Develop Reference

JavaFX wait for user input

I am writing a board game where I need to check for enemies on the the player is moving and prompt to make an attack. However because of how the game is made the move method is called on the JavaFX application thread, I want to be able to prompt the user if they want to fight an enemy.
My dialogue box which works fine normal uses wait and notify which dont work on the main thread without crashing the program, does anyone know how to pause the execution of this thread until a user clicks one of the buttons.
I apologise for the description, its late.
Method that checks for enemies
This method checks for the enemies and returns the enemy if the user selected yes. It runs on the JavaFX Thread.
private Ship pathBattle(Vector gridPosition){
//Check if there are ships on the path to the destination
for(Button cell : activeButtons){
//Check the button position is not that of the current button, dont go past the current button
Vector pixPosition = new Vector(cell.getLayoutX(), cell.getLayoutY());
//Convert to a grid referance
Vector gridPos = Vector.pixToGrid(pixPosition);
if(!gridPos.equals(gridPosition)){
//This button is not the destination
//Check for any ships on that cell
Ship collided = Ship.isOccupiedButton(cell);//Returns the ship if there is one on the cell
if(collided != null){
//There is a ship, prompt to battle
boolean battle = UtilPopups.showConfirmationDialog("Do you want to battle " + collided.getName(), "YAR!", "NAY!");
Game.printError("Ship collision");
if(battle){
return collided; //Return the ship to battle
}
}
}
//On to the next button
}
return null;
}
The code to display the Popup
This does work in other areas of the porgram with no issue
public static boolean showConfirmationDialog(String lblPrompt, String btnYes, String btnNo){
//Check if the confirmation controller is not null
if(confirmationDialog != null){
confirmationDialog.lbl_prompt.setText(lblPrompt);
confirmationDialog.btn_no.setText(btnNo);
confirmationDialog.btn_yes.setText(btnYes);
//Show the base
show(confirmationDialog.base_pane);
//Pause this thread until user input is given from GUI thread
synchronized (confirmationDialog) {
try{
confirmationDialog.wait();
} catch (Exception e) {
e.printStackTrace();
}
}
//Program resumed, user input given and stored in response
if(confirmationDialog.response.equals("yes")){
confirmationDialog.response = null; //Set back to null
return true;
} else {
confirmationDialog.response = null; //Set back to null
return false;
}
}
//Class not initialized
Game.printError("UtilPopups->showConfirmationDialog: Dialog NULL!");
return false;
}

For blocking any caller thread during showing dialog, for example:
static private void showAndBlock(Dialog dialog) {
if (Platform.isFxApplicationThread()) {
dialog.showAndWait();
} else {
CountDownLatch lock = new CountDownLatch(1);
Platform.runLater(() -> {
dialog.showAndWait();
lock.countDown();
});
try {
lock.await();
} catch (InterruptedException e) {
// Just in case you call yourTherad.interrupt(),
// the thread will be joined forcibly through here.
}
}
}
But I'm not sure whether or not it works in your threading design.

The collided method literally doesnt nothing, it doesn't ask for a input so it can't work.
I think, sorry not good english

