Hi,

I have implemented custom chest, but I am getting a very strange error when the menu should appear.

This is how menu is registered:

public final class ContainerMenuTypes {

	private ContainerMenuTypes() {}
	
	public static final DeferredRegister<MenuType<?>> REGISTRY =
			DeferredRegister.create(ForgeRegistries.MENU_TYPES, ExperimentalMod.MODID);
	
	public static final RegistryObject<MenuType<VikingChestMenu>> VIKING_CHEST =
			REGISTRY.register("viking_chest", () -> IForgeMenuType.create(VikingChestMenu::new));

}

 

And this is how constructor looks like:

	// This constructor is required by forge to register menu type.
	public VikingChestMenu(int containerId, Inventory inventory, FriendlyByteBuf buff) {
		this(containerId, inventory, inventory.player.level.getBlockEntity(buff.readBlockPos()));
	}

 

So when I click on the chest, this error occurs:

 

[15:31:15] [Render thread/ERROR] [minecraft/BlockableEventLoop]: Error executing task on Client
java.lang.NullPointerException: Cannot invoke "net.minecraft.network.FriendlyByteBuf.readBlockPos()" because "buff" is null
	at ba.appimpact.minecraft.experimental.common.menu.container.VikingChestMenu.<init>(VikingChestMenu.java:83) ~[%23186!/:?] {re:classloading}
	at net.minecraftforge.network.IContainerFactory.create(IContainerFactory.java:20) ~[forge-1.19-41.0.110_mapped_parchment_1.18.2-2022.07.17-1.19.jar%23180%23187!/:?] {re:classloading}
	at net.minecraft.world.inventory.MenuType.create(MenuType.java:44) ~[forge-1.19-41.0.110_mapped_parchment_1.18.2-2022.07.17-1.19.jar%23181!/:?] {re:classloading,pl:accesstransformer:B}
	at net.minecraft.client.gui.screens.MenuScreens$ScreenConstructor.fromPacket(MenuScreens.java:115) ~[forge-1.19-41.0.110_mapped_parchment_1.18.2-2022.07.17-1.19.jar%23181!/:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
	at net.minecraft.client.gui.screens.MenuScreens.lambda$create$0(MenuScreens.java:43) ~[forge-1.19-41.0.110_mapped_parchment_1.18.2-2022.07.17-1.19.jar%23181!/:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
	at java.util.Optional.ifPresent(Optional.java:178) ~[?:?] {}
	at net.minecraft.client.gui.screens.MenuScreens.create(MenuScreens.java:43) ~[forge-1.19-41.0.110_mapped_parchment_1.18.2-2022.07.17-1.19.jar%23181!/:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
	at net.minecraft.client.multiplayer.ClientPacketListener.handleOpenScreen(ClientPacketListener.java:979) ~[forge-1.19-41.0.110_mapped_parchment_1.18.2-2022.07.17-1.19.jar%23181!/:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
	at net.minecraft.network.protocol.game.ClientboundOpenScreenPacket.handle(ClientboundOpenScreenPacket.java:37) ~[forge-1.19-41.0.110_mapped_parchment_1.18.2-2022.07.17-1.19.jar%23181!/:?] {re:classloading}
	at net.minecraft.network.protocol.game.ClientboundOpenScreenPacket.handle(ClientboundOpenScreenPacket.java:11) ~[forge-1.19-41.0.110_mapped_parchment_1.18.2-2022.07.17-1.19.jar%23181!/:?] {re:classloading}
	at net.minecraft.network.protocol.PacketUtils.lambda$ensureRunningOnSameThread$0(PacketUtils.java:22) ~[forge-1.19-41.0.110_mapped_parchment_1.18.2-2022.07.17-1.19.jar%23181!/:?] {re:classloading}
	at net.minecraft.util.thread.BlockableEventLoop.doRunTask(BlockableEventLoop.java:157) ~[forge-1.19-41.0.110_mapped_parchment_1.18.2-2022.07.17-1.19.jar%23181!/:?] {re:classloading,pl:accesstransformer:B}
	at net.minecraft.util.thread.ReentrantBlockableEventLoop.doRunTask(ReentrantBlockableEventLoop.java:23) ~[forge-1.19-41.0.110_mapped_parchment_1.18.2-2022.07.17-1.19.jar%23181!/:?] {re:classloading}
	at net.minecraft.util.thread.BlockableEventLoop.pollTask(BlockableEventLoop.java:131) ~[forge-1.19-41.0.110_mapped_parchment_1.18.2-2022.07.17-1.19.jar%23181!/:?] {re:classloading,pl:accesstransformer:B}
	at net.minecraft.util.thread.BlockableEventLoop.runAllTasks(BlockableEventLoop.java:116) ~[forge-1.19-41.0.110_mapped_parchment_1.18.2-2022.07.17-1.19.jar%23181!/:?] {re:classloading,pl:accesstransformer:B}
	at net.minecraft.client.Minecraft.runTick(Minecraft.java:1041) ~[forge-1.19-41.0.110_mapped_parchment_1.18.2-2022.07.17-1.19.jar%23181!/:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
	at net.minecraft.client.Minecraft.run(Minecraft.java:669) ~[forge-1.19-41.0.110_mapped_parchment_1.18.2-2022.07.17-1.19.jar%23181!/:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
	at net.minecraft.client.main.Main.main(Main.java:206) ~[forge-1.19-41.0.110_mapped_parchment_1.18.2-2022.07.17-1.19.jar%23181!/:?] {re:classloading,pl:runtimedistcleaner:A}
	at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:?] {}
	at jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77) ~[?:?] {}
	at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:?] {}
	at java.lang.reflect.Method.invoke(Method.java:568) ~[?:?] {}
	at net.minecraftforge.fml.loading.targets.ForgeClientUserdevLaunchHandler.lambda$launchService$0(ForgeClientUserdevLaunchHandler.java:25) ~[fmlloader-1.19-41.0.110.jar%2394!/:?] {}
	at cpw.mods.modlauncher.LaunchServiceHandlerDecorator.launch(LaunchServiceHandlerDecorator.java:30) [modlauncher-10.0.8.jar%23106!/:?] {}
	at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:53) [modlauncher-10.0.8.jar%23106!/:?] {}
	at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:71) [modlauncher-10.0.8.jar%23106!/:?] {}
	at cpw.mods.modlauncher.Launcher.run(Launcher.java:106) [modlauncher-10.0.8.jar%23106!/:?] {}
	at cpw.mods.modlauncher.Launcher.main(Launcher.java:77) [modlauncher-10.0.8.jar%23106!/:?] {}
	at cpw.mods.modlauncher.BootstrapLaunchConsumer.accept(BootstrapLaunchConsumer.java:26) [modlauncher-10.0.8.jar%23106!/:?] {}
	at cpw.mods.modlauncher.BootstrapLaunchConsumer.accept(BootstrapLaunchConsumer.java:23) [modlauncher-10.0.8.jar%23106!/:?] {}
	at cpw.mods.bootstraplauncher.BootstrapLauncher.main(BootstrapLauncher.java:141) [bootstraplauncher-1.1.2.jar:?] {}

