Putting nodes in variables

Help Programming
1

Godot Version

4.3

So what I’m trying to do is to basically create a variable that contains nodes and edit them all through this, here’s the script

var scene = 0
var child = [$Panel1,$Panel2]

func _on_buttonscene_pressed() -> void:
	scene += 1
	print (scene)
	
	if scene == 0:
		for panel in child:
			child.visible = false
		
		$Panel2.visible = true
		
	
	elif scene == 1:
		for panel in child:
			child.visible = false
		
		$Panel2.visible = true
2

You have a number of issues in your code:

  1. Whether scene equals 1 or 2, you are always showing panel 2. So all those statements have no effect.
  2. You cannot use a reference like $Panel in a variable assignment at the beginning of a file without using @onready
  3. Using an @onready variable in another @onready variable assignment would be dicey.
  4. The use of child as a variable name is really confusing and should be avoided. Case in point, you are trying to operate on the array instead of the members of the array in your for/each loop.
  5. If you fix all the above issues, this code will only result in the second if statement being executed once.

Here’s how you can restructure your code. I assumed you wanted Panel1 to be visible in the first condition.

var scene = 0
var panels: Array

@onready var panel_1: Panel = $Panel1
@onready var panel_2: Panel = $Panel2

func _ready() -> void:
	panels.append(panel_1)
	panels.append(panel_2)

func _on_buttonscene_pressed() -> void:
	scene += 1
	print (scene)
	
	if scene == 0:
		for panel in panels:
			panel.visible = false
		
		panel_1.visible = true
		
	
	elif scene == 1:
		for panel in panels:
			panel.visible = false
		
		panel_2.visible = true

However, like I said in #5, this code will only work the first time you click the button. Assuming you want the button to toggle between the two:

  1. In the Inspector, turn the button’s toggle_mode to true by checking the box.
  2. Connect the `toggled(toggled_on: bool) signal of the button to your code.
  3. Disconnect the pressed() signal.
  4. Use this code:
@onready var panel_1: Panel = $Panel1
@onready var panel_2: Panel = $Panel2


func _on_button_toggled(toggle_mode: bool) -> void:
	panel_1.visible = toggle_mode
	panel_2.visible = !toggle_mode

If they’re not toggling in the order you want, change the function to this:

func _on_button_toggled(toggle_mode: bool) -> void:
	panel_1.visible = !toggle_mode
	panel_2.visible = toggle_mode

You don’t need all that other stuff.

3

Aren’t you doing exactly that in your code?
This:

func _ready() -> void:
	panels.append(panel_1)
	panels.append(panel_2)

is no different than this:
@onready var panels:Array[Panel] = [panel_1, panel_2]

4

You’re right, thanks. Neither would work. It’d have to be:

var scene = 0
var panels: Array
var panel_1: Panel
var panel_2: Panel

func _ready() -> void:
	panel_1 = $Panel1
	panel_2 = $Panel2	
	panels.append(panel_1)
	panels.append(panel_2)

func _on_buttonscene_pressed() -> void:
	scene += 1
	print (scene)
	
	if scene == 0:
		for panel in panels:
			panel.visible = false
		
		panel_1.visible = true
		
	
	elif scene == 1:
		for panel in panels:
			panel.visible = false
		
		panel_2.visible = true
5

Hello there,
You haven’t really mentioned what help you need regarding you code. I assume you wanted to share your code for improvements.

One improvement I would like to share is to only use the child list to change the visibility of panels and remove the conditional check.

func _on_buttonscene_pressed() -> void:
    scene += 1
    print (scene)

    for panel in child:
        child.visible = false  # Hide all the panels

    child[scene].visible = true; # Show the current panel

Further it can be improved by adding a _ready() function that already hides all the panels except the first one on startup.

func _ready() -> void:
   for panel in child:
      panel.visible = false;  # Hide all the panels at startup

   child[scene].visible = true;  # Show the default panel

func _on_buttonscene_pressed() -> void:
    scene += 1
    print (scene)

    child[scene - 1].visible = false;  # Hide the previous panel
    child[scene].visible = true;  # Show the next panel

Please note that I code in C# and haven’t used gdScript in a long time. Kindly forgive me if I had made any mistake above.

6

(Not trying to badger you but) I don’t understand why the other method wouldn’t work.

@onready var panel_1: Panel = $Panel1
@onready var panel_2: Panel = $Panel2

@onready var panels:Array[Panel] = [panel_1, panel_2]

I use that method often enough that I know it seems to work, however if I am doing something that isn’t recommended, I wonder if you can explain why (or point me to some docs)?
And I apologize to the OP here for this bit of sidetrack.

7

It will work sometimes. But it isn’t guaranteed to work. If your file is large enough, Godot will load it faster by using multiple threads. At that point you will get a race condition and you may end up with panels being constructed by a different thread and faster than panels 1 and 2. In which case it will throw a null exception at some point because panels is an array containing two nulls.

Do not trust any onready variable or variable constructed in _ready() until the ready signal has been emitted by your object. This bites you in the behind most often when you have something in _process or _physics_process that uses one of those variables. They can get called before the node is fully constructed.

If this happens you can create a variable is_ready to track it.

var is_ready = false

func _ready() -> void:
	ready.connect(_on_ready)

func _on_ready() -> void:
	is_ready = true

func _physics_process(delta: float) -> void:
	if not is_ready:
		return
	#regular stuff to execute after we are ready

I could have also used is_ready as an example above - it’s just kind of convoluted for that and in that case not good practice.