[Solved][1.16.1]How do I add Player Capability

[kyazuki]

I want to add a float value to player.

 

This code always throws IllegalArgumentException("at login") at onloginPlayer() in Main Class.

I think attachCapability isn't called, but I don't know why it isn't.

 

Please tell me if I'm making any other errors in this code.

 

public class Scale implements IScale {
  private float scale;

  public Scale(float scale) {  this.scale = scale;  }

  @Override
  public void set(float scale) {  this.scale = scale;  }
  @Override
  public float get() {  return this.scale;  }
}

 

public class ScaleStorage implements Capability.IStorage<IScale> {
  @Override
  public INBT writeNBT(Capability<IScale> capability, IScale instance, Direction side) {
    return FloatNBT.valueOf(instance.get());
  }

  @Override
  public void readNBT(Capability<IScale> capability, IScale instance, Direction side, INBT nbt) {
    instance.set(((FloatNBT) nbt).getFloat());
  }
}

 

public class ScaleProvider implements ICapabilitySerializable<FloatNBT> {
  @CapabilityInject(IScale.class)
  public static final Capability<IScale> SCALE_CAP = null;

  private LazyOptional<IScale> instance = LazyOptional.of(SCALE_CAP::getDefaultInstance);

  @Nonnull
  @Override
  public <T> LazyOptional<T> getCapability(@Nonnull Capability<T> cap, @Nullable Direction side) {
    return SCALE_CAP.orEmpty(cap, instance);
  }

  @Override
  public FloatNBT serializeNBT() {
    return (FloatNBT) SCALE_CAP.getStorage().writeNBT(SCALE_CAP, instance.orElseThrow(() -> new IllegalArgumentException("at serialize")), null);
  }

  @Override
  public void deserializeNBT(FloatNBT nbt) {
    SCALE_CAP.getStorage().readNBT(SCALE_CAP, instance.orElseThrow(() -> new IllegalArgumentException("at deserialize")), null, nbt);
  }
}

 

Main Class:

@SubscribeEvent
  public void onFMLCommonSetup(FMLCommonSetupEvent event) {
    CapabilityManager.INSTANCE.register(IScale.class, new ScaleStorage(), () -> new Scale(2.0f));
  }

  @SubscribeEvent
  public void attachCapability(AttachCapabilitiesEvent<Entity> event) {
    if (!(event.getObject() instanceof PlayerEntity)) return;

    event.addCapability(SCALE_CAP, new ScaleProvider());
  }
  
  @SubscribeEvent
  public static void onloginPlayer(PlayerEvent.PlayerLoggedInEvent event) {
    PlayerEntity player = event.getPlayer();
    IScale p = player.getCapability(ScaleProvider.SCALE_CAP).orElseThrow(() -> new IllegalArgumentException("at login"));
    LOGGER.debug("check before: " + p.get());
    p.set(1.0f);
    LOGGER.debug("check after: " + p.get());
    LOGGER.debug(player.serializeNBT());
  }

 

Edited July 31, 2020 by kyazuki

[kyazuki]

Oh, I forget that.

  @SubscribeEvent
  public static void onFMLCommonSetup(FMLCommonSetupEvent event) {
    CapabilityManager.INSTANCE.register(IScale.class, new ScaleStorage(), () -> new Scale(2.0f));
  }

  @SubscribeEvent
  public static void attachCapability(AttachCapabilitiesEvent<Entity> event) {
    if (!(event.getObject() instanceof PlayerEntity)) return;

    event.addCapability(SCALE_CAP, new ScaleProvider());
  }

 

I changed code, but it throws a new error.

