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Making a whole libgdx screne2d group touchable

Posted by Daniel Hölbling on March 18, 2016

When placing a Group with child-controls inside a libgdx stage is is apparently impossible for the whole group to get hit-detection (click-events and touch events), instead only the children in the container will fire touch and click events.

This is something I was struggling with quite some time until I looked at the libgdx source code and found this in Actor.java:

public Actor hit (float x, float y, boolean touchable) {
    if (touchable && this.touchable != Touchable.enabled) return null;
    return x >= 0 && x < width && y >= 0 && y < height ? this : null;

That's how hit-detection is done in libgdx and that's also the reason why no click-events inside the groups bounds where detected. Not so much the code above, because that one works fine. But if you look at the code for scene2d.ui.Group you notice that it is overriding the hit-detection to delegate all calls to it's children, never checking for itself.

So the simple solution here was to just subclass the Group and instead of calling super.hit I brought back the hit-detection from Actor.

Hope this helps.

Filed under libgdx, java, inputs
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