Objects do not manage memory. If a class inherits from Object, you will have to delete instances of it manually. To do so, call the [method free] method from your script or delete the instance from C++.
Some classes that extend Object add memory management. This is the case of [RefCounted], which counts references and deletes itself automatically when no longer referenced. [Node], another fundamental type, deletes all its children when freed from memory.
Objects export properties, which are mainly useful for storage and editing, but not really so much in programming. Properties are exported in [method _get_property_list] and handled in [method _get] and [method _set]. However, scripting languages and C++ have simpler means to export them.
Objects also receive notifications. Notifications are a simple way to notify the object about different events, so they can all be handled together. See [method _notification].
[b]Note:[/b] Unlike references to a [RefCounted], references to an Object stored in a variable can become invalid without warning. Therefore, it's recommended to use [RefCounted] for data classes instead of [Object].
[b]Note:[/b] The [code]script[/code] property is not exposed like most properties, but it does have a setter and getter ([code]set_script()[/code] and [code]get_script()[/code]).
Each property's [Dictionary] must contain at least [code]name: String[/code] and [code]type: int[/code] (see [enum Variant.Type]) entries. Optionally, it can also include [code]hint: int[/code] (see [enum PropertyHint]), [code]hint_string: String[/code], and [code]usage: int[/code] (see [enum PropertyUsageFlags]).
Called when the object is initialized in memory. Can be defined to take in parameters, that are passed in when constructing.
[b]Note:[/b] If [method _init] is defined with required parameters, then explicit construction is the only valid means of creating an Object of the class. If any other means (such as [method PackedScene.instantiate]) is used, then initialization will fail.
Called whenever the object receives a notification, which is identified in [param what] by a constant. The base [Object] has two constants [constant NOTIFICATION_POSTINITIALIZE] and [constant NOTIFICATION_PREDELETE], but subclasses such as [Node] define a lot more notifications which are also received by this method.
Virtual methods that can be overridden to customize the property revert behavior in the editor.
Returns [code]true[/code] if the property identified by [code]name[/code] can be reverted to a default value. Override [method _property_get_revert] to return the actual value.
Virtual methods that can be overridden to customize the property revert behavior in the editor.
Returns the default value of the property identified by [code]name[/code]. [method _property_can_revert] must be overridden as well for this method to be called.
Virtual method which can be overridden to customize the return value of [method to_string], and thus the object's representation where it is converted to a string, e.g. with [code]print(obj)[/code].
Adds a user-defined [param signal]. Arguments are optional, but can be added as an [Array] of dictionaries, each containing [code]name: String[/code] and [code]type: int[/code] (see [enum Variant.Type]) entries.
Calls the [param method] on the object and returns the result. This method supports a variable number of arguments, so parameters are passed as a comma separated list. Example:
[b]Note:[/b] In C#, the method name must be specified as snake_case if it is defined by a built-in Godot node. This doesn't apply to user-defined methods where you should use the same convention as in the C# source (typically PascalCase).
Calls the [param method] on the object during idle time. This method supports a variable number of arguments, so parameters are passed as a comma separated list. Example:
[b]Note:[/b] In C#, the method name must be specified as snake_case if it is defined by a built-in Godot node. This doesn't apply to user-defined methods where you should use the same convention as in the C# source (typically PascalCase).
Calls the [param method] on the object and returns the result. Contrarily to [method call], this method does not support a variable number of arguments but expects all parameters to be via a single [Array].
A signal can only be connected once to a [Callable]. It will print an error if already connected, unless the signal was connected with [constant CONNECT_REFERENCE_COUNTED]. To avoid this, first, use [method is_connected] to check for existing connections.
If the callable's target is destroyed in the game's lifecycle, the connection will be lost.
[b]Examples with recommended syntax:[/b]
Connecting signals is one of the most common operations in Godot and the API gives many options to do so, which are described further down. The code block below shows the recommended approach for both GDScript and C#.
