Develop Reference

How to add a seekbar to a video played using vlcj in Java Swing?

I’ve trimmed down the code to only the relevant parts and posted it below. The code works fine. The video plays when you run it but it doesn’t have a seekbar.
public class Screen {
//JFrmae
private JFrame frame;
// Panel which I add the canvas to
private JPanel pVid = new JPanel();
// Canvas
Canvas canvas = new Canvas();
// Embedded Media Player
EmbeddedMediaPlayer emp;
/**
* Create the application.
*/
public Screen() {
initialize();
}
/**
* Initialize the contents of the frame.
*/
private void initialize() {
//Frame
frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
//Adding the panel to the frame
frame.getContentPane().add(pVid);
//Adding the canvas to the panel
pVid.add(canvas);
//Setting canvas size
canvas.setSize(715, 402);
//Loading the VLC native library
NativeLibrary.addSearchPath(RuntimeUtil.getLibVlcLibraryName(), "lib");
Native.loadLibrary(RuntimeUtil.getLibVlcLibraryName(), LibVlc.class);
//Initializing the media player
MediaPlayerFactory mpf = new MediaPlayerFactory();
//Misc
emp = mpf.newEmbeddedMediaPlayer(new Win32FullScreenStrategy(frame));
emp.setVideoSurface(mpf.newVideoSurface(canvas));
//Video file name and playing
String file = "video.mp4";
emp.prepareMedia(file);
emp.play();
//pack method
frame.pack();
}
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
Screen window = new Screen();
window.frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
}
I’ve looked for an answer online for the last 4 days. Finally I decided to ask here. The official website for vlcj has pictures of a vlcj player they’ve made. There is a seekbar in those pictures. Link to the webpage which has the pics: http://capricasoftware.co.uk/#/projects/vlcj
They have a number of useful tutorials there but they don’t have any instructions for adding the seekbar.
Then I tried downloading their vlcj-player project from their GitHub page. It showed an error because it couldn’t resolve the “com.google.common.collect.ImmutableList” which is supposed to be imported. (At the moment I’m reading about ImmutableList and stuff and see if there’s a way to fix it.) Since I couldn’t figure that out yet, I looked for a class named seekbar or the like in their project. I couldn’t find any.
I also searched elsewhere online for the answer but I just couldn’t find it. I’d really appreciate any help. Thank you.
Edit:
(This edit is in response to the suggestion given to me by #caprica. Read their comment to this question and my reply to that in the comment to understand what I'm talking about here in this edit. I think it'll be useful for others in the future.)
All right, there must have been some problem with my Eclipse or computer. (I’ll type out how I fixed it at the end of this comment.) It’s working now. I’ll type out what I did step by step so that may be it’ll be useful to others in the future to download and install the project.
Download the project.
Import it as a Maven project. (Import > Maven > Existing Maven Project)
Now in Eclipse right click the imported project and select Run As > Maven Install
And that’s it. Now you can just run the project normally. If you don’t know how to run the project, do it like this. Right click the project and select Run As > Java Application and then Select VlcjPlayer – uk.co.caprica.vlcplayer.
Alternatively you can open the class where the main method is and run it. VlcjPlayer class is where the main method is located. The class is in the package uk.co.caprica.vlcplayer.
The problem I faced was that somehow all the necessary files didn’t get downloaded when I ran it as Maven Install. But it worked fine in another computer. Since I knew where the files are downloaded to, I just copied the folder from that PC and put it in the same place in my PC. The folder name is ‘repository’. It’s location is C:\Users\User Name\ .m2. Perhaps Eclipse in this PC has some problem. I’ll reinstall it later to avoid problems in the future.
And this may be useful, the VLC that’s installed in this PC is 64 bit. Not sure if that makes a difference but mentioning it just in case.
Now that the app is working fine I will see the code and see how the seekbar is made. Thanks a lot #caprica for telling me that I should import it as a Maven project. :)

The Basic Controls tutorial shows the essential approach: Add a panel of buttons to the frame and give each button an ActionListener that invokes the relevant media player command. As an example, this notional Rewind button would "skip backwards 10 seconds (-10,000 milliseconds)."
JPanel controlsPane = new JPanel();
JButton rewindButton = new JButton("Rewind");
rewindButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
mediaPlayerComponent.getMediaPlayer().skip(-10000);
}
});
controlsPane.add(rewindButton);
frame.add(controlsPane, BorderLayout.SOUTH);
The software design is up to you, but you should at least be aware of
JToolBar, seen here and here.
Action, seen here and cited here.
Timer, seen here as a way to repeat an Action.

