Hey everyone,

I'm trying to make a block give take the item that it's right-clicked with and give you back another one (for example, right click it with a diamond and you get an emerald). Surprisingly, this seems harder than it sounds. I know how to do something similar with items when they are right clicked like so:

public ItemStack onItemRightClick(ItemStack is, World world, EntityPlayer ep) {
--is.stackSize;
is = new ItemStack(Techcraft.unmagneticMagnet,1);
}

Hopefully I explained what I want to do well enough 

So far the block removes the currently held item but doesn't replace it. I have looked through vanilla code and nothing in there seems to have the same functionality (things like jukeboxes just take the item which I know how to do, and when you take the item out it puts it on the ground, not into the inventory).

Here's my code so far:

public boolean onBlockActivated(World world, int x, int y, int z, EntityPlayer player, int par6, float par7, float par8, float par9) {
	if (player.getHeldItem()!=null) {
		String theitem = player.getHeldItem().getUnlocalizedName().substring(5);
		if (theitem.equals("unmagneticMagnet")) {
			ItemStack is = player.getHeldItem();
			--is.stackSize;
			is = new ItemStack(Techcraft.normalMagnet,1);
		}
	}
	return true;
}

Please help

-Toastrackenigma

Thanks, that worked 

I was going to use the local is variable as what to set the new item to, I never thought that that would change the item in the player's hand

 

For future reference my final code now is:

public boolean onBlockActivated(World world, int x, int y, int z, EntityPlayer player, int par6, float par7, float par8, float par9) {
	if (player.getHeldItem()!=null) {
		String theitem = player.getHeldItem().getUnlocalizedName().substring(5);
		if (theitem.equals("unmagneticMagnet")) {
			player.setCurrentItemOrArmor(0, new ItemStack(Techcraft.normalMagnet,1));
		}
	}
	return true;
}