So I have a machine thingy that tells you what mining level your at. Well I have come across a problem when using my machine I need to click on a block. How do I stop this from happening and make it so you can just click on air.

 

Item Class:

 

public class Cordinate_Check extends Item_TypeNormal
{
public Cordinate_Check(){

this.maxStackSize = 1;
this.setUnlocalizedName(Strings.Cordinate_CheckerName);
    this.setCreativeTab(CreativeTabs.tabMisc);
    Item_Registry.register(this);

}
@Override
public boolean onItemUse(ItemStack par1ItemStack, EntityPlayer par2EntityPlayer, World par3World, int par4, int par5, int par6, int par7, float par8, float par9, float par10)
{

if (par3World.isRemote)
    {
        return true;
        
    }
else
{

if (par5 >= 1 && par5 <= 15 )
{
	Minecraft.getMinecraft().thePlayer.addChatMessage(new ChatComponentText("level == diamondLevel"));
}

if (par5 >= 16 && par5 <= 32)
{

	Minecraft.getMinecraft().thePlayer.addChatMessage(new ChatComponentText("level == ironLevel"));

}

if (par5 >= 33 && par5 <= 52)
{
	Minecraft.getMinecraft().thePlayer.addChatMessage(new ChatComponentText("level == coalLevel"));
}

if (par5 >= 53)
{
	Minecraft.getMinecraft().thePlayer.addChatMessage(new ChatComponentText("level == null"));

}

	return false;
}
}
}

Use onItemRightClick instead, but you will not have any block coordinates to check other than those you can get from the player's position.

Minecraft.getMinecraft().thePlayer

This code will CERTAINLY crash on a server, also you have a player argument supplied in your method (so does onItemRightClick suggested by coolAlias), use that.