[1.12.2]Set mouse itemstack in gui

[WOTBLITZ]

I was making a mod that sets an item on the mouse and I was testing everything in creative mode. When I tested it on survival mode the item stack was like it was only added in client side(you can't use the item it would disappear) but it worked just fine in creative.

 

Here is the code*:

 

public static void setMouseItem(ItemStack stack)
{
	getPlayerServer().inventory.setItemStack(stack);
	getPlayerClient().inventory.setItemStack(stack);
}

public static EntityPlayer getPlayerClient()
{
	return Minecraft.getMinecraft().player;
}

public static EntityPlayer getPlayerServer()
{
	return FMLCommonHandler.instance().getMinecraftServerInstance().getPlayerList().getPlayerByUsername(getPlayerClient().getName());
}

 

*The code was based on an old discontinued mod.

Edited February 10, 2018 by WOTBLITZ

[Draco18s]

You're reaching across logical sides here. You can't do this, as as soon as you connect to a dedicated server, it wil. crash (because on the client FMLCommonHandler.instance().getMinecraftServerInstance() will be null).

 

You must use packets for this. The reason it works in creative, is because in creative the server explicitly allows the client to alter their own inventory. In survival, this is expressly forbidden.

[WOTBLITZ]

No, it is not null. Did this work on an older version of mc? And as I said before "The code was based on an old discontinued mod" and that did not use packets. However, I will use packets.

[Draco18s]

This is client side only and will absolutely crash a dedicated server:

public static EntityPlayer getPlayerClient()
{
	return Minecraft.getMinecraft().player;
}

This is server side only:

public static EntityPlayer getPlayerServer()
{
    return FMLCommonHandler.instance().getMinecraftServerInstance().getPlayerList().getPlayerByUsername(...);
}

As evidenced by the "get server instance" method name.

 

This code could only ever work single player, which is why it's called "reaching across logical sides."

Edited February 10, 2018 by Draco18s

[WOTBLITZ]

FMLCommonHandler.instance().getMinecraftServerInstance() seems to work. I can't see the item but closing the inventory will drop the item. Just a note.

[Draco18s]

On 2/8/2018 at 1:10 AM, diesieben07 said:

No, what you are doing is known as reaching across logical sides and it is a very bad idea. This will crash as soon as you play on a server and it will cause random inexplicable crashes during normal single player gameplay.

 

[lyn mimistrobell]

3 hours ago, WOTBLITZ said:

FMLCommonHandler.instance().getMinecraftServerInstance() seems to work. I can't see the item but closing the inventory will drop the item. Just a note.

Are you playing on a multiplayer server or just a singleplayer instance?