Delete body box2d

Could anyone tell me why this is returning the error
'AL lib: (EE) alc_cleanup: 1 device not closed'
//mouseJoint collision callback
private QueryCallback queryCallback = new QueryCallback() {
#Override
public boolean reportFixture(Fixture fixture) {
if(fixture.getBody() == chest){
//add to remove list
bodiesToRemove.add(chest);
}
if (fixture.testPoint(tmp.x, tmp.y)){
reportFixture = fixture.getBody();
}
if (!fixture.testPoint(tmp.x, tmp.y))
return false;
//assigning bodyB to fixture
jointDef.bodyB = fixture.getBody();
jointDef.target.set(fixture.getBody().getWorldCenter());
//jointDef.target.set(tmp.x, tmp.y);// initial target point coincide with body anchor
joint = (MouseJoint) world.createJoint(jointDef);// creating the join the physics world
return false;
}
};
//main rendering loop
public void render(float delta) {
// TODO Auto-generated method stub
//code clears the screen with the given RGB colour (black)
Gdx.gl.glClearColor( 0f, 0f, 0f, 1f );
Gdx.gl.glClear( GL20.GL_COLOR_BUFFER_BIT );
stage.setCamera(camera);
stage.act(Gdx.graphics.getDeltaTime());
camera.position.x= chest.getPosition().x;
camera.update();
stage.draw();
world.step(1 / 60f, 8, 3);
renderer.render(world, camera.combined);
/////////////////////////////////////////////////////////////////
// this is the code that is causing the error when I try to delete a body
if(bodiesToRemove != null){
for(int i = 0; i <bodiesToRemove.size; i++){
Body b = bodiesToRemove.get(i);
if(b != null){
world.destroyBody(b);
b.setUserData(null);
b = null;
}
bodiesToRemove.clear();
}
}
////////////////////////////////////////////////////////////
}
////////////////////////////////////////////////////////////////////////////
I've changed this and it work's(pasted below), if anyone would like to explain the right way to do this or if this is the correct way that would be helpful.
I just added a boolean to prevent it from destroying the joint
// ////////////////// TOUCH EVENT ///////////////////////////////
//Called when a finger was lifted or a mouse button was released.
#Override
public boolean touchUp(int screenX, int screenY, int pointer, int button) {
//If no mouseJoint do nothing
System.out.println("touch" + (screenY*0.01f));
System.out.println("touch" + (screenX*0.01f));
if (joint == null)
return false;
//When user is not touching Screen destroy the
//mouseJoint/set to null
if(ran == false){
world.destroyJoint(joint);
joint = null;}
ran = false;
return true;
}
////////////////////////////////
/////////////////////////////////
if(!world.isLocked() && world.getBodyCount() > 0 ){
for(int i = 0; i <bodiesToRemove.size; i++){
Body b = bodiesToRemove.get(i);
if(b == null){
bodiesToRemove.removeIndex(i);
continue;
}
world.destroyBody(b);
ran = true;
bodiesToRemove.removeIndex(i);
}
}else{
bodiesToRemove.clear();
}
////////////////////////////////////////////////////////////

Box2D throws some odd errors, this is not one of them.
I assume you are using LibGDX, basically what is happening is a crash due to Box2D (I also assume it pops up saying "java or whatever has stopped responding"), this error you are seeing is thrown when the app exits while OpenAL is closing streams and cleaning up resources. Don't worry about that too much.
Ensure you are checking of the world is locked before destroying bodies, it usually throws an error and prints a clear message telling you this, depending on the way you are removing bodies.
if(!world.isLocked())
// do clean up code here
You don't need to clean up the variable inside local scope, or clear the userdata inside the body as the body as it will no longer exist in reference (unless you have it stored somewhere else).
So the proper code would be something like this:
if(!world.isLocked()){
for(int i = bodiesToRemove.size - 1; i--){
Body b = bodiesToRemove.get(i);
if(b == null){
bodiesToRemove.removeAt(i);
continue;
}
world.destroyBody(b);
bodiesToRemove.removeAt(i);
}
}
You are also clearing a list during iteration, not a good idea.
EDIT
The only other thing I can think of that is causing this problem is trying to delete a body that is not actually in the worlds body list.
Try the following:
// Ensure world is not locked AND that there is even bodies in the world
if(!world.isLocked() && world.getBodyCount() > 0){
for(int i = bodiesToRemove.size - 1; i--){
Body b = bodiesToRemove.get(i);
if(b == null){
bodiesToRemove.removeAt(i);
continue;
}
world.destroyBody(b);
bodiesToRemove.removeAt(i);
}
}else{
// There is no bodies in the world, so the bodies in our list are just
// random memory hogs, leave them for the GC by clearing the list
bodiesToRemove.clear();
}
EDIT
As stated by the OP, the problem lies with this block of code:
private QueryCallback queryCallback = new QueryCallback() {
#Override
public boolean reportFixture(Fixture fixture) {
if(fixture.getBody() == chest){
//add to remove list
bodiesToRemove.add(chest);
}
if (fixture.testPoint(tmp.x, tmp.y)){
reportFixture = fixture.getBody();
}
if (!fixture.testPoint(tmp.x, tmp.y))
return false;
//assigning bodyB to fixture
jointDef.bodyB = fixture.getBody();
jointDef.target.set(fixture.getBody().getWorldCenter());
//jointDef.target.set(tmp.x, tmp.y);
joint = (MouseJoint) world.createJoint(jointDef);
return false;
}
};
More specifically, this line:
joint = (MouseJoint) world.createJoint(jointDef);
The query callback is triggered during a world step. In Box2D, you can not create or destroy bodies, fixtures, and joints during the world step.
You have to create it outside this method, the simplest way to do it is via a flag. Set a flag to true and store the instance of the fixture somewhere and handle it outside in the game loop using said flag and fixture.