All right, guys. I’ve figured out how to do it. I’m not sure how it was done in the official Vlcj project but I’ve figured out my own simple way by learning from the official project.
It just takes a few lines of code. It’s very simple.
These are the steps you have to follow:
Create a JSlider.
To the JSlider, add a mouseMotionListener (‘mouseDragged’ to be exact).
Inside that put in the code which would update the video position based on
the change in the JSlider.
Create a Timer.
Put the code inside it to set the value of the JSlider based on the position
of the video.
And that’s it!
This is the code. It comes inside the initialize() method which you can see in the code I’ve given in the question. (And of course you'll also have to create the JSlider and add it to the panel. I haven't shown the code since it's simple.)
js.addMouseMotionListener(new MouseMotionAdapter() {
#Override
public void mouseDragged(MouseEvent e) {
if (js.getValue() / 100 < 1) {
emp.setPosition((float) js.getValue() / 100);
}
}
});
Timer timer = new Timer(100, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
js.setValue(Math.round(emp.getPosition() * 100));
}
});
timer.start();
Some explanation.
The value you get when you use emp.getPosition always seems to be in decimals. It’s something like 0.1334344 at the start of the video and it’s something like 0.998988 at the end. But the value of JSlider is in int. From 0 to 100. So in the mouseMotionListener added to the JSlider I’ve converted the int value of the JSlider to float by dividing it by 100.
And in the action listener inside the timer I’ve multiplied the value of the video position by 100 and then rounded it off to make it an int value. So that value can be set in the JSlider to make it move in sync with the video.
I’m sure the code is rudimentary and there could be some best practices which I may not have followed. Sorry about that but I’m just getting into java by learning the stuff which I find interesting. Those who are good at java and have used such code in an actual project can comment below with how it can be improved.

Java JOptionPane Visual Artifact from Window Interaction

I am trying to create a simple menu for a small project using a JSpinner and JOptionPane. I created my desired output, but when I interact with the window or even hover over the buttons in the box, it creates visual artifacts over and over again (see images below):
JOptionPane before mouse hover
JOptionPane after mouse hover
I did some researching and thought it might be due to JOptionPane not being thread safe, but could not get anything to work.
Overall, my specific question is how do I prevent Java from repainting these visual artifacts over my JOptionPane window?
For reference, please see the method I am using to show this menu:
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.SpinnerNumberModel;
import javax.swing.JSpinner;
public class Battleship
{
public static void main(String[] args)
{
SpinnerNumberModel battleshipRange = new SpinnerNumberModel(1, 1, 5, 1);
JSpinner rangeSpinner = new JSpinner(battleshipRange);
JOptionPane.showMessageDialog(null, rangeSpinner, "Battleship Number", JOptionPane.QUESTION_MESSAGE);
}
}
I am running this code on BlueJ and am using Windows 10 Pro.
Thank you in advance and apologies if this is a beginner question. I am still fairly new to programming.
EDIT: Updated code to give complete source of problem, but it disappeared. I will keep an eye on it to see where the source of the error first occurred.

