Godot 学习笔记(2):信号深入讲解

文章目录

前言
相关链接
环境
信号
- 简单项目搭建
- 默认的信号
- - 先在label里面预制接收函数
  - 添加信号
- 自定义无参数信号
- - 为了做区分，我们在label新增一个函数
- 自定义带参数信号
- - Button代码
  - label代码
  - 连接信号
- 自定义复杂参数信号
- - 自定义GodotObject类
  - Button
  - Label
  - 连接信号
- 信号函数回调
- - Callable
  - - Button
    - Lable
    - 连接信号
    - 参数个数不对的异常问题
    - 解决异常方法
总结

前言

这里我们深入学习一下Godot的信号。对于数据流的控制一直是前端最重要的内容。

环境

visual studio 2022
.net core 8.0
godot.net 4.2.1
window 10

信号

信号就是传输数据的一种方式，信号是单向数据流，信号默认是从下往上传递数据的。即子传父

简单项目搭建

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默认的信号

信号的发出和接收是需要配合的，有点像【发布订阅】模式。信号的发布是带有参数的。这里Button是发布者，Lable是订阅者。

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我这里建议先在订阅者一方先新建函数，再链接信号。因为Godot在gdscript中是可以自动新建代码的，但是在.net 中需要我们手动新建代码。

先在label里面预制接收函数

using Godot;
using System;public partial class Label : Godot.Label
{private int num = 0;// Called when the node enters the scene tree for the first time.public override void _Ready(){this.Text = "修改";}// Called every frame. 'delta' is the elapsed time since the previous frame.public override void _Process(double delta){}/// <summary>/// 接受按钮点击/// </summary>public void RecevieButtonDown(){this.Text = $"{num}";num++;}}

添加信号

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自定义无参数信号

我们在Button的代码里面添加信号

using Godot;
using System;public partial class Button : Godot.Button
{// Called when the node enters the scene tree for the first time./// <summary>/// 添加自定义信号/// </summary>[Signal]public delegate void MyButtonClickEventHandler();public override void _Ready(){//在按钮按下时添加信号发送this.ButtonDown += () => EmitSignal(nameof(MyButtonClick));}// Called every frame. 'delta' is the elapsed time since the previous frame.public override void _Process(double delta){}}

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为了做区分，我们在label新增一个函数

	/// <summary>/// 为了做区分，我们新增一个函数/// </summary>public void RecevieButtonDown2(){GD.Print("我是自定义无参信号");this.Text = $"{num}";num++;}

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自定义带参数信号

这边比较复杂，需要了解C# 的delegate。

C#中委托（delegate）与事件（event）的快速理解

不理解的话那就先凑合着用好了。

Button代码

using Godot;
using System;public partial class Button : Godot.Button
{// Called when the node enters the scene tree for the first time./// <summary>/// 添加自定义信号/// </summary>[Signal]public delegate void MyButtonClickEventHandler();private int num = 0;/// <summary>/// 添加带参数型号/// </summary>[Signal]public delegate void AddNumberEventHandler(int number);public override void _Ready(){//我们给AddNumber添加功能，delegate只能添加或者删除函数，有点类似于触发器。//每次调用的时候，num自动++AddNumber += (item) => num++;//在按钮按下时添加信号发送this.ButtonDown += () =>{EmitSignal(nameof(MyButtonClick));//触发按钮信号EmitSignal(nameof(AddNumber),num);};}// Called every frame. 'delta' is the elapsed time since the previous frame.public override void _Process(double delta){}}

label代码

using Godot;
using System;public partial class Label : Godot.Label
{private int num = 0;// Called when the node enters the scene tree for the first time.public override void _Ready(){this.Text = "修改";}// Called every frame. 'delta' is the elapsed time since the previous frame.public override void _Process(double delta){}/// <summary>/// 接受按钮点击/// </summary>public void RecevieButtonDown(){this.Text = $"{num}";num++;}/// <summary>/// 为了做区分，我们新增一个函数/// </summary>public void RecevieButtonDown2(){GD.Print("我是自定义无参信号");this.Text = $"{num}";num++;}public void AddNumber(int number){this.Text = $"{number}";GD.Print($"我是代参数信号,num:[{number}]");}}

连接信号

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自定义复杂参数信号

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GD0202: The parameter of the delegate signature of the signal is not supported¶

