Sup! I'm so sorry for asking questuions so often.
Now Im stydying how to work with capabilities and netwrok. I have a cap which contains some int id. It changes in custom menu. I want to synchronize it with other players, but so far it hasn't worked. Could someone who knows me give me an idea or tell me how to implement it.

 

public class UpdateCapPacket extends AbstractMessage<UpdateCapPacket> {

    private int hatId;

    public UpdateCapPacket() {

    }

    public UpdateCapPacket(int id) {
        this.hatId = id;
    }

    @Override
    public void encode(UpdateCapPacket message, PacketBuffer buffer) {
        buffer.writeInt(message.hatId);
    }

    @Override
    public UpdateCapPacket decode(PacketBuffer buffer) {
        int id = buffer.readInt();
        return new UpdateCapPacket(hatId);
    }

    @Override
    public void handle(UpdateCapPacket message, Supplier<NetworkEvent.Context> ctx) {
        if (ctx.get().getDirection().getReceptionSide() == LogicalSide.CLIENT)
            ctx.get().enqueueWork(() ->
            {
                InfCust.LOGGER.error("[UPDATING CAP PACKET]");
                final Optional<World> optionalWorld = LogicalSidedProvider.CLIENTWORLD.get(ctx.get().getDirection().getReceptionSide());
                final LivingEntity livingEntity = ctx.get().getSender();
                if (livingEntity != null) {
                  // Living entity is always null, whats wrong 
                    InfCust.LOGGER.error("[CHANGING CAP]");
                    optionalWorld.ifPresent(world -> InfCust.capabilityUtil.updateCapabilityHatId(message.hatId));
                }
                InfCust.LOGGER.error(InfCust.capabilityUtil.getCapabilityHatId());
            });
        ctx.get().setPacketHandled(true);
    }
}

public void OpenCustMenu() {
        // For example
        Minecraft.getInstance().setScreen(new CustomizationScreen());
        PacketDispatcher.sendToAll(new UpdateCapPacket(-1));
    }

 

4 hours ago, diesieben07 said:

This makes zero sense in a server side packet.

What is this? You must obtain the capability from the player, you can't just put it in a static field somewhere.

CapabilityUtil

 

public void updateCapabilityHatId(int id)
    {
        ClientPlayerEntity player = Minecraft.getInstance().player;
        player.getCapability(HatCapability.PLAYER_HAT_ID).ifPresent((Data) -> Data.setValue(id));
    }

    public int getCapabilityHatId()
    {
        ClientPlayerEntity player = Minecraft.getInstance().player;
        if (player != null) {
            int id = player.getCapability(HatCapability.PLAYER_HAT_ID)
                    .map(capa -> capa.getValue())
                    .orElse(0);
            return id;
        }
        else return -1;

    }

Something like a helper to me.

So how can I make this packet correctly. Sorry for the question, I'm just starting to understand this whole topic and don't understand how exactly to make this packet

Huh, understand. I think I can get by ctx.get().getSender().getId();
But, how correctly I have to work with this id? If it's not difficult for you, could you show or tell how exactly I should contact the player by his id in my packet?

Huh, why does ctx.get().getSender().getId() returns null, If I send my packet to all

So, im trying to make updating system with id, first of all I wanted to see this id, but

This is my handle code and error message

@Override
    public void handle(UpdateCapPacket message, Supplier<NetworkEvent.Context> ctx) {
        if (ctx.get().getDirection().getReceptionSide() == LogicalSide.CLIENT) {
            ctx.get().enqueueWork(() ->
            {
                InfCust.LOGGER.error("[UPDATING CAP PACKET]");
                InfCust.LOGGER.error(ctx.get().getSender().getId());
            });
            ctx.get().setPacketHandled(true);
        }
    }