 

For some reason, FriendlyByteBuf buff is null in constructor and I need it to access block entity so that rest of the code can execute.

Any ideas what could be wrong here?

 

Please show the code where you open the menu.

This is the use method on VikingChestBlock class:

	@Override
	public InteractionResult use(BlockState blockState, Level level, BlockPos blockPos, Player player, InteractionHand hand, BlockHitResult blockHitResult) {
		
		// IF: Code is executing on logical client.
		if(level.isClientSide) {
			// Do nothing.
			return InteractionResult.SUCCESS;
		}
		
		// Get block entity at the position where block was used.
		BlockEntity blockEntity = level.getBlockEntity(blockPos);
		
        if (blockEntity instanceof VikingChestBlockEntity) {

        	// Open menu.
			player.openMenu((VikingChestBlockEntity)blockEntity);
			
         }
		
		return InteractionResult.CONSUME;
	}

 

I also used this, but didn't work either:

 

@Override
	public InteractionResult use(BlockState blockState, Level level, BlockPos blockPos, Player player, InteractionHand hand, BlockHitResult blockHitResult) {
		
		// IF: Code is executing on logical client.
		if(level.isClientSide) {
			// Do nothing.
			return InteractionResult.SUCCESS;
		}
		
		// Get menu provider reference.
		MenuProvider menuprovider = this.getMenuProvider(blockState, level, blockPos);

		// IF: Menu provider is defined.
		if (menuprovider != null) {
			
			// Open menu.
			player.openMenu(menuprovider);
			
		}

		return InteractionResult.CONSUME;
	}

 

 

Thanks @diesieben07 and @Luis_ST, you've helped me a lot as usual.

 

It works great now with this code:

 

@Override
      public InteractionResult use(BlockState blockState, Level level, BlockPos blockPos, Player player, InteractionHand hand, BlockHitResult blockHitResult) {
		
		// IF: Code is executing on logical client.
		if(level.isClientSide) {
			// Do nothing.
			return InteractionResult.SUCCESS;
		}
		
		// Get block entity at the block location.
		BlockEntity blockEntity = level.getBlockEntity(blockPos);
		
		// IF: block entity is matching.
		if (blockEntity instanceof VikingChestBlockEntity) {
			
			// Cast player to ServerPlayer.
			ServerPlayer serverPlayer = (ServerPlayer) player;
			
			// Cast block entity to VikingChestBlockEntity.
			VikingChestBlockEntity vikingChestBlockEntity = (VikingChestBlockEntity)blockEntity;

			// Open menu.
            NetworkHooks.openScreen(serverPlayer, vikingChestBlockEntity, blockPos);
		}

		return InteractionResult.CONSUME;
	}