即使已加载我的文件（Android Studio，libGDX，Java），AssetManager.get（）也返回null

Question

I'm using libGDX's AssetManager, I have checked that my files have been loaded using the .update() method. Note that my boolean loaded is true once AssetManager.update() returns true (which means everything has been loaded).

if(loaded)
{
    if(player == null && walls == null)
    {
        player = new Player(this);
        walls = new WallList(this);
    }
    //unrelated stuff
}

My player object uses a texture and it works just fine. But my walls object also uses a texture but it crashes. Here's my setup (in my WallList constructor)

//unrelated stuff
this.colors = new HashMap<Color, String>();
this.spawningColor = Color.red;

colors.put(Color.red, "sqr_wall_red");

for(int i = 0; i < wallCountNeeded; i++)
{
    this.add(new Wall(getTextureFromColor(spawningColor), i*wallWidth, 0));
}

In the code above, I make a HashMap and assign "sqr_wall_red" which is also the name of the png. I then call TextureFromColor to get the Texture from the AssetManager while using Color.Red as parameter.

private Texture getTextureFromColor(Color color)
{
    return game.getAssetManager().get("data/Sprites/" + colors.get(color) + ".png", Texture.class);
}

And I get this error

Exception in thread "LWJGL Application" java.lang.NullPointerException at com.cedric.game.geometry.WallList.getTextureFromColor(WallList.java:45) at com.cedric.game.geometry.WallList.(WallList.java:39)

I'm pretty confident in the fact that the path is alright since I load it like this

assetManager.load("data/Sprites/sqr_wall_red.png", Texture.class);

and if I print the path I'm using for assetManager.get()

System.out.println("data/Sprites/" + colors.get(spawningColor) + ".png");

I get this as an output (which matches the exact input in the assetManager.load()

data/Sprites/sqr_wall_red.png

I think I have provided sufficient information in order to resolve my issue, but if you need more I will gladly show more.

Answer 1

return game.getAssetManager().get("data/Sprites/" + colors.get(color) + ".png", Texture.class);

There are 3 possible places in that line of code that can cause an NPE: game , getAssetManager() , and colors . You need to determine which one it is.