Quote

[Server thread/ERROR] [ne.mi.ev.EventBus/EVENTBUS]: Exception caught during firing event: null
    Index: 1
    Listeners:
        0: NORMAL
        1: ASM: class com.github.kyazuki.testmod.TestMod attachCapability(Lnet/minecraftforge/event/AttachCapabilitiesEvent;)V
java.lang.NullPointerException
    at com.github.kyazuki.testmod.capabilities.ScaleProvider.<init>(ScaleProvider.java:17)
    at com.github.kyazuki.testmod.TestMod.attachCapability(TestMod.java:72)
    at net.minecraftforge.eventbus.ASMEventHandler_24_TestMod_attachCapability_AttachCapabilitiesEvent.invoke(.dynamic)
    at net.minecraftforge.eventbus.ASMEventHandler.invoke(ASMEventHandler.java:80)
    at net.minecraftforge.eventbus.EventBus.post(EventBus.java:258)
    at net.minecraftforge.event.ForgeEventFactory.gatherCapabilities(ForgeEventFactory.java:569)
    at net.minecraftforge.event.ForgeEventFactory.gatherCapabilities(ForgeEventFactory.java:563)
    at net.minecraftforge.common.capabilities.CapabilityProvider.gatherCapabilities(CapabilityProvider.java:48)
    at net.minecraftforge.common.capabilities.CapabilityProvider.gatherCapabilities(CapabilityProvider.java:44)
    at net.minecraft.entity.Entity.<init>(Entity.java:224)
    at net.minecraft.entity.LivingEntity.<init>(LivingEntity.java:206)
    at net.minecraft.entity.player.PlayerEntity.<init>(PlayerEntity.java:159)
    at net.minecraft.entity.player.ServerPlayerEntity.<init>(ServerPlayerEntity.java:174)
    at net.minecraft.server.management.PlayerList.createPlayerForUser(PlayerList.java:415)
    at net.minecraft.network.login.ServerLoginNetHandler.tryAcceptPlayer(ServerLoginNetHandler.java:120)
    at net.minecraft.network.login.ServerLoginNetHandler.tick(ServerLoginNetHandler.java:64)
    at net.minecraft.network.NetworkManager.tick(NetworkManager.java:244)
    at net.minecraft.network.NetworkSystem.tick(NetworkSystem.java:150)
    at net.minecraft.server.MinecraftServer.updateTimeLightAndEntities(MinecraftServer.java:900)
    at net.minecraft.server.MinecraftServer.tick(MinecraftServer.java:822)
    at net.minecraft.server.integrated.IntegratedServer.tick(IntegratedServer.java:87)
    at net.minecraft.server.MinecraftServer.func_240802_v_(MinecraftServer.java:665)
    at net.minecraft.server.MinecraftServer.lambda$func_240784_a_$0(MinecraftServer.java:231)
    at java.lang.Thread.run(Thread.java:748)

What's wrong?

 

1 hour ago, kyazuki said:

 

public class ScaleProvider implements ICapabilitySerializable<FloatNBT> {
  @CapabilityInject(IScale.class)
  public static final Capability<IScale> SCALE_CAP = null;

  private LazyOptional<IScale> instance = LazyOptional.of(SCALE_CAP::getDefaultInstance); <-- throws NullPointerException

  @Nonnull
  @Override
  public <T> LazyOptional<T> getCapability(@Nonnull Capability<T> cap, @Nullable Direction side) {
    return SCALE_CAP.orEmpty(cap, instance);
  }

  @Override
  public FloatNBT serializeNBT() {
    return (FloatNBT) SCALE_CAP.getStorage().writeNBT(SCALE_CAP, instance.orElseThrow(() -> new IllegalArgumentException("at serialize")), null);
  }

  @Override
  public void deserializeNBT(FloatNBT nbt) {
    SCALE_CAP.getStorage().readNBT(SCALE_CAP, instance.orElseThrow(() -> new IllegalArgumentException("at deserialize")), null, nbt);
  }
}

 

 

 

[kyazuki]

I forgot to add listner...

public TestMod() {
  FMLJavaModLoadingContext.get().getModEventBus().addListener(TestMod::onFMLCommonSetup);
}

Thanks!

Edited July 31, 2020 by kyazuki