How do I move an item in inventory from cell X to cell Y?
How do I move an item from Inventory X to Box Y of an open chest?
I'm thinking of using the Robot class, i.e. Simulate clicking the mouse buttons, but then you need to know the coordinates of the cells. I do not know how to get them.

I tried to understand the source code of the Inventory Tweaks mod, but I did not understand how it works. It seems, too, with the help of simulation

Please clarify: What exactly are you trying to acheive. What do you mean by "move an item in inventory". Are you making a custom inventory, an addon for inventory tweaks or perhaps even something totally different?

Example:
I have potatoes in the inventory in cell X.
My task is to move the potatoes from cell X to cell Y.
The inventory is standard, you just need to move items in it. From one cell to another.

 

It is important that all actions should take place only on the client side

 

get the stack in slot X with inventory#getStackInSlot(X);

COPY THE STACK

set the stack with inventory#setStackInSlot(Y, copyOfX);

clear the old stack in slot X with inventory#setStackInSlot(X, ItemStack.EMPTY.copy())

 

Make sure to do additional checking king to make sure the itemstack can fit/is allowed to be in that slot etc.

Take a look at Container#transferStackInSlot

You don't need to clone the empty stack.

2 minutes ago, Draco18s said:

You don't need to clone the empty stack.

What if some code modifys that stack? Like merges it with a stack that isn’t empty? Won’t that modify ItemStack.EMPTY then?

4 minutes ago, Cadiboo said:

What if some code modifys that stack? Like merges it with a stack that isn’t empty? Won’t that modify ItemStack.EMPTY then?

You can't. ItemStack.EMPTY is meant to be immutable. That's why its a static reference and named the way its named.

 

Its item is Air (and you can't change a stack's item) and Air is always empty.

49 minutes ago, Draco18s said:

You can't. ItemStack.EMPTY is meant to be immutable. That's why its a static reference and named the way its named.

 

Its item is Air (and you can't change a stack's item) and Air is always empty.

Isn’t it’s item null? Point taken that you can’t change the item though

9 hours ago, Cadiboo said:

Isn’t it’s item null?

That it is, but null has always been Minecraft's air. Block.AIR was null at one point too.

10 hours ago, Cadiboo said:

get the stack in slot X with inventory#getStackInSlot(X);

COPY THE STACK

set the stack with inventory#setStackInSlot(Y, copyOfX);

clear the old stack in slot X with inventory#setStackInSlot(X, ItemStack.EMPTY.copy())

 

As I understand it, this will not work?

Just now, NoName_ said:

As I understand it, this will not work?

And why do you think that?

I don't know. So it will be?))

Will it  work on the client side?

    Minecraft.getMinecraft().player.inventory.setInventorySlotContents(0, Minecraft.getMinecraft().player.inventory.getStackInSlot(i).copy());
    Minecraft.getMinecraft().player.inventory.setInventorySlotContents(i, ItemStack.EMPTY);

It does not work on a server. A server does not know that I moved the item. I understand me need to use the exchange of packages?

 

Edited October 1, 20186 yr by NoName_

4 minutes ago, NoName_ said:

    Minecraft.getMinecraft().player.inventory.setInventorySlotContents(0, Minecraft.getMinecraft().player.inventory.getStackInSlot(i).copy());
    Minecraft.getMinecraft().player.inventory.setInventorySlotContents(i, ItemStack.EMPTY);

That's because your using client-side only code.

 

5 minutes ago, NoName_ said:

need to use the exchange of packages?

What is "exchange of packets"?

From a user perspective, when do you want this to happen in the inventory? 

4 minutes ago, larsgerrits said:

What is "exchange of packets"?

Packets? I do not know how to properly call it. (NetHandlerPlayClient  and NetHandlerPlayServer)

4 minutes ago, larsgerrits said:

From a user perspective, when do you want this to happen in the inventory? 

I need a method that changes the place of an item in the inventory.
I do with the example of a hoe. I'm looking for a hoe in the inventory, when I found it, I move it to the first location of the inventory.

 

for (int i = 1; i < 36; i++) {
    if(Minecraft.getMinecraft().player.inventory.getStackInSlot(i).getItem() instanceof ItemHoe){
        Minecraft.getMinecraft().player.inventory.setInventorySlotContents(0, Minecraft.getMinecraft().player.inventory.getStackInSlot(i).copy());
        Minecraft.getMinecraft().player.inventory.setInventorySlotContents(i, ItemStack.EMPTY);
        break;
    }
}

I recommend placing some breakpoints, manually doing this & seeing what methods get called. Some breakpoints in CPackets and the CLIENTSIDE containers (as your making a client side mod) would be a good place to start. Make sure that your not looking at the servers handling when debugging

And with "from a user perspective" I meant: what should the user to do run this action? For example: the user presses a key or clicks a button in a GUI.

User does not do anything. The mod itself under certain circumstances moves the item in the inventory. 

What are the circumstances

14 hours ago, Cadiboo said:

What are the circumstances

For example, if the tool breaks. 
Why is it important?

8 minutes ago, NoName_ said:

For example, if the tool breaks. 
Why is it important?

What version are you doing this for? And is this only for the client?

1 minute ago, Animefan8888 said:

What version are you doing this for? And is this only for the client?

1.12.2 

Yes, only on the client, because it is necessary for the mod to work on other servers

2 minutes ago, NoName_ said:

1.12.2 

Yes, only on the client, because it is necessary for the mod to work on other servers

And why not just use Inventory Tweaks? It has the same feature you are requesting from us.

1 minute ago, Animefan8888 said:

And why not just use Inventory Tweaks? It has the same feature you are requesting from us.

I do not understand how it works. This is not good. Besides, why add the whole mod if I need one function. In addition, it would not be bad to understand this issue.

1 minute ago, NoName_ said:

I do not understand how it works. This is not good. In addition, it would not be bad to understand this issue.

What you need to do from your original implementation is let the server know that you changed them.

 

3 minutes ago, NoName_ said:

Besides, why add the whole mod if I need one function. 

Because that one function is already done and the inventory sorting function is a god send.