libgdx-Actions create stuttering

I try to improve the movement of my figures but i dont find the real reason why they stutter a bit. I am moving them with an SequenceAction containing an MoveToAction and an RunnableAction that does reset the moveDone flag so there can be started a new move.
The game itself is gridbased so if a move is done the squence starts a move to the next grid depending on the direction. So here is how it looks like:
note that this is inside of the Act of the figure
....//some more here
if (checkNextMove(Status.LEFT)) //check if the position is valid
{
status = Status.LEFT; //change enum status
move(Status.LEFT); // calls the move
screen.map.mapArray[(int) mapPos.x][(int) mapPos.y] = Config.EMPTYPOSITION;
screen.map.mapArray[(int) (mapPos.x - 1)][(int) mapPos.y] = Config.CHARSTATE;
mapPos.x--;
moveDone = false;
}
//... same for the up down right and so on.
//at the end of this checking the updating of the actor:
// methode from the absctract to change sprites
updateSprite(delta);
super.act(delta); // so the actions work
//end of act
And here is the move Method that does add the Actions
protected void move(Status direction)
{
// delete all old actions if there are some left.
clearActions();
moveAction.setDuration(speed);
//restart all actions to they can used again
sequence.restart();
switch (direction)
{
case LEFT:
moveAction.setPosition(getX() - Config.TILE_SIZE, getY());
addAction(sequence);
break;
case RIGHT:
moveAction.setPosition(getX() + Config.TILE_SIZE, getY());
addAction(sequence);
break;
case UP:
moveAction.setPosition(getX(), getY() + Config.TILE_SIZE);
addAction(sequence);
break;
case DOWN:
moveAction.setPosition(getX(), getY() - Config.TILE_SIZE);
addAction(sequence);
break;
default:
break;
}
}
The figures dont really move smothy.
Anyone does see a misstake or isnt it possible to let them move smothy like this?
It always stutter a bit if a new move is started. So i think this might not work good. Is there a differnt approach to move them exactly from one Grid to an nother? (Tried it myself with movementspeed * delta time but this does not work exactly and i struggeled around and used the Actionmodel)
it seems to make troubles with the one Frame where it does not move for example.
Here is an mp4 Video of the stuttering:
stuttering.mp4
just to mention, the camera movement is just fine. it's smothy but the figure stutters as you can see i hope

If you use your moveAction each move, you should call moveAction.restart() to reset the counter inside it:
// delete all old actions if there are some left.
clearActions();
sequence.reset(); // clear sequence
// add movementspeed. Note it can change!
moveAction.restart();
moveAction.setDuration(speed);
UPDATE:
Now issue occurs, because you call restart of SequenceAction after clearActions(). If your clearActions() removes all actions from SequenceAction then restart will be called for empty SequenceAction. So, do this instead:
//restart all actions to they can used again
sequence.restart();
// delete all old actions if there are some left.
clearActions();
moveAction.setDuration(speed);