[codeblocks]
[gdscript]
func _ready():
var button = Button.new()
# `button_down` here is a Signal object, and we thus call the Signal.connect() method,
# not Object.connect(). See discussion below for a more in-depth overview of the API.
button.button_down.connect(_on_button_down)
# This assumes that a `Player` class exists which defines a `hit` signal.
var player = Player.new()
# We use Signal.connect() again, and we also use the Callable.bind() method which
# returns a new Callable with the parameter binds.
print("Hit with weapon %s for %d damage." % [weapon_type, damage])
[/gdscript]
[csharp]
public override void _Ready()
{
var button = new Button();
// C# supports passing signals as events, so we can use this idiomatic construct:
button.ButtonDown += OnButtonDown;
// This assumes that a `Player` class exists which defines a `Hit` signal.
var player = new Player();
// Signals as events (`player.Hit += OnPlayerHit;`) do not support argument binding. You have to use:
player.Hit.Connect(OnPlayerHit, new Godot.Collections.Array {"sword", 100 });
}
private void OnButtonDown()
{
GD.Print("Button down!");
}
private void OnPlayerHit(string weaponType, int damage)
{
GD.Print(String.Format("Hit with weapon {0} for {1} damage.", weaponType, damage));
}
[/csharp]
[/codeblocks]
[b][code]Object.connect()[/code] or [code]Signal.connect()[/code]?[/b]
As seen above, the recommended method to connect signals is not [method Object.connect]. The code block below shows the four options for connecting signals, using either this legacy method or the recommended [method Signal.connect], and using either an implicit [Callable] or a manually defined one.
[codeblocks]
[gdscript]
func _ready():
var button = Button.new()
# Option 1: Object.connect() with an implicit Callable for the defined function.
button.connect("button_down", _on_button_down)
# Option 2: Object.connect() with a constructed Callable using a target object and method name.
While all options have the same outcome ([code]button[/code]'s [signal BaseButton.button_down] signal will be connected to [code]_on_button_down[/code]), option 3 offers the best validation: it will print a compile-time error if either the [code]button_down[/code] signal or the [code]_on_button_down[/code] callable are undefined. On the other hand, option 2 only relies on string names and will only be able to validate either names at runtime: it will print a runtime error if [code]"button_down"[/code] doesn't correspond to a signal, or if [code]"_on_button_down"[/code] is not a registered method in the object [code]self[/code]. The main reason for using options 1, 2, or 4 would be if you actually need to use strings (e.g. to connect signals programmatically based on strings read from a configuration file). Otherwise, option 3 is the recommended (and fastest) method.
For legacy or language-specific reasons, there are also several ways to bind parameters to signals. One can pass a [code]binds[/code] [Array] to [method Object.connect] or [method Signal.connect], or use the recommended [method Callable.bind] method to create a new callable from an existing one, with the given parameter binds.
One can also pass additional parameters when emitting the signal with [method emit_signal]. The examples below show the relationship between those two types of parameters.
[codeblocks]
[gdscript]
func _ready():
# This assumes that a `Player` class exists which defines a `hit` signal.
If you try to disconnect a connection that does not exist, the method will print an error. Use [method is_connected] to ensure that the connection exists.
Emits the given [param signal]. The signal must exist, so it should be a built-in signal of this class or one of its parent classes, or a user-defined signal. This method supports a variable number of arguments, so parameters are passed as a comma separated list. Example:
Deletes the object from memory. Any pre-existing reference to the freed object will become invalid, e.g. [code]is_instance_valid(object)[/code] will return [code]false[/code].
[b]Note:[/b] In C#, the property name must be specified as snake_case if it is defined by a built-in Godot node. This doesn't apply to user-defined properties where you should use the same convention as in the C# source (typically PascalCase).
Returns the object's class as a [String]. See also [method is_class].
[b]Note:[/b] [method get_class] does not take [code]class_name[/code] declarations into account. If the object has a [code]class_name[/code] defined, the base class name will be returned instead.
Gets the object's property indexed by the given [param property_path]. The path should be a [NodePath] relative to the current object and can use the colon character ([code]:[/code]) to access nested properties. Examples: [code]"position:x"[/code] or [code]"material:next_pass:blend_mode"[/code].