[23:12:09] [Render thread/FATAL] [minecraft/ThreadTaskExecutor]: Error executing task on Client
java.lang.NullPointerException: null
	at net.minecraftforge.fml.LogicalSidedProvider.lambda$static$3(LogicalSidedProvider.java:33) ~[forge-1.16.5-36.2.29_mapped_official_1.16.5-recomp.jar:?] {re:classloading}
	at net.minecraftforge.fml.LogicalSidedProvider.get(LogicalSidedProvider.java:60) ~[forge-1.16.5-36.2.29_mapped_official_1.16.5-recomp.jar:?] {re:classloading}
	at net.minecraftforge.fml.network.PacketDistributor.getServer(PacketDistributor.java:264) ~[forge-1.16.5-36.2.29_mapped_official_1.16.5-recomp.jar:?] {re:classloading}
	at net.minecraftforge.fml.network.PacketDistributor.lambda$playerListAll$3(PacketDistributor.java:224) ~[forge-1.16.5-36.2.29_mapped_official_1.16.5-recomp.jar:?] {re:classloading}
	at net.minecraftforge.fml.network.PacketDistributor$PacketTarget.send(PacketDistributor.java:179) ~[forge-1.16.5-36.2.29_mapped_official_1.16.5-recomp.jar:?] {re:classloading}
	at net.minecraftforge.fml.network.simple.SimpleChannel.send(SimpleChannel.java:124) ~[forge-1.16.5-36.2.29_mapped_official_1.16.5-recomp.jar:?] {re:classloading}
	at com.feedoktv.infcust.common.core.networking.PacketDispatcher.sendToAll(PacketDispatcher.java:66) ~[main/:?] {re:classloading}
	at com.feedoktv.infcust.client.handlers.EventHandlerClient.OpenCustMenu(EventHandlerClient.java:82) ~[main/:?] {re:classloading}
	at com.feedoktv.infcust.common.core.networking.packets.OpenMainMenuPacket.lambda$handle$0(OpenMainMenuPacket.java:26) ~[main/:?] {re:classloading}
	at net.minecraftforge.fml.network.NetworkEvent$Context.enqueueWork(NetworkEvent.java:215) ~[forge-1.16.5-36.2.29_mapped_official_1.16.5-recomp.jar:?] {re:classloading}
	at com.feedoktv.infcust.common.core.networking.packets.OpenMainMenuPacket.handle(OpenMainMenuPacket.java:23) ~[main/:?] {re:classloading}
	at com.feedoktv.infcust.common.core.networking.packets.OpenMainMenuPacket.handle(OpenMainMenuPacket.java:10) ~[main/:?] {re:classloading}
	at net.minecraftforge.fml.network.simple.IndexedMessageCodec.lambda$tryDecode$3(IndexedMessageCodec.java:128) ~[forge-1.16.5-36.2.29_mapped_official_1.16.5-recomp.jar:?] {re:classloading}
	at java.util.Optional.ifPresent(Optional.java:159) ~[?:1.8.0_311] {}
	at net.minecraftforge.fml.network.simple.IndexedMessageCodec.tryDecode(IndexedMessageCodec.java:128) ~[forge-1.16.5-36.2.29_mapped_official_1.16.5-recomp.jar:?] {re:classloading}
	at net.minecraftforge.fml.network.simple.IndexedMessageCodec.consume(IndexedMessageCodec.java:162) ~[forge-1.16.5-36.2.29_mapped_official_1.16.5-recomp.jar:?] {re:classloading}
	at net.minecraftforge.fml.network.simple.SimpleChannel.networkEventListener(SimpleChannel.java:80) ~[forge-1.16.5-36.2.29_mapped_official_1.16.5-recomp.jar:?] {re:classloading}
	at net.minecraftforge.eventbus.EventBus.doCastFilter(EventBus.java:247) ~[eventbus-4.0.0.jar:?] {}
	at net.minecraftforge.eventbus.EventBus.lambda$addListener$11(EventBus.java:239) ~[eventbus-4.0.0.jar:?] {}
	at net.minecraftforge.eventbus.EventBus.post(EventBus.java:302) ~[eventbus-4.0.0.jar:?] {}
	at net.minecraftforge.eventbus.EventBus.post(EventBus.java:283) ~[eventbus-4.0.0.jar:?] {}
	at net.minecraftforge.fml.network.NetworkInstance.dispatch(NetworkInstance.java:86) ~[forge-1.16.5-36.2.29_mapped_official_1.16.5-recomp.jar:?] {re:classloading}
