In my LibGDX game, I have a raster of clickable Actors. I want the player to be able to swipe across them and get the Actor where the swipe stops.
I don't want a GestureListener, the only thing I need is a touchUp event on the touchDown generated on another Actor. For example: think about Androids login screen where you swipe a pattern to unlock, but I only need an event for the last dot/Actor.
I have tried using touchDown / touchUp, but the event always fires on the Actor where the touchDown occurred.
A fine solution would be to get events for every Actor hit by the swipe, and then get a global touchUp event. Is this possible in a relatively accessible way - eg. without writing a whole new InputListener?
In touchUp() of your listener, call hit on the parent WidgetGroup of all your clickable Actors to see which one the finger is over when it is released. Note that since you're adding the actors to the group, the group needs to be added to the stage instead of adding the widgets to the stage directly. And remember that an Actor's X and Y are relative to its parent.
final WidgetGroup parent = new WidgetGroup();
InputListener inputListener = new InputListener(){
private final Vector2 tmp = new Vector2();
public boolean touchDown (InputEvent event, float x, float y, int pointer, int button) {
return true;
}
public void touchUp (InputEvent event, float x, float y, int pointer, int button) {
event.getTargetActor().localToParentCoordinates(tmp.set(x, y));
Actor releaseOverActor = parent.hit(tmp.x, tmp.y, true);
if (releaseOverActor != null){
//doSomethingTo(releaseOverActor);
}
}
}
for (Actor clickable : clickableActors){
parent.add(clickable);
clickable.addListener(inputListener);
}
The above is a little bit simplified. You might want to return true one touchDown only if pointer 0 is used, for example.
Related
while working on the listener class and implementing handling of multiple touch gesture I came across a possible bug.
The code implementation
public class MyListener extends ClickListener {
private List<Pointer> pointers = new ArrayList<Pointer>();
#Override
public boolean touchDown(InputEvent event, float x, float y, int pointerIndex, int button) {
System.out.println("Listener: touch down" + pointerIndex);
pointers.add(new ListenerPointer(x, y, button));
event.handle();
return super.touchDown(event, x, y, pointerIndex, button);
}
#Override
public void touchDragged(InputEvent event, float x, float y, int pointerIndex) {
System.out.println("Listener: dragged " + pointerIndex);
// Update the current point the user is dragging.
for (ListenerPointer pointer : pointers) {
if (pointer.getPointerIndex() == pointerIndex) {
pointer.update(x, y);
event.handle();
}
}
}
}
While touching down on the screen with a new finger, and still holding the old finger on the screen the indexPointer increases. Resulting in the following log:
Listener: touch down0
Listener: touch down1
If I then move both fingers across the screen, it will only fire the touchDragged event with the pointerIndex always zero. Even though the touchDown gesture said it has a pointerIndex of 1. The log of the touchDragged is always:
Listener: dragged 0
Listener: dragged 0
I think it might be a bug in the code of LibGDX, since such a simple piece of code could not really go wrong.
I thought that I had carefully read the documentation of touchDragged, but what a fool I am. It states the following:
Called when a mouse button or a finger touch is moved anywhere, but only if touchDown previously returned true for the mouse button or touch.
I guess that super.touchDown(event, x, y, pointerIndex, button) only return true if the pointerIndex is 0. Explaining the reason why the touchDragged events did not fire for pointerIndex > 0.
The simple fix is to make touchDown always return true
I use the following code to match the user touch to a ball object's position, so when the user touches the ball it bounce back up. Code:
int x1 = Gdx.input.getX();
int y1 = Gdx.input.getY();
Vector3 input = new Vector3(x1, y1, 0);
cam.unproject(input);
if(ball.getBoundingCircle().contains(input.x, input.y)) {
ballBounce();
}
But I have a problem with the touch. If the user touches a certain position on screen for a moment and a ball (after a while more appear) about to reach the position the user touched, the ball will recognize itself as been touched and the ballBounce(); method will start and continue with other balls that reach to the same position until the user touch another position on the screen but then that position will be fixed till the new one... Do someone know how I can bypass that problem so if the user stop touching the screen then where he\she touched won't affect the ball objects?
It seems that you are not using any input processor.
Make your class implement InputProcessor and make your touchDown method look like this.
