NoSuchMethodError: Minecraft.getMinecraft()

[Jimmeh]

Hi there!

 

I'm jumping into Forge modding for the second time (I didn't last long the first after coming from using Spigot for a few years). All I'm trying to do right now is for the server to send a packet to the player that runs a command. This packet will tell the client to open a GUI. Now, I have the network part of this down, or at least, there's no errors coming from that. The error pops up when I'm trying to call 

Minecraft.getMinecraft().displayGuiScreen(new myGui());

I call this in my implementation of IMessageHandler, making sure that I have registered this handler to be receiving packets on the client side.I have no idea as to why the above code is throwing the NoSuchMethodError when it's running clientside. My only guess is that it has to do with run-time classpaths being different than compile-time, but I have a shadow plugin I'm using with Gradle to shade in my dependencies. Any help is greatly appreciated!

 

Here's where I'm registering my IMessage and IMessageHandler classes:

public class AureliosPacketHandler {

    public static final SimpleNetworkWrapper INSTANCE = NetworkRegistry.INSTANCE.newSimpleChannel("aurelios");
    private static int id = -1;

    public static void init() {
        INSTANCE.registerMessage(PacketOpenGui.GuiPacketHandler.class, PacketOpenGui.class, id++, Side.CLIENT);
    }
}

 

And here's the classes themselves:

public class PacketOpenGui implements IMessage {

    private GuiTypes guiType;

    public PacketOpenGui(){}

    public PacketOpenGui(GuiTypes type){
        this.guiType = type;
    }

    @Override
    public void fromBytes(ByteBuf buf) {
        guiType = GuiTypes.getGuiType(buf.readInt()).get();
    }

    @Override
    public void toBytes(ByteBuf buf) {
        buf.writeInt(guiType.getID());
    }

    public static class GuiPacketHandler implements IMessageHandler<PacketOpenGui, IMessage> {

        @Override
        public IMessage onMessage(PacketOpenGui message, MessageContext ctx) {
            Minecraft.getMinecraft().displayGuiScreen(message.guiType.getGui());
            return null;
        }
    }
}

For reference, GuiTypes is simply an Enum to make things easier on me down the road. Again, thanks for any help!

[jabelar]

Yes, basically your suspicion about run-time class loading is correct. The Minecraft class is not loaded on the server side, but your PackeOpenGUI class is loaded on both sides.

 

What you need to do is use your proxy. You create a method called something like openGui() in your proxy but in the server proxy class you have it do nothing and in the client proxy class you have it call the Minecraft.getMinecraft.displayGuiScreen().

 

Basically you need to collect all your code that is affected by sided loading into the proxy.

[Draco18s]

Or use EntityPlayer.openGui

[Draco18s]

2 minutes ago, diesieben07 said:

Only relevant for GUIs that have a server-side component (Container).

Ok, fair point

[Jimmeh]

13 hours ago, jabelar said:

Yes, basically your suspicion about run-time class loading is correct. The Minecraft class is not loaded on the server side, but your PackeOpenGUI class is loaded on both sides.

 

What you need to do is use your proxy. You create a method called something like openGui() in your proxy but in the server proxy class you have it do nothing and in the client proxy class you have it call the Minecraft.getMinecraft.displayGuiScreen().

 

Basically you need to collect all your code that is affected by sided loading into the proxy.

Okay, this makes sense! However, it's looking like my proxies aren't getting instantiated even though I'm using the annotation. I believe this to be so because I get a NullPointerException when trying to call "proxy.preInit()". I've watched a few tutorials for this and I'm not doing anything different from them. If you have a moment, could you take a look and see if there's something wrong that catches your eye? Thanks!

 

@SidedProxy(clientSide = "com.aurelios.client.ClientProxy", serverSide = "com.aurelios.server.ServerProxy")
    public static IProxy proxy;

    @Listener
    public void onGamePreInit(GamePreInitializationEvent event){
        AureliosPacketHandler.init();

        proxy.preInit();
    }

This is a SpongeForge mod (hence why I'm using GamePreInitializationEvent). For clarity, I did cast GamePreInitializationEvent to FMLPreInitializationEvent and the cast didn't fail, so I think it's safe to assume they are the same thing (or rather an extension of the FML event). And attached is my project structure, so that you can see I have the annotation pointing to the correct classes.

 

Also, I just noticed your name. If you're the Jabelar that wrote the tutorials on Blogspot, thanks for doing that! I have everyone of those bookmarked. They have and definitely will continue to come in handy!

Edited March 23, 2018 by Jimmeh

[jabelar]

I don't really think the GamePreIntializationEvent is an extention of FMLPreInitializationEvent because the source for GamePreIntializationEvent shows that it extends GameEvent which extends Event (and this Event class is a Sponge-specific one).

 

I'm guessing that somehow this event is posted before the proxy annotation is processed, because otherwise the value of proxy should have been properly injected. Or do you get any warning in your console log like a class not found related to the proxy?

[Jimmeh]

9 hours ago, jabelar said:

I don't really think the GamePreIntializationEvent is an extention of FMLPreInitializationEvent because the source for GamePreIntializationEvent shows that it extends GameEvent which extends Event (and this Event class is a Sponge-specific one).

 

I'm guessing that somehow this event is posted before the proxy annotation is processed, because otherwise the value of proxy should have been properly injected. Or do you get any warning in your console log like a class not found related to the proxy?

Your assumption was correct. I should've noticed that about the Sponge event. It works just fine using the FML events. Well, that'll do for my questions right now. Thanks for all the help! It's appreciated!