LibGDX - Items and itembox?

ddfh · June 27, 2013, 10:41am

Hi,

In the first picture you can see 5 images (crown, book, key, sword, heart) and a red circle (the red circle shows the touch on the screen).

I show the 5 images with SpriteBatch on the Screen.

Picture 2: Now, when I touch on the crown and swipe the finger on the screen, I want to move the crown. How can I do this? What’s the keyword for that?

And when my finger is in the near of the itembox, it automatically shows a transparent image of the selected Item.

Picture 3: And now, when I move my finger to the right, the book item moved to the left automatically.

Picture 4: Now when I release my finger (look picture 3 for the position), the crown item snaps in the item box. How can I do this? Where can I find snap algorithms. What are they called?

Are there good tutorials or open source code snippets for that?

Thanks!

davedes · June 27, 2013, 1:37pm

This is a typical programming problem where you will need to come up with a solution using some simple logic.

For example:

When the user first clicks the actor, start accepting drag events. Keep hold of the original position on the ground. Move the actor based on the drag.
When the drag is over the inventory slot, toggle the slot to show a transparent version of whatever item is being dragged. When the drag moves out of the inventory slot, hide the transparent icon.
When the drag event ends: if the item is over a slot, place it in that slot. Otherwise leave it to its original place on the ground.

You can accomplish this with drag and drop handling with scene2D:

github.com

libgdx/libgdx/blob/master/tests/gdx-tests/src/com/badlogic/gdx/tests/DragAndDropTest.java

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package com.badlogic.gdx.tests;

import com.badlogic.gdx.Gdx;
import com.badlogic.gdx.graphics.Color;

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Or with DragListener:
http://libgdx.badlogicgames.com/nightlies/docs/api/com/badlogic/gdx/scenes/scene2d/utils/DragListener.html

Or simply with touchDragged of InputProcessor and custom logic for hit-testing and such:
http://libgdx.l33tlabs.org/docs/api/com/badlogic/gdx/InputProcessor.html

ddfh · June 28, 2013, 12:21pm

Thank You! That helped me