenuItem) {
lastInvoker.cut();
} else if (e.getSource() == copyMenuItem) {
lastInvoker.copy();
} else if (e.getSource() == pasteMenuItem) {
lastInvoker.paste();
}
}
}
private void setEnabled(JTCProperties props) {
cutMenuItem.setEnabled(props.canCut);
copyMenuItem.setEnabled(props.canCopy);
pasteMenuItem.setEnabled(props.canPaste);
}
private void init() {
this.managedComponents = new HashMap<JTextComponent, JTCProperties>();
this.setPreferredSize(new Dimension(100, 70));
cutMenuItem = new JMenuItem("Cut");
copyMenuItem = new JMenuItem("Copy");
pasteMenuItem = new JMenuItem("Paste");
cutMenuItem.addActionListener(this);
copyMenuItem.addActionListener(this);
pasteMenuItem.addActionListener(this);
this.add(cutMenuItem);
this.add(copyMenuItem);
this.add(pasteMenuItem);
heyListen = new MouseAdapter() {
public void mousePressed(MouseEvent e) {
if (e.isPopupTrigger()) {
show(e.getComponent(), e.getX(), e.getY());
}
}
public void mouseReleased(MouseEvent e) {
if (e.isPopupTrigger()) {
show(e.getComponent(), e.getX(), e.getY());
}
}
};
}
private class JTCProperties {
public boolean canCut, canCopy, canPaste;
public JTCProperties(boolean canCut, boolean canCopy, boolean canPaste) {
this.canCut = canCut;
this.canCopy = canCopy;
this.canPaste = canPaste;
}
}
}

VLCJ: Updating the progress bar as the video progresses

Please have a look at the following code
import com.sun.jna.Native;
import uk.co.caprica.vlcj.binding.LibVlc;
import uk.co.caprica.vlcj.component.EmbeddedMediaPlayerComponent;
import uk.co.caprica.vlcj.runtime.RuntimeUtil;
import com.sun.jna.NativeLibrary;
import javax.swing.JFrame;
import javax.swing.SwingUtilities;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import javax.media.bean.playerbean.MediaPlayer;
import uk.co.caprica.vlcj.player.MediaPlayerEventAdapter;
import uk.co.caprica.vlcj.player.MediaPlayerEventListener;
public class PlayMedia extends JFrame
{
private EmbeddedMediaPlayerComponent m;
private JProgressBar bar;
public PlayMedia()
{
NativeLibrary.addSearchPath(
RuntimeUtil.getLibVlcLibraryName(), "c:\\program files\\videolan\\vlc"
);
Native.loadLibrary(RuntimeUtil.getLibVlcLibraryName(), LibVlc.class);
m = new EmbeddedMediaPlayerComponent();
m.getMediaPlayer().addMediaPlayerEventListener(new UpdateBar());
bar = new JProgressBar(0,100);
bar.setStringPainted(true);
getContentPane().add(m);
getContentPane().add(bar,"South");
this.setSize(500,500);
this.validate();
this.setLocationRelativeTo(null);
this.setVisible(true);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
m.getMediaPlayer().playMedia("C:\\Users\\Yohan\\Desktop\\video.avi");
}
private class UpdateBar extends MediaPlayerEventAdapter
{
public void positionChanged(MediaPlayer mp, float pos)
{
int value = Math.min(100, Math.round(pos * 100.0f));
bar.setValue(value);
}
}
public static void main(String[]args)
{
SwingUtilities.invokeLater(new Runnable()
{
#Override
public void run()
{
new PlayMedia();
}
});
}
}
In here, video is playing fine, but the progress bar is not getting updated. How to update the progress bar as the video plays? Please help!

I haven't used ProgressBars in Swing, but I have used them in Silverlight, so I would think most of the principles would be the same. Check out the answer to my question here:
How do I make a Silverlight Progressbar update according to its value? It may not show you exactly how to do this in Swing, but it doesn't seem like you're using threading in your code, which is what my problem was.

for some unknown reason positionChanged() isn't called during the video.
try to use timeChanged() istead, it worked for me!
public void positionChanged (MediaPlayer mediaPlayer , long time) { ... }