Posted September 7, 201411 yr Hello, I need tot be able to spawn an entity with existing nbt data. When I try to do this it crashes and says that it is a null pointer exception. More info: Basically I have a tile entity that scans for a random entity around it, and it saves that entity in its self. It then kills the entity and on game exit it saves the entity nbt by using these lines of code: NBTTagCompound compound2 = new NBTTagCompound(); compound2.setString("id", EntityList.getEntityString(this.capturedEntity)); this.capturedEntity.writeToNBT(compound2); compound.setTag("EntityData", compound2); Then when I load it I use these lines of code: NBTTagCompound compound2 = (NBTTagCompound) compound.getTag("EntityData"); if(compound2 != null) { this.targetEntity = (EntityLiving) EntityList.createEntityFromNBT(compound2, this.worldObj); this.capturedEntity = this.targetEntity; } I tried printing the compound2 var and the entity obj out and they seem to display normal data, but when I try to spawn the entity in the world it crashes ans says that is is a Null Pointer Exception. Full Code: package mod.xtronius.htsm.tileEntity; import java.util.ArrayList; import java.util.List; import mod.xtronius.htsm.entity.ai.EntityAIGoToCage; import net.minecraft.block.Block; import net.minecraft.entity.Entity; import net.minecraft.entity.EntityList; import net.minecraft.entity.EntityLiving; import net.minecraft.entity.ai.EntityAITempt; import net.minecraft.entity.passive.EntityPig; import net.minecraft.entity.player.EntityPlayer; import net.minecraft.init.Items; import net.minecraft.inventory.IInventory; import net.minecraft.item.Item; import net.minecraft.item.ItemStack; import net.minecraft.nbt.NBTTagCompound; import net.minecraft.nbt.NBTTagList; import net.minecraft.tileentity.TileEntity; import net.minecraft.util.AxisAlignedBB; public class TileEntityCage extends TileEntity implements IInventory{ private ItemStack[] cageContents = new ItemStack[3]; private boolean isCageClosed = false; private EntityLiving targetEntity; private EntityLiving capturedEntity; private ArrayList<Entity> removedEntities = new ArrayList<Entity>(); private int timer = 0; @Override public void updateEntity() { if(!this.worldObj.isRemote) { float seconds = 1.5f; int delay = (int) (seconds * 20); if(timer <= delay) timer++; else timer = 0; // this.targetEntity = null; // this.capturedEntity = null; // this.isCageClosed = false; //TODO Remove test code // System.out.println("Target: " + targetEntity); // System.out.println("Capture: " + capturedEntity); // System.out.println("IsClosed: " + isCageClosed); if(timer == delay) { //Checks to see if the inv slots are filled if(this.getStackInSlot(0) != null && this.getStackInSlot(1) != null && this.getStackInSlot(2) != null && !this.isCageClosed) { //TODO Create an item stack array for checking specific items //Gets the block at the tile entities' postion Block block = this.worldObj.getBlock(this.xCoord, this.yCoord, this.zCoord); //Gets the bounding box of the block obtained above, then it offsets it and expands it AxisAlignedBB aabb = AxisAlignedBB.getBoundingBox(block.getBlockBoundsMinX(), block.getBlockBoundsMinY(), block.getBlockBoundsMinZ(), block.getBlockBoundsMaxX(), block.getBlockBoundsMaxY(), block.getBlockBoundsMaxZ()); AxisAlignedBB aabb1 = aabb.getOffsetBoundingBox(this.xCoord, this.yCoord, this.zCoord); AxisAlignedBB aabb2 = aabb1.expand(10, 10, 10); //Gets all entities within this bounding box List<EntityPig> list = this.worldObj.getEntitiesWithinAABB(EntityPig.class, aabb2); for(EntityPig entity : list) { // Breaks if the cage is closed, if the entity is already in another list or if there is already a targeted entity; if(isCageClosed || this.targetEntity != null || this.capturedEntity != null) break; if(!this.removedEntities.contains(entity)) { //Math for calculating the percentage chance double rand = Math.random(); double randPercent = rand < 0.75 ? rand : 0.75; double item = 1.0; double subPercent = (item * randPercent) < 1.0 ? (item * randPercent) : 1.0; double finalPercent = 1 - subPercent; double rand2 = Math.random(); //TODO Remove test code //Test Code // double rand2 = 1; if(rand2 > finalPercent) { //Try to send the entity to the tile entities location, closes the gate and set the entity as the target entity System.out.println("Working"); entity.getNavigator().tryMoveToXYZ(this.xCoord, yCoord, zCoord, 1.0f); this.isCageClosed = true; this.targetEntity = entity; break; } else { this.removedEntities.add(entity); System.out.println("Fail"); } } } } else