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想要了解更多差异，需要看这个文章。

Godot Engine 4.2 简体中文文档编写脚本 C#/.NET

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自定义GodotObject类

using Godot;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;namespace CSharpSimpleTest.models
{public partial class Student:GodotObject{public string Name = "小王";public int Age = 5;public Student() { }}
}

Button

using CSharpSimpleTest.models;
using Godot;
using System;public partial class Button : Godot.Button
{// Called when the node enters the scene tree for the first time./// <summary>/// 添加自定义信号/// </summary>[Signal]public delegate void MyButtonClickEventHandler();private int num = 0;/// <summary>/// 添加带参数型号/// </summary>[Signal]public delegate void AddNumberEventHandler(int number);private Student student = new Student() { Name = "小王",Age = 24};[Signal]public delegate void StudentEventHandler(Student student);  public override void _Ready(){//我们给AddNumber添加功能，delegate只能添加或者删除函数，有点类似于触发器。//每次调用的时候，num自动++AddNumber += (item) => num++;//在按钮按下时添加信号发送this.ButtonDown += () =>{EmitSignal(nameof(MyButtonClick));//触发按钮信号EmitSignal(nameof(AddNumber),num);//触发Student信号EmitSignal(nameof(Student),student);};}// Called every frame. 'delta' is the elapsed time since the previous frame.public override void _Process(double delta){}}

Label

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using CSharpSimpleTest.models;
using Godot;
using System;public partial class Label : Godot.Label
{private int num = 0;// Called when the node enters the scene tree for the first time.public override void _Ready(){this.Text = "修改";}// Called every frame. 'delta' is the elapsed time since the previous frame.public override void _Process(double delta){}/// <summary>/// 接受按钮点击/// </summary>public void RecevieButtonDown(){this.Text = $"{num}";num++;}/// <summary>/// 为了做区分，我们新增一个函数/// </summary>public void RecevieButtonDown2(){GD.Print("我是自定义无参信号");this.Text = $"{num}";num++;}public void AddNumber(int number){this.Text = $"{number}";GD.Print($"我是代参数信号,num:[{number}]");}/// <summary>/// 自定义复杂参数/// </summary>/// <param name="student"></param>public void ReviceStudent(Student student){this.Text = $"student:Name[{student.Name}],Age[{student.Age}]";}}

连接信号

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至于对于的显示逻辑，是基于C# Variant这个类

C# Variant

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信号函数回调

Callable

[教程]Godot4 GDscript Callable类型和匿名函数(lambda)的使用

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Button

using Godot;
using System;
using System.Diagnostics;public partial class test_node : Node2D
{// Called when the node enters the scene tree for the first time.private Label _lable;private Button _button;private int num = 0;[Signal]public delegate int NumAddEventHandler();public override void _Ready(){_lable = this.GetNode<Label>("Label");_button = this.GetNode<Button>("Button");_lable.Text = "修改";_button.ButtonDown += _button_ButtonDown;NumAdd += () => num;}public void _button_ButtonDown(){_lable.Text = $"按下修改{num}";GD.Print($"按下修改{num}");num++;}// Called every frame. 'delta' is the elapsed time since the previous frame.public override void _Process(double delta){}}

Lable

using CSharpSimpleTest.models;
using Godot;
using System;public partial class Label : Godot.Label
{private int num = 0;// Called when the node enters the scene tree for the first time.public override void _Ready(){this.Text = "修改";}// Called every frame. 'delta' is the elapsed time since the previous frame.public override void _Process(double delta){}/// <summary>/// 接受按钮点击/// </summary>public void RecevieButtonDown(){this.Text = $"{num}";num++;}/// <summary>/// 为了做区分，我们新增一个函数/// </summary>public void RecevieButtonDown2(){GD.Print("我是自定义无参信号");this.Text = $"{num}";num++;}public void AddNumber(int number){this.Text = $"{number}";GD.Print($"我是代参数信号,num:[{number}]");}/// <summary>/// 自定义复杂参数/// </summary>/// <param name="student"></param>public void ReviceStudent(Student student){this.Text = $"student:Name[{student.Name}],Age[{student.Age}]";}public void CallBackTest(Callable callable, Callable callable2){callable.Call();callable2.Call(23);}}

连接信号

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参数个数不对的异常问题

public void CallBackTest(Callable callable, Callable callable2)
{try{callable.Call();//callable2.Call(23);//如果我们参数个数不对，也不会在C#中抛出异常，会在Godot中抛出异常callable2.Call();}catch (Exception e){GD.Print("发送异常");GD.Print(e.ToString());}}