Stage.addListener not working in libgdx - input

Question

I am just trying to add a click listener to the stage in libgdx but it is not working here is my code;
stage.addListener(new InputListener() {
#Override
public boolean touchDown(InputEvent event, float x, float y, int pointer, int button) {
Gdx.app.log("CLICK", "LISTENER");
parallaxBackground.reverse();
return super.touchDown(event, x, y, pointer, button);
}
});
This is from my main game screen, which inherits from an abstract screen which calls,
Gdx.input.setInputProcessor(stage);
In the abstract class I also call,
stage.act(delta);
I am most definetely calling super.render() as well from the child class
What is causing this!
EDIT
I don't know if it matters but my stage has no actors but I just want to simply acknowledge a click.

Answer 1

Since you added no actors to your stage, your stage has no substance so it cannot be touched.
You can add create an actor that is the same size as the screen and is aligned with the screen to do what you're trying. Something like this (untested):
Actor screenActor = new Actor(){
public void act (float delta) {
super.act(delta);
Viewport viewport = getStage().getViewport();
width = viewport.getScreenWidth();
height = viewport.getScreenHeight();
x = viewport.getScreenX();
y = viewport.getScreenY();
}
};
stage.addActor(screenActor);
You would add this actor first, so other actors get first crack at intercepting touches, and this is the fallback.

Answer 2

Here is how I solved this problem:
In Photoshop I created a 100x100px image and put only one layer in it and set the opacity of that layer to 1%, I also removed the background (This made a totally transparent image) and saved it as .png to use it as texture.
I created an Actor and called it BgActor and drew the texture to it.
Here is the png image that I created
and here is how my Actor looks like:
The BgActor class:
public class BgActor extends Actor {
private float x, y, width, height;
private Texture texture = new Texture(Gdx.files.internal("images/transparent-bg.png"));
public BgActor(float x, float y, float width, float height) {
this.x = x;
this.y = y;
this.width = width;
this.height = height;
setTouchable(Touchable.enabled);
}
#Override
public void draw(Batch batch, float parentAlpha) {
setBounds(x, y, width, height);
batch.draw(texture, x, y, width, height);
}
public void dispose() {
texture.dispose();
}
}
Implementation (I used your Listener):
BgActor bgActor = new BgActor(0, 0, stage.getWidth(), stage.getHeight);
bgActor.addListener(new InputListener() {
#Override
public boolean touchDown(InputEvent event, float x, float y, int pointer, int button) {
Gdx.app.log("CLICK", "LISTENER");
parallaxBackground.reverse();
return super.touchDown(event, x, y, pointer, button);
}
});
......
stage.addActor(bgActor);
And don't forget to dispose the bgActor in your Screen's hide() method.
Good luck ..