#Override
touchDown(InputEvent event, float x, float y, int pointer, int button) {
Vector3 input = new Vector3(x, y, 0);
cam.unproject(input);
if (ball.getBoundingCircle().contains(input.x, input.y)) {
ballBounce();
}
}
ClickListener (LibGDX API)
I have a LibGDX scene with a couple of Images (the Actor subclass). I want to drag one Image and drop it on another. I started with the source code located at DragDropTest.java. Since I basically want the source to be the payload I've tried modifying payload.setDragActor to use the source Image. It kind of works, I need to add the code to place the payload actor back in the stage but that isn't my issue.
My problem that that the payload (when it's the source actor or a separate actor) doesn't really get dragged. Instead what happens is the payload actor positions itself slightly down and to the right of the mouse cursor. I want to place the payload, not point to where I want the payload placed. It doesn't feel like dragging at all, it feels like something is following the cursor. I see the same behavior on the Android emulator as I do on the desktop version of the app.
I went digging through the LibGDX source for com.badlogic.gdx.scenes.scene2d.utils.DragAndDrop and found the answer. The code places the payload +14 in the X direction from the cursor and (-20 - payLoadActor.getHeight()) in the Y direction which is why I'm not able to visually drag the payload. There is a setDragActorPosition method that can be used to correct the position. If you always want the dragged payload to be centered under the cursor you can do:
final DragAndDrop dragAndDrop = new DragAndDrop();
dragAndDrop.setDragActorPosition(-(sourceImage.getWidth()/2), sourceImage.getHeight()/2);
If you want the dragged payload to maintain its placement under the cursor/finger than you have to use the cursor position when calling setDragActorPosition in the dragStart method.
final DragAndDrop dragAndDrop = new DragAndDrop();
dragAndDrop.addSource(new DragAndDrop.Source(sourceImage) {
public DragAndDrop.Payload dragStart (InputEvent event, float x, float y, int pointer) {
DragAndDrop.Payload payload = new DragAndDrop.Payload();
payload.setDragActor(sourceImage);
dragAndDrop.setDragActorPosition(-x, -y + sourceImage.getHeight());
return payload;
}
public void dragStop (InputEvent event, float x, float y, int pointer, Target target) {
sourceImage.setBounds(50, 125, sourceImage.getWidth(), sourceImage.getHeight());
if(target != null) {
sourceImage.setPosition(target.getActor().getX(), target.getActor().getY());
}
virtualStage.addActor(sourceImage);
}
});
You're not showing any code, so it's hard to know what you are actually doing. Based on your description, it sounds like you are placing the payload at where the cursor is rather than moving it the same offset as the cursor moved since you started dragging.
Assuming you're using an ActorGestureListener, this is what I do in my app.
float touchX, touchY;
public void touchDown(InputEvent ev, float x, float y, int pointer, int button) {
touchX = x;
touchY = y;
...
}
public void pan(InputEvent ev, float x, float y, float dx, float dy) {
moveBy(x - touchX, y - touchY);
...
}
This way you are moving your actor by the same amount as the mouse cursor moved, so it's like the pointer "glued" itself to whereever you touched your actor. Also, I believe the events in libgdx makes it so that you will not receive the pan events until the cursor has moved a bit inside your actor, so be aware of that when testing (moving the cursor a few pixels only will not trigger the pan events).
I want to make a game where you can build stuff by dragging and dropping objects into place. I think LibGDX only supports DragNDrop on Actors, but I need physics on bricks in order to make them fall down if the construction is not stable.
So far, my approach to drag and drop is:
for(Brick b : map.getList()){
final Image im = new Image(b.ar);
stage.addActor(im);
im.setPosition(b.posX, b.posY);
im.setOrigin(b.posX, b.posY);
im.addListener((new DragListener() {
public void touchDragged (InputEvent event, float x, float y, int pointer) {
im.setOrigin(x, y);
im.setPosition(x, y);
//System.out.println("touchdragged ---> X=" + x + " , Y=" + y);
}
}));
}
where the map.getLists contains all bricks to be painted. b.ar is the texture to be painted.
With this aproach [this] is what happens. I don't know what may be causing it.
#Override
public void render(float delta) {
spritebatch.begin();
map.getWorld().step(1/60f, 6, 2);
renderer.render(map.getWorld(), camera.combined);
if(Gdx.input.justTouched()){
Vector3 touchPoint = new Vector3(Gdx.input.getX(), Gdx.input.getY(),0);
camera.unproject(touchPoint.set(Gdx.input.getX(), Gdx.input.getY(), 0));
System.out.println(touchPoint);
}
stage.draw();
spritebatch.end();
}
Of course i'd like to make the body fell (with the box 2d engine from libgdx) if you drop the object and it has nothing under it.
Thanks in advance
You're setting the origin in your listener callback to a screen coordinate. That is not going to work.
