All of you faced this problem. And now me, too. I wrote some code to catch Keyboard events. like:

 

@SideOnly(Side.CLIENT)
@SubscribeEvent(priority = EventPriority.NORMAL, receiveCanceled = true)
public void onEvent(InputEvent.KeyInputEvent event) {
    if (itemIsHoldinHand.equals(ItemHoldInHand.NONE)) {
        //Do nothing if it is not hold
        return;
    }

    String keyBindingDescKey = "key.attack";
    // make local copy of key binding array
    KeyBinding[] keyBindings = Minecraft.getMinecraft().gameSettings.keyBindings;
    for (KeyBinding binding : keyBindings) {
        if (keyBindingDescKey.equals(binding.getDescriptionKey()) && /*IMPORTANT to do this on second check because its counter based and will reset other key actions when it hits*/ binding.isPressed()) { 
            return;
        }
    }
}

 

This code works well as the attack key is bound to a keyboard key like: R, A, ...

 

But at default the attack key is bound to 

 

KeyCode: -100 (Left mouse button)

 

But thats not the main problem, I knew that there is another event for catching mousecation like:

 

@SideOnly(Side.CLIENT)
@SubscribeEvent(priority = EventPriority.NORMAL, receiveCanceled = true)
public void onEvent(InputEvent.MouseInputEvent event) {
    if (itemIsHoldinHand.equals(ItemHoldInHand.NONE)) {
        //Do nothing if it is not hold
        return;
    }

    ...

    String keyBindingDescKey = "key.attack"; 
    // make local copy of key binding array  
    KeyBinding[] keyBindings = Minecraft.getMinecraft().gameSettings.keyBindings;  
    for (KeyBinding binding : keyBindings) {
       if (keyBindingDescKey.equals(binding.getDescriptionKey()) && /*This same pattern never hits....*/ binding.isPressed())
       { 
          return;  
       } 
    }
}

 

But doing the same thing as before results in nothing. 

Even trying to do:
 

@SideOnly(Side.CLIENT)
@SubscribeEvent(priority = EventPriority.NORMAL, receiveCanceled = true)
public void onEvent(InputEvent.MouseInputEvent event) {
    if (itemIsHoldinHand.equals(ItemHoldInHand.NONE)) {
        //Do nothing if it is not hold
        return;
    }
    boolean isPressed = Minecraft.getMinecraft().gameSettings.keyBindAttack.isPressed();
    if(isPressed){
        System.out.println("Hell yeah");
    }
}

 

Is getting me no result. So I am asking you guys . Is there any pattern, how to or possibility to access the left mouse click (user friendly)

PS: I did add it to the EVENT_BUS
 

    MinecraftForge.EVENT_BUS.register(ModItems.ItemGun);

 

keyBindAttack doesn't work because the left click is already processed as attack. The game resets the pressed flag to false after the process, so you can't detect it when it's bound to attack.

So do you want to detect attacking? If what you need is checking whether left click button is clicked or not, you can use KeyBinding::isKeyDown().

@Abastro So instead of using isPressed on the attack keybinding, isKeyDown() will work?

7 minutes ago, NoFuchsGavin said:

@Abastro So instead of using isPressed on the attack keybinding, isKeyDown() will work?

Yes. One drawback is that it can be detected continuously. I think you should take care of it manually.

@Abastro I think this will not work as I expect. I thought it's possible to override the attack that I can use an item like I wanna to. Pistol -> shoot.

 

So I need to override the default logic for the attack:

 Do not hit the block infront of the player
 Do no animation for hitting 
....

2 minutes ago, NoFuchsGavin said:

@Abastro I think this will not work as I expect. I thought it's possible to override the attack that I can use an item like I wanna to. Pistol -> shoot.

There's easier way for that: subscribe event: PlayerInteractEvent.LeftClickEmpty. Do what you want there.

When you want to block hitting an entity, you can just override Item::onLeftClickEntity.

Spoiler

There's easier way for that: subscribe event: PlayerInteractEvent.LeftClickEmpty. Do what you want there.

What is about remapping keys for attack. Attack on "H" so this will not be on the LeftClick anymore.

12 minutes ago, NoFuchsGavin said:

What is about remapping keys for attack. Attack on "H" so this will not be on the LeftClick anymore.

Actually the name of the event is somewhat misleading. It is always called when attack key/mouse is pressed.

Same for Item::onLeftClickEntity.