After completing my project, I finally found why visual artifacts would pop up in all buttons/radio buttons/etc. in my game.
In the GridWorld source code, under the "GridPanel.java" script, the original programmers created a method called "setToolTipsEnabled(boolean flag)". Its function is to pop up a message box next to the cursor when it is hovering over the grid when the game stops running.
When extending GridWorld to create my project, the method reaches past the grid structure and attempts to create a tool tip underneath anything the cursor hovers over. Thus, creating visual artifacts on buttons/radio buttons/etc.
To fix this, I made sure this method was always set to false as I did not need tool tips for my game anyway. This method was implemented in the "GridPanel.java" and "GUIController.java" scripts (in the GridWorld code). I changed following methods to fix this problem:
GridPanel.java
/**
* Construct a new GridPanel object with no grid. The view will be
* empty.
*/
public GridPanel(DisplayMap map, ResourceBundle res)
{
displayMap = map;
resources = res;
// Phillip Sturtevant: Commented out to prevent visual artifacts
//setToolTipsEnabled(true);
}
GUIController.java
/**
* Stops any existing timer currently carrying out steps.
* Phillip Sturtevant Note: keep tool tips hidden to prevent visual artifacts
*/
public void stop()
{
display.setToolTipsEnabled(false); // hide tool tips while stopped
timer.stop();
running = false;
}
Alternatively, the method calls could be omitted entirely, but I commented them out in case I needed them in the future.
For reference, the method below sets the tool tips visibility in GridWorld (located in "GridPanel.java"):
/**
* Enables/disables showing of tooltip giving information about the
* occupant beneath the mouse.
* #param flag true/false to enable/disable tool tips
*/
public void setToolTipsEnabled(boolean flag)
{
if ("hide".equals(System.getProperty("gridworld.gui.tooltips")))
flag = false;
if (flag)
ToolTipManager.sharedInstance().registerComponent(this);
else
ToolTipManager.sharedInstance().unregisterComponent(this);
toolTipsEnabled = flag;
}

How to simulate a real mouse click using java?

I'm attempting to perform a mouse click in Java, to click something in an external program. To do this, I'm using java.awt.robot, and the following code:
Robot bot = new Robot();
int mask = InputEvent.MOUSE_BUTTON1_DOWN;
bot.mouseMove(x, y);
bot.mousePress(mask);
bot.mouseRelease(mask);
Here's the problem. The external program is able to detect that this click is computer-generated and not human-generated, and hence, its rejecting this click.
I have already tried moving the mouse there naturally and that didn't have any effect. So my guess is, that it must be listening to the keyboard state or such, and telling from that, that the click is computer generated.
What do I have to do to set all keyboard / mouse states to act in the same way as a normal mouse click would?

Well I had the same exact requirement, and Robot class is perfectly fine for me. It works on windows 7 and XP (tried java 6 & 7).
public static void click(int x, int y) throws AWTException{
Robot bot = new Robot();
bot.mouseMove(x, y);
bot.mousePress(InputEvent.BUTTON1_DOWN_MASK);
bot.mouseRelease(InputEvent.BUTTON1_DOWN_MASK);
}
May be you could share the name of the program that is rejecting your click?

FYI, in newer versions of Windows, there's a new setting where if a program is running in Adminstrator mode, then another program not in administrator mode, cannot send any clicks or other input events to it. Check your source program to which you are trying to send the click (right click -> properties), and see if the 'run as administrator' checkbox is selected.

it works in Linux. perhaps there are system settings which can be changed in Windows to allow it.
jcomeau#aspire:/tmp$ cat test.java; javac test.java; java test
import java.awt.event.*;
import java.awt.Robot;
public class test {
public static void main(String args[]) {
Robot bot = null;
try {
bot = new Robot();
} catch (Exception failed) {
System.err.println("Failed instantiating Robot: " + failed);
}
int mask = InputEvent.BUTTON1_DOWN_MASK;
bot.mouseMove(100, 100);
bot.mousePress(mask);
bot.mouseRelease(mask);
}
}
I'm assuming InputEvent.MOUSE_BUTTON1_DOWN in your version of Java is the same thing as InputEvent.BUTTON1_DOWN_MASK in mine; I'm using 1.6.
otherwise, that could be your problem.
I can tell it worked because my Chrome browser was open to http://docs.oracle.com/javase/7/docs/api/java/awt/Robot.html when I ran the program, and it changed to Debian.org because that was the link in the bookmarks bar at (100, 100).
[added later after cogitating on it today]
it might be necessary to trick the listening program by simulating a smoother mouse movement. see the answer here: How to move a mouse smoothly throughout the screen by using java?

With all respect the most likely thing is that you are mistaken about why the click is being 'rejected'. Why do you think some program is trying to determine if it's human or not? The Robot class (have used it a lot) should send messages that the operating system has no way to distinguish from a user doing the click.

Some applications may detect click source at low OS level. If you really need that kind of hack, you may just run target app in virtual machine's window, and run cliker in host OS, it can help.