The origin is used to define the "center" of your object, so when you reposition it, Libgdx knows which part of the actor to put where. Generally the origin is either the bottom left corner of the object (I think this is the default) or its the center of the object.
I guess you may want to reset the origin so if someone taps on the left edge of a brick and then you reposition the object you'll reposition that point on the brick (and not reposition the bottom left corner of the brick). To do that you'll need to convert the screen coordinates into coordinates in the actor's space.
That's all somewhat icky though. I think you'd be better off just doing relative repositioning. Instead of trying to position the brick absolutely with setPosition just reposition it relatively:
im.setPosition(im.getX() + dx, im.getY() + dy);
Then it doesn't matter where the "origin" is.
You'll have to compute dx and dy in your listener based on the previous touch point.
It appears that the drag listener gives coordinates relative to the origin of the actor that is raising the event. That is a bit strange when you are moving that actor in response to the drag events, because the origin keeps changing. Essentially, I found that if I just move the actor by the x and y values of the event, it will follow the mouse or finger.
One improvement is to record the position that the drag started at and use it as an offset, so the pointer stays the same distance from the actor's origin.
Another option might be to add the listener to the stage instead of the button. I expect the coordinates would then be relative to the stage's origin, which is not changing. I haven't tried that technique.
Here's the code I used to drag a button horizontally:
DragListener dragListener = new DragListener() {
private float startDragX;
#Override
public void dragStart(
InputEvent event,
float x,
float y,
int pointer) {
startDragX = x;
}
#Override
public void drag(InputEvent event, float x, float y, int pointer) {
insertButton.translate(x - startDragX, 0);
}
};
dragListener.setTapSquareSize(2);
insertButton.addListener(dragListener);
If you want to drag something in two dimensions, just copy the x code for the y position.
I asked this at the libgdx forums but didn't get a response so I was hoping y'all could help me out:
I have Actors that represent game pieces. What I'm trying to do is make it so the player can click-and-drag the tile to move it around the screen and rotate it multiple times before submitting the placeTile command. From what I understand of DragAndDrop it doesn't seem to be designed with my use case in mind so I figured I'd instead attach a dragListener listener to each game piece (code below). It works well for dragging, except I can't figure out how to set the 'minimum distance before drag starts' to 0... but that's not my main question (though any insights would be appreciated )
Anyway, the big problem comes in when I rotate the actor, and then try to drag it: At 30 degrees rotation, drag acts almost like normal: at 60 degrees, very small movements of the mouse send the actor moving in a tight circle very quickly. Another 30 degrees, the tile actor exits the screen in 1-2 frames, moving in a wide arc. If the actor is rotated clockwise, it's movements are clockwise; same pattern for counter-clockwise.
It looks like the translation of the actor is taking rotation into account; I guess my question is, is it possible to rotate an Actor/Group without the rotation affecting future translations? Alternatively, is there a better way to drag an Actor around the screen based on touch/mouse input? I included some code below: I imagine I'm screwing up something basic, but I can't figure out what:
// during initial stage creation
tileActor.setOrigin(tileActor.getWidth() / 2, tileActor.getHeight() / 2);
tileActor.addListener(new DragListener() {
public void dragStart(InputEvent event, float x, float y,
int pointer) {
chosenTileActor = event.getTarget();
}
public void drag(InputEvent event, float x, float y, int pointer) {
Actor target = event.getTarget();
target.translate(x, y);
}
});
And for the listener that deals with rotation via scrolling mouse wheel:
multiplexer.addProcessor(new InputAdapter() {
#Override
public boolean scrolled(int amt) {
if (chosenTileActor == null)
return false;
else
chosenTileActor.rotate(amt * 30);
return true;
}
});
Any pointers? Am I even going the right direction by using DragListener?
Thanks for reading!
Instead of translating, just set the actor's position directly to the stage coordinates of your drag event:
tileActor.addListener(new DragListener() {
private float offsetX, offsetY;
#Override
public void dragStart(InputEvent event, float x, float y, int pointer) {
Actor target = event.getTarget();
this.offsetX = event.getStageX() - target.getX();
this.offsetY = event.getStageY() - target.getY();
}
#Override
public void drag(InputEvent event, float x, float y, int pointer) {
event.getTarget().setPosition(event.getStageX() - offsetX, event.getStageY() - offsetY);
}
});
I'm computing the offsets in dragStart so that the actor doesn't immediately jump to wherever I clicked when I started dragging (making the drags relative to my mouse). Tested this and it works with any rotation.