Asset Management in LibGDX

package net.dermetfan.util.libgdx;

import com.badlogic.gdx.Gdx;
import com.badlogic.gdx.assets.AssetDescriptor;
import com.badlogic.gdx.assets.AssetManager;
import com.badlogic.gdx.files.FileHandle;
import com.badlogic.gdx.graphics.g2d.Animation;
import com.badlogic.gdx.graphics.g2d.TextureAtlas;

/** This class is supposed to be edited by the user.<br/>
 *  Pay attention to the comments.
 *
 *  <p>
 *  To add an asset:
 *      <ul>
 *          <li>If it should be {@link #queue() queued}, add it to {@link Descriptors}, else to {@link OnDemandFileHandles} for manual use</li>
 *          <li>Add a field for direct access</li>
 *          <li>Initialize your asset field in {@link #init()}</li>
 *          <li>If necessary, dispose your asset field in {@link #dispose()}</li>
 *      </ul>
 *  </p>
 *
 *  <p>
 *      To load the {@link #queue() queued} assets:<br/>
 *      <code>Assets.queue();<br/>
 *      while(!Assets.update()) // or just Assets.manager.finishLoading() followed by Assets.init()<br/>
 *          ;<br/>
 *      // all assets are loaded and Assets#init() was called</code>
 *  </p>
 *
 *  <p>
 *      To access your assets:<br/>
 *      <code>Assets.yourCustomAssetField</code>
 *  </p>
 *
 *  <p>
 *      To access on-demand assets (example):<br/>
 *      <code>new Texture(Assets.OnDemandFileHandles.blackImg.fileHandle.path())</code>
 *  </p>
 *
 *  @author dermetfan */
public abstract class Assets {

    /** responsible for loading the assets */
    public static final AssetManager manager = new AssetManager();

    /** {@link AssetManager#load(AssetDescriptor) queues} all not loaded {@link Descriptors assets} for loading */
    public static void queue() {
        for(Descriptors desc : Descriptors.values())
            if(!manager.isLoaded(desc.descriptor.fileName))
                manager.load(desc.descriptor.fileName, desc.descriptor.type);
    }

    /** {@link #init() Initializes} when loading is finished. Assets must have been {@link #queue() queued} before.
     *  @see AssetManager#update() */
    public static boolean update() {
        if(manager.update()) {
            init();
            return true;
        }
        return false;
    }

    /* DON'T TOUCH ANYTHING ABOVE THIS LINE
     * ADD Descriptors AND OnDemandFileHandles BELOW */

    /** {@link AssetDescriptor AssetDescriptors} of assets that should be {@link Assets#queue() queued} */
    public static enum Descriptors {
        playerAtlas(new AssetDescriptor<TextureAtlas>(Gdx.files.internal("img/player/player.pack"), TextureAtlas.class));

        public final AssetDescriptor<?> descriptor;

        private Descriptors(AssetDescriptor<?> descriptor) {
            this.descriptor = descriptor;
        }

    }

    /** {@link FileHandle FileHandles} of assets that should not be {@link Assets#queue() queued} */
    public static enum OnDemandFileHandles {
        map1(Gdx.files.internal("maps/map.tmx"));

        public final FileHandle fileHandle;

        private OnDemandFileHandles(FileHandle fileHandle) {
            this.fileHandle = fileHandle;
        }

    }

    /* ADD FIELDS FOR DIRECT ACCESS TO YOUR ASSETS AND GENERATED ASSETS */

    public static TextureAtlas playerAtlas;
    public static Animation playerStill, playerLeft, playerRight;

    /* ADD INITIALIZATION OF YOUR FIELDS HERE */
    /** Initializes all fields. {@link #update() Loading} must be finished or some fields will be set to null. */
    public static void init() {
        { // player texture atlas and animations
            playerAtlas = manager.get(Descriptors.playerAtlas.descriptor.fileName);
            playerStill = new Animation(1 / 2f, playerAtlas.findRegions("still"));
            playerLeft = new Animation(1 / 6f, playerAtlas.findRegions("left"));
            playerRight = new Animation(1 / 6f, playerAtlas.findRegions("right"));
            playerStill.setPlayMode(Animation.LOOP);
            playerLeft.setPlayMode(Animation.LOOP);
            playerRight.setPlayMode(Animation.LOOP);
        }
    }

    /* DISPOSE YOUR ASSET FIELDS HERE */
    /** disposes all assets */
    public static void dispose() {
        { // player texture atlas and animations
            playerAtlas.dispose();
        }
    }

}