Okay so i solved it myself. It has nothing todo with changing sequences around. It has something todo with the updatefrequency of the act() of the figures. The MoveToAction interpolates between the 2 points given by time. So if the last update, updates the MoveToAction by "to much time" it would need to go over the 100% of the action. So it would move to far but the action does not do this it set the final position and thats what it should do. Thats why it does not look fluent.
So how to solve this issue?
By decreasing the updatetime the "to far movement" decreases too because the steplength is getting smaller. So i need to increase the updatespeed above the 60fps. Luckily i got an thread for my updating of the figures and positions and so on. GameLogicThread. This ran on 60fps too. So i solved the stuttering by increasing it's frequence. up to around 210fps at the moment so the "overstep" is minimal. You can't even notice it.
To Show how my thread works:
public class GameLogicThread extends Thread
{
private GameScreen m_screen;
private boolean m_runing;
private long m_timeBegin;
private long m_timeDiff;
private long m_sleepTime;
private final static float FRAMERATE = 210f;
public GameLogicThread(GameScreen screen)
{
m_screen = screen;
setName("GameLogic");
}
#Override
public void run()
{
m_runing = true;
Logger.log("Started");
while (m_runing)
{
m_timeBegin = TimeUtils.millis();
// hanlde events
m_screen.m_main.handler.processEvents();
synchronized (m_screen.figureStage)
{
// now figures
if (m_screen.m_status == GameStatus.GAME)
{
m_screen.character.myAct(1f / GameLogicThread.FRAMERATE);// and here it is ;)
m_screen.figureStage.act(1f / GameLogicThread.FRAMERATE);
}
}
m_timeDiff = TimeUtils.millis() - m_timeBegin;
m_sleepTime = (long) (1f / GameLogicThread.FRAMERATE * 1000f - m_timeDiff);
if (m_sleepTime > 0)
{
try
{
Thread.sleep(m_sleepTime);
}
catch (InterruptedException e)
{
Logger.error("Couldn't sleep " + e.getStackTrace());
}
}
else
{
Logger.error("we are to slow! " + m_sleepTime);
}
}
}
public void stopThread()
{
m_runing = false;
boolean retry = true;
while (retry)
{
try
{
this.join();
retry = false;
}
catch (Exception e)
{
Logger.error(e.getMessage());
}
}
}
}

Android if rectangle contains touch coords then add to array giving weird output

I am building a game that you drag your finger in a sequence from one block to the next.
What I need to happen: when they hover over a block, it adds that block number to an array so I know in which sequence the blocks were touched in. it needs to be dragged from block to block, not clicked (sort of like the android lockscreen app).
What I am doing so far: creating a rectangle for each block using its coordinates and dimensions, then I am checking that if the user's touch is within that rectangle, add that block number to the array.
It seems to be working, but it only works for buttons 1, 2 and 3 (Only 1, 2 and 3 will be added to the array) But if I log the touch to logcat and the buttons dimensions / coordinates, it is picking the thing up, so I don't know why it is not holding the information?
Here is the code:
#Override
public boolean onTouch(View arg0, MotionEvent arg1) {
// TODO Auto-generated method stub
try {
Thread.sleep(50);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
x = (int) arg1.getX();
y = (int) arg1.getY();
if(b1R.contains(x,y)){
arr.add("1");
} else if(b2R.contains(x,y)){
arr.add("2");
} else if(b3R.contains(x,y)){
arr.add("3");
} else if(b4R.contains(x,y)){
arr.add("4");
} else if(b5R.contains(x,y)){
arr.add("5");
} else if(b6R.contains(x,y)){
arr.add("6");
} else if(b7R.contains(x,y)){
arr.add("7");
} else if(b8R.contains(x,y)){
arr.add("8");
} else if(b9R.contains(x,y)){
arr.add("9");
}
if(arr.toString() != null){
Log.d("log", arr.toString());
Log.d("x", ""+x);
Log.d("y", ""+y);
}
return false;
}
#Override
public void onWindowFocusChanged (boolean hasFocus){
super.onWindowFocusChanged(hasFocus);
if(hasFocus){
b1R = new Rect(b1.getLeft(), b1.getTop(), b1.getRight(), b1.getBottom());
b2R = new Rect(b2.getLeft(), b2.getTop(), b2.getRight(), b2.getBottom());
b3R = new Rect(b3.getLeft(), b3.getTop(), b3.getRight(), b3.getBottom());
b4R = new Rect(b4.getLeft(), b4.getTop(), b4.getRight(), b4.getBottom());
b5R = new Rect(b5.getLeft(), b5.getTop(), b5.getRight(), b5.getBottom());
b6R = new Rect(b6.getLeft(), b6.getTop(), b6.getRight(), b6.getBottom());
b7R = new Rect(b7.getLeft(), b7.getTop(), b7.getRight(), b7.getBottom());
b8R = new Rect(b8.getLeft(), b8.getTop(), b8.getRight(), b8.getBottom());
b9R = new Rect(b9.getLeft(), b9.getTop(), b9.getRight(), b9.getBottom());
}
}
this is what is being printed to logcat:
[1,1,1,1,1,1,1,1,1,2,2,1,1,1,1,1,1,1,1,1,1,1,3,3,3,1,1,3,3,3]
and no other buttons?
Please help!
Thanks in advance!