[b]Note:[/b] Even though the method takes [NodePath] argument, it doesn't support actual paths to [Node]s in the scene tree, only colon-separated sub-property paths. For the purpose of nodes, use [method Node.get_node_and_resource] instead.
Throws error if the entry does not exist, unless [param default] is not [code]null[/code] (in which case the default value will be returned). See also [method has_meta], [method set_meta] and [method remove_meta].
[b]Note:[/b] Metadata that has a [param name] starting with an underscore ([code]_[/code]) is considered editor-only. Editor-only metadata is not displayed in the Inspector and should not be edited.
Each property's [Dictionary] contain at least [code]name: String[/code] and [code]type: int[/code] (see [enum Variant.Type]) entries. Optionally, it can also include [code]hint: int[/code] (see [enum PropertyHint]), [code]hint_string: String[/code], and [code]usage: int[/code] (see [enum PropertyUsageFlags]).
Returns [code]true[/code] if a metadata entry is found with the given [param name]. See also [method get_meta], [method set_meta] and [method remove_meta].
[b]Note:[/b] Metadata that has a [param name] starting with an underscore ([code]_[/code]) is considered editor-only. Editor-only metadata is not displayed in the Inspector and should not be edited.
[b]Note:[/b] [method is_class] does not take [code]class_name[/code] declarations into account. If the object has a [code]class_name[/code] defined, [method is_class] will return [code]false[/code] for that name.
Send a given notification to the object, which will also trigger a call to the [method _notification] method of all classes that the object inherits from.
If [param reversed] is [code]true[/code], [method _notification] is called first on the object's own class, and then up to its successive parent classes. If [param reversed] is [code]false[/code], [method _notification] is called first on the highest ancestor ([Object] itself), and then down to its successive inheriting classes.
Notify the editor that the property list has changed by emitting the [signal property_list_changed] signal, so that editor plugins can take the new values into account.
[b]Note:[/b] Metadata that has a [param name] starting with an underscore ([code]_[/code]) is considered editor-only. Editor-only metadata is not displayed in the Inspector and should not be edited.
[b]Note:[/b] In C#, the property name must be specified as snake_case if it is defined by a built-in Godot node. This doesn't apply to user-defined properties where you should use the same convention as in the C# source (typically PascalCase).
Assigns a new value to the given property, after the current frame's physics step. This is equivalent to calling [method set] via [method call_deferred], i.e. [code]call_deferred("set", property, value)[/code].
[b]Note:[/b] In C#, the property name must be specified as snake_case if it is defined by a built-in Godot node. This doesn't apply to user-defined properties where you should use the same convention as in the C# source (typically PascalCase).
Assigns a new value to the property identified by the [param property_path]. The path should be a [NodePath] relative to the current object and can use the colon character ([code]:[/code]) to access nested properties. Example:
To remove a given entry from the object's metadata, use [method remove_meta]. Metadata is also removed if its value is set to [code]null[/code]. This means you can also use [code]set_meta("name", null)[/code] to remove metadata for [code]"name"[/code]. See also [method has_meta] and [method get_meta].
[b]Note:[/b] Metadata that has a [param name] starting with an underscore ([code]_[/code]) is considered editor-only. Editor-only metadata is not displayed in the Inspector and should not be edited.
If the object already had a script, the previous script instance will be freed and its variables and state will be lost. The new script's [method _init] method will be called.
Translates a message using translation catalogs configured in the Project Settings. An additional context could be used to specify the translation context.
Only works if message translation is enabled (which it is by default), otherwise it returns the [param message] unchanged. See [method set_message_translation].
Translates a message involving plurals using translation catalogs configured in the Project Settings. An additional context could be used to specify the translation context.
Only works if message translation is enabled (which it is by default), otherwise it returns the [param message] or [param plural_message] unchanged. See [method set_message_translation].
The number [param n] is the number or quantity of the plural object. It will be used to guide the translation system to fetch the correct plural form for the selected language.
[b]Note:[/b] Negative and floating-point values usually represent physical entities for which singular and plural don't clearly apply. In such cases, use [method tr].
Connect a signal as reference-counted. This means that a given signal can be connected several times to the same target, and will only be fully disconnected once no references are left.