if(this.isCageClosed) { int range = 3; if(this.targetEntity != null) { if(this.targetEntity.posX > this.xCoord - range && this.targetEntity.posX < this.xCoord + range) { if(this.targetEntity.posY > this.yCoord - range && this.targetEntity.posY < this.yCoord + range) { if(this.targetEntity.posZ > this.zCoord - range && this.targetEntity.posZ < this.zCoord + range) { this.capturedEntity = this.targetEntity; } else if(this.targetEntity != null) ((EntityPig) this.targetEntity).getNavigator().tryMoveToXYZ(this.xCoord, yCoord, zCoord, 1.0f); } else if(this.targetEntity != null) ((EntityPig) this.targetEntity).getNavigator().tryMoveToXYZ(this.xCoord, yCoord, zCoord, 1.0f); } else if(this.targetEntity != null) ((EntityPig) this.targetEntity).getNavigator().tryMoveToXYZ(this.xCoord, yCoord, zCoord, 1.0f); } // //Checks if the targeted entity is not alive, if so then reset the main variables // if(this.capturedEntity != null) // if(this.capturedEntity.isDead) resetVars(); // // //Checks if the captured entity is not alive, if so then reset the main variables // if(this.capturedEntity != null) // if(this.capturedEntity.isDead) resetVars(); } } } } private void resetVars() { this.isCageClosed = false; this.targetEntity = null; this.capturedEntity = null; } @Override public void readFromNBT(NBTTagCompound compound) { super.readFromNBT(compound); NBTTagList list = compound.getTagList("Items", 10); this.cageContents = new ItemStack[this.getSizeInventory()]; for (int i = 0; i < list.tagCount(); ++i) { NBTTagCompound compound1 = list.getCompoundTagAt(i); int j = compound1.getByte("Slot") & 255; if (j >= 0 && j < this.cageContents.length) { this.cageContents[j] = ItemStack.loadItemStackFromNBT(compound1); } } NBTTagCompound compound2 = (NBTTagCompound) compound.getTag("EntityData"); if(compound2 != null) { this.targetEntity = (EntityLiving) EntityList.createEntityFromNBT(compound2, this.worldObj); this.capturedEntity = this.targetEntity; } if(this.capturedEntity != null) { this.isCageClosed = true; } } @Override public void writeToNBT(NBTTagCompound compound) { super.writeToNBT(compound); NBTTagList list = new NBTTagList(); for (int i = 0; i < this.cageContents.length; ++i) { if (this.cageContents[i] != null) { NBTTagCompound compound1 = new NBTTagCompound(); compound1.setByte("Slot", (byte)i); this.cageContents[i].writeToNBT(compound1); list.appendTag(compound1); } } compound.setTag("Items", list); if(this.capturedEntity != null) { NBTTagCompound compound2 = new NBTTagCompound(); compound2.setString("id", EntityList.getEntityString(this.capturedEntity)); this.capturedEntity.writeToNBT(compound2); compound.setTag("EntityData", compound2); } } @Override public int getSizeInventory() { return 3; } @Override public ItemStack getStackInSlot(int slot) { return this.cageContents[slot]; } @Override public ItemStack decrStackSize(int p_70298_1_, int p_70298_2_) { if (this.cageContents[p_70298_1_] != null) { ItemStack itemstack; if (this.cageContents[p_70298_1_].stackSize <= p_70298_2_) { itemstack = this.cageContents[p_70298_1_]; this.cageContents[p_70298_1_] = null; this.markDirty(); return itemstack; } else { itemstack = this.cageContents[p_70298_1_].splitStack(p_70298_2_); if (this.cageContents[p_70298_1_].stackSize == 0) { this.cageContents[p_70298_1_] = null; } this.markDirty(); return itemstack; } } else { return null; } } @Override public ItemStack getStackInSlotOnClosing(int slot) { return this.cageContents[slot]; } @Override public void setInventorySlotContents(int slot, ItemStack stack) { this.cageContents[slot] = stack; } @Override public String getInventoryName() { return "Cage"; } @Override public boolean hasCustomInventoryName() { return false; } @Override public int getInventoryStackLimit() { return 64; } @Override public boolean isUseableByPlayer(EntityPlayer player) { return this.worldObj.getTileEntity(this.xCoord, this.yCoord, this.zCoord) != this ? false : player.getDistanceSq((double)this.xCoord + 0.5D, (double)this.yCoord + 0.5D, (double)this.zCoord + 0.5D) <= 64.0D; } @Override public void openInventory() {} @Override public void closeInventory() {} @Override public boolean isItemValidForSlot(int slot, ItemStack stack) { return true; } } Don't be afraid to ask question when modding, there are no stupid question! Unless you don't know java then all your questions are stupid!
September 8, 201411 yr Could you post your crash log? Check out my blog! http://www.whov.altervista.org
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.