What is B1r? Should you be updating this at some point to account for a new set of locations? You're using Else If statements, which means that as long as
if(b1R.contains(x,y)){
Evaluates to true, none of your other checks will execute.
I would ensure that you don't have b1r's bounds set to the entire screen, or some other incorrect (or possibly "correct" but damaging value).
It's hard to really debug this without more code however.

Trouble with while to make a loop

cameraOn();
while (counter == 1){
if(counter == 0){
cameraOn();
counter += 1;
}else{
cameraOff();
counter -= 1;
}
}
The methods are:
private void cameraOff() {
// TODO Auto-generated method stub
parameters.setFlashMode(Parameters.FLASH_MODE_OFF);
camera.setParameters(parameters);
camera.release();
camera = null;
}
private void cameraOn() {
// TODO Auto-generated method stub
camera = Camera.open();
parameters = camera.getParameters();
parameters.setFlashMode(Parameters.FLASH_MODE_TORCH);
camera.setParameters(parameters);
}
and I have a button who have to break the loop and finish the activity:
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
if (camera == null){
finish();
}else{
parameters.setFlashMode(Parameters.FLASH_MODE_OFF);
camera.setParameters(parameters);
camera.release();
camera = null;
finish();
}
I'm a beginner and I don't understand how does the loop work, I tought with the counter I could do it, but it didn't work.
What I'm trying is to make the camera flash blink every second in a loop until I will press the button. please help me. Thanks

if (counter == 0) will never be true as your loop will exit in that case.

As others have said, entering a loop only when counter == 0 means it will never enter the inner loop requiring counter == 1, and never enter cameraOn().
Try this:
Clear out your onClick method and replace it with:
#Override public void onClick(View v) {
cameraOff();
/* or 'toggle();' if you prefer, see below */
}
(Since it appears to do exactly the same things.)
Comment out / delete that whole nested loop, and be sure to call cameraOn() or toggle() somewhere to get things started.
For setting up the toggle, you can add a static Boolean isFlashActive; (or otherwise detect the flash state, I haven't used that api yet)
..and add a function:
private toggle(){
if ( isFlashActive ) {
cameraOff();
} else {
cameraOn();
}
/* delay? */
}
For the toggle delay, you have a couple options:
First, you can call toggle() from another thread via a Runnable or one of the android options like AsyncTask while adding a wait() into the toggle function to provide the delay;
Second is my personal favorite, which is to setup an intent receiver then use setRepeating() with a PendingIntent.

The following part of your code will never be executed because you only enter the while block if counter == 1.
if(counter == 0){
cameraOn();
counter += 1;
So if you ever entered your while block while (counter == 1), you will always end up calling cameraOff() method. In other words your if statement will never be true and the else statement will be the one to be always executed.