You could create a simple AutoIt Script that does the job for you, compile it as an executable and perform a system call there.
in au3 Script:
; how to use: MouseClick ( "button" [, x, y [, clicks = 1 [, speed = 10]]] )
MouseClick ( "left" , $CmdLine[1], $CmdLine[1] )
Now find aut2exe in your au3 Folder or find 'Compile Script to .exe' in your Start Menu and create an executable.
in your Java class call:
Runtime.getRuntime().exec(
new String[]{
"yourscript.exe",
String.valueOf(mypoint.x),
String.valueOf(mypoint.y)}
);
AutoIt will behave as if it was a human and won't be detected as a machine.
Find AutoIt here: https://www.autoitscript.com/

java: how to launch two applications from one launcher

I have 2 classes, and each one of them has a launcher for a form that utilizes them:
DateTester uses DateTest class and is launched by dateLauncher
CylinderTest uses Cylinder class and is launched by cylLauncher
each launcher is simply comprised of
Cylinder program = new Cylinder();
respectively. They both launched fine by themselves. What I would like to do is create a launcher window (just a pane with two buttons) that will launch either program when their buttons is clicked. I just moved everything into the same package (although im thinking that I shouldnt have done that now), and now neither will launch from their respective launcher. I was trying to launch them with something like:
public void actionPerformed(ActionEvent ev)
{
if(ev.getSource() == btnCylinder)
{
Cylinder prgCylinder = new Cylinder();
}
else if (ev.getSource() == btnDate)
{
DateTester prgDate = new DateTester();
}
else{}
}
but it doesnt do anything. I also tried threading them, and that didnt work either. Any suggestions? Or is this actually a lot more complicated than it seems?

turns out it was just the action listener not added for the buttons. paulo answered this in a comment, but i need to close this as answered. thanks paulo.

java mouse capture

How do I capture the mouse in a Java application so that all mouse events (even ones that happen if the mouse is moved outside the app window) are seen by the Java app? This is like the Windows SetCapture function.

You don't; the JVM, or more specifically AWT, only generates input events when Windows sends it input events, and the JVM only registers for those events which occur within it's window.
You might be able to pull it off using JNI, but then again you might not - it will depend if you can get your hands on the information required by the underlying API. Since that's likely to be a window handle, you won't have what you need to invoke the API, even from JNI.

You have to hook the mouse at the operating system level. Windows(Swing, AWT, MFC, etc....) are only aware of mouse movements within their bounds. If you need a way to access the current position of the mouse regardless of where the mouse is on the screen, you need to write an Input Hook: Input Hooks. You can then use JNI or read the STDOUT from a win32 console application designed to use the Input Hook to forward mouse events/positions to your Java code. I use the latter method in some of my user interface test cases with success.

I needed to do that too!
I after searching the web I found that its possible to use the moveMouse in java.awt.Robot.
Basically use Robot to move the mouse into center of your frame. If user moves it: check how much and move it back to center.
No additional packets or JNI are needed for this (my demo uses JOGL and vecmath but that's for the graphics). Is it good enough? Try the demo, its here:
http://www.eit.se/hb/misc/java/examples/FirstPersonJavaProtoGame/
If the above solution is not good enough then perhaps lwjgl is what you need:
http://www.lwjgl.org/javadoc/org/lwjgl/input/Mouse.html
/Henrik Björkman

Just use the system-hook library available on gitHub https://github.com/kristian/system-hook
This only apply to windows-based systems but really simple to implement.
Sample usage
import lc.kra.system.keyboard.GlobalKeyboardHook;
import lc.kra.system.keyboard.event.GlobalKeyAdapter;
import lc.kra.system.keyboard.event.GlobalKeyEvent;
public class GlobalKeyboardExample {
private static boolean run = true;
public static void main(String[] args) {
// might throw a UnsatisfiedLinkError if the native library fails to load or a RuntimeException if hooking fails
GlobalKeyboardHook keyboardHook = new GlobalKeyboardHook();
System.out.println("Global keyboard hook successfully started, press [escape] key to shutdown.");
keyboardHook.addKeyListener(new GlobalKeyAdapter() {
#Override public void keyPressed(GlobalKeyEvent event) {
System.out.println(event);
if(event.getVirtualKeyCode()==GlobalKeyEvent.VK_ESCAPE)
run = false;
}
#Override public void keyReleased(GlobalKeyEvent event) {
System.out.println(event); }
});
try {
while(run) Thread.sleep(128);
} catch(InterruptedException e) { /* nothing to do here */ }
finally { keyboardHook.shutdownHook(); }
}
}