I have an "Quickdraw" enchantment that works by setting the bow item in use immediately on right click, so it doesn't have to draw back all the way to be used. The basic code in 1.8 was:

 

 

 

EntityPlayer player = (EntityPlayer) entity;
ItemStack heldItem = player.getHeldItem();
if (heldItem != null && heldItem.getItem() instanceof ItemBow && this.getEnchantmentLevel(heldItem) > 0) {
   player.setItemInUse(heldItem, heldItem.getMaxItemUseDuration() / 3);
   ((ArrowNockEvent) baseEvent).result = heldItem;
   baseEvent.setCanceled(true);
}

 

 

However the setItemInUse method seems to be gone in 1.9, and I can't find a suitable replacement. What can I do?

The "item in use" mechanic is now activated in EntityLivingBase#setActiveHand. It sets some protected fields, you'd have to write to them using reflection.

 

 

Alright, I did this and the arrow does fire as if the bow was drawn back 100%. Unfortunately the bow still goes through the entire draw-back animation. My code now:

 

 

EntityPlayer player = (EntityPlayer) entity;
ItemStack heldItem = player.getHeldItemMainhand();
if (heldItem != null && heldItem.getItem() instanceof ItemBow && this.getEnchantmentLevel(heldItem) > 0) {
//player.setItemInUse(heldItem, heldItem.getMaxItemUseDuration() / 3);
ReflectionHelper.setPrivateValue(EntityLivingBase.class, player, heldItem, "activeItemStack", "field_184627_bm");
ReflectionHelper.setPrivateValue(EntityLivingBase.class, player, heldItem.getMaxItemUseDuration() / 3, "activeItemStackUseCount", "field_184628_bn");
player.getDataManager().set(ReflectionHelper.getPrivateValue(EntityLivingBase.class, player, "HAND_STATES", "field_184621_as"), (byte) 1);
((ArrowNockEvent) baseEvent).setAction(new ActionResult<>(EnumActionResult.SUCCESS, heldItem));
}

That is because the client simply get's told "using item now" via the HAND_STATES data watcher. The client then uses the getMaxItemUseDuration again.

 

 

So how can I circumvent this? Do I just not set the HAND_STATES?

Would changing the item's maxUseDuration alter the behavior?  You could set it very low and the client would animate through the charge quickly.  You'd still have to wait the full duration to get full power, but it would charge much more quickly, which would probably be more elegant than your prior method.