	at net.minecraftforge.fml.network.NetworkHooks.lambda$onCustomPayload$1(NetworkHooks.java:91) ~[forge-1.16.5-36.2.29_mapped_official_1.16.5-recomp.jar:?] {re:classloading}
	at java.util.Optional.map(Optional.java:215) ~[?:1.8.0_311] {}
	at net.minecraftforge.fml.network.NetworkHooks.onCustomPayload(NetworkHooks.java:91) ~[forge-1.16.5-36.2.29_mapped_official_1.16.5-recomp.jar:?] {re:classloading}
	at net.minecraft.client.network.play.ClientPlayNetHandler.handleCustomPayload(ClientPlayNetHandler.java:1904) ~[forge-1.16.5-36.2.29_mapped_official_1.16.5-recomp.jar:?] {re:classloading,pl:runtimedistcleaner:A}
	at net.minecraft.network.play.server.SCustomPayloadPlayPacket.handle(SCustomPayloadPlayPacket.java:59) ~[forge-1.16.5-36.2.29_mapped_official_1.16.5-recomp.jar:?] {re:classloading}
	at net.minecraft.network.play.server.SCustomPayloadPlayPacket.handle(SCustomPayloadPlayPacket.java:11) ~[forge-1.16.5-36.2.29_mapped_official_1.16.5-recomp.jar:?] {re:classloading}
	at net.minecraft.network.PacketThreadUtil.lambda$ensureRunningOnSameThread$0(PacketThreadUtil.java:19) ~[forge-1.16.5-36.2.29_mapped_official_1.16.5-recomp.jar:?] {re:classloading}
	at net.minecraft.util.concurrent.ThreadTaskExecutor.doRunTask(ThreadTaskExecutor.java:136) ~[forge-1.16.5-36.2.29_mapped_official_1.16.5-recomp.jar:?] {re:classloading,pl:accesstransformer:B}
	at net.minecraft.util.concurrent.RecursiveEventLoop.doRunTask(RecursiveEventLoop.java:22) ~[forge-1.16.5-36.2.29_mapped_official_1.16.5-recomp.jar:?] {re:classloading}
	at net.minecraft.util.concurrent.ThreadTaskExecutor.pollTask(ThreadTaskExecutor.java:109) ~[forge-1.16.5-36.2.29_mapped_official_1.16.5-recomp.jar:?] {re:classloading,pl:accesstransformer:B}
	at net.minecraft.util.concurrent.ThreadTaskExecutor.runAllTasks(ThreadTaskExecutor.java:97) ~[forge-1.16.5-36.2.29_mapped_official_1.16.5-recomp.jar:?] {re:classloading,pl:accesstransformer:B}
	at net.minecraft.client.Minecraft.runTick(Minecraft.java:948) ~[forge-1.16.5-36.2.29_mapped_official_1.16.5-recomp.jar:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
	at net.minecraft.client.Minecraft.run(Minecraft.java:607) ~[forge-1.16.5-36.2.29_mapped_official_1.16.5-recomp.jar:?] {re:classloading,pl:accesstransformer:B,pl:runtimedistcleaner:A}
	at net.minecraft.client.main.Main.main(Main.java:184) ~[forge-1.16.5-36.2.29_mapped_official_1.16.5-recomp.jar:?] {re:classloading,pl:runtimedistcleaner:A}
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_311] {}
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_311] {}
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_311] {}
	at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_311] {}
	at net.minecraftforge.userdev.FMLUserdevClientLaunchProvider.lambda$launchService$0(FMLUserdevClientLaunchProvider.java:52) ~[forge-1.16.5-36.2.29_mapped_official_1.16.5-recomp.jar:?] {}
	at cpw.mods.modlauncher.LaunchServiceHandlerDecorator.launch(LaunchServiceHandlerDecorator.java:37) [modlauncher-8.1.3.jar:?] {}
	at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:54) [modlauncher-8.1.3.jar:?] {}
	at cpw.mods.modlauncher.LaunchServiceHandler.launch(LaunchServiceHandler.java:72) [modlauncher-8.1.3.jar:?] {}
	at cpw.mods.modlauncher.Launcher.run(Launcher.java:82) [modlauncher-8.1.3.jar:?] {}
	at cpw.mods.modlauncher.Launcher.main(Launcher.java:66) [modlauncher-8.1.3.jar:?] {}
	at net.minecraftforge.userdev.LaunchTesting.main(LaunchTesting.java:108) [forge-1.16.5-36.2.29_mapped_official_1.16.5-recomp.jar:?] {}