Flutter窗口管理插件glfw3的使用
Flutter窗口管理插件glfw3的使用
概述
glfw3 for Dart
是一个用于在Dart中进行窗口管理和OpenGL上下文创建的插件。它依赖于 ffi
包,适用于Windows 64位和Linux系统。
依赖
- ffi ^2.1.2
注意事项
该插件目前支持Windows 64位和Linux系统。
示例代码
以下是一个完整的示例demo,展示了如何使用 glfw3
插件来创建和管理窗口,并处理各种事件回调。
import 'dart:ffi';
import 'package:ffi/ffi.dart';
import 'package:glfw3/glfw3.dart';
// 定义各种回调函数
void windowPosCallback(Pointer<GLFWwindow> window, int xpos, int ypos) {
print('windowPosCallback: xpos=$xpos ypos=$ypos');
}
void windowSizeCallback(Pointer<GLFWwindow> window, int width, int height) {
print('windowSizeCallback: width=$width height=$height');
}
void windowCloseCallback(Pointer<GLFWwindow> window) {
print('windowCloseCallback!');
}
void windowRefreshCallback(Pointer<GLFWwindow> window) {
print('windowRefreshCallback!');
}
void windowFocusCallback(Pointer<GLFWwindow> window, int focused) {
print('windowFocusCallback: focused=$focused');
}
void windowIconifyCallback(Pointer<GLFWwindow> window, int iconified) {
print('windowIconifyCallback: iconified=$iconified');
}
void windowMaximizeCallback(Pointer<GLFWwindow> window, int maximized) {
print('windowMaximizeCallback: maximized=$maximized');
}
void framebufferSizeCallback(Pointer<GLFWwindow> window, int width, int height) {
print('framebufferSizeCallback: width=$width height=$height');
}
void windowContentScaleCallback(Pointer<GLFWwindow> window, double xscale, double yscale) {
print('windowContentScaleCallback: xscale=$xscale yscale=$yscale');
}
void mouseButtonCallback(Pointer<GLFWwindow> window, int button, int action, int mods) {
print('mouseCallback: button=$button action=$action mods=$mods');
}
void cursorPosCallback(Pointer<GLFWwindow> window, double xpos, double ypos) {
print('cursorPosCallback: xpos=$xpos ypos=$ypos');
}
void cursorEnterCallback(Pointer<GLFWwindow> window, int entered) {
print('cursorEnterCallback: entered=$entered');
}
void scrollCallback(Pointer<GLFWwindow> window, double xoffset, double yoffset) {
print('scrollCallback: xoffset=$xoffset yoffset=$yoffset');
}
void keyCallback(Pointer<GLFWwindow> window, int key, int scancode, int action, int mods) {
print('keyCallback: key=$key scancode=$scancode action=$action mods=$mods');
}
void charCallback(Pointer<GLFWwindow> window, int codepoint) {
print('charCallback: codepoint=${String.fromCharCode(codepoint)}');
}
void charModsCallback(Pointer<GLFWwindow> window, int codepoint, int mods) {
print('charModsCallback: codepoint=${String.fromCharCode(codepoint)} mods=$mods');
}
void dropCallback(Pointer<GLFWwindow> window, int pathCount, Pointer<Pointer<Utf8>> paths) {
for (var i = 0; i < pathCount; i++) {
var path = (paths + i).value;
print('dropCallback: path[$i]=${path.toDartString()}');
}
}
// 主函数
int main() {
if (glfwInit() == GLFW_FALSE) {
return -1;
}
// 创建窗口
var window = glfwCreateWindow(640, 480, "Hello GLFW", nullptr, nullptr);
if (window == nullptr) {
glfwTerminate();
return -1;
}
// 设置回调函数
glfwSetWindowPosCallback(window, Pointer.fromFunction(windowPosCallback));
glfwSetWindowSizeCallback(window, Pointer.fromFunction(windowSizeCallback));
glfwSetWindowCloseCallback(window, Pointer.fromFunction(windowCloseCallback));
glfwSetWindowRefreshCallback(window, Pointer.fromFunction(windowRefreshCallback));
glfwSetWindowFocusCallback(window, Pointer.fromFunction(windowFocusCallback));
glfwSetWindowIconifyCallback(window, Pointer.fromFunction(windowIconifyCallback));
glfwSetWindowMaximizeCallback(window, Pointer.fromFunction(windowMaximizeCallback));
glfwSetFramebufferSizeCallback(window, Pointer.fromFunction(framebufferSizeCallback));
glfwSetWindowContentScaleCallback(window, Pointer.fromFunction(windowContentScaleCallback));
glfwSetMouseButtonCallback(window, Pointer.fromFunction(mouseButtonCallback));
glfwSetCursorPosCallback(window, Pointer.fromFunction(cursorPosCallback));
glfwSetScrollCallback(window, Pointer.fromFunction(scrollCallback));
glfwSetKeyCallback(window, Pointer.fromFunction(keyCallback));
glfwSetCharCallback(window, Pointer.fromFunction(charCallback));
glfwSetCharModsCallback(window, Pointer.fromFunction(charModsCallback));
glfwSetDropCallback(window, Pointer.fromFunction(dropCallback));
// 主循环
while (glfwWindowShouldClose(window) == GLFW_FALSE) {
glfwSwapBuffers(window);
glfwWaitEvents();
}
// 清理资源
glfwTerminate();
return 0;
}
更多关于Flutter窗口管理插件glfw3的使用的实战教程也可以访问 https://www.itying.com/category-92-b0.html
更多关于Flutter窗口管理插件glfw3的使用的实战系列教程也可以访问 https://www.itying.com/category-92-b0.html
在Flutter中直接使用GLFW3进行窗口管理并不常见,因为GLFW3是一个专门用于C/C++的库,而Flutter是一个用于构建跨平台UI的框架,主要使用Dart语言。然而,你可以通过一些方法将GLFW3与Flutter结合使用,比如通过平台通道(Platform Channels)调用原生代码。
以下是一个基本的例子,展示如何在Flutter中通过平台通道调用原生代码(在这个例子中,原生代码使用GLFW3来创建一个窗口)。请注意,这个例子假设你已经在Android和iOS平台上设置了原生代码支持。
1. 设置Flutter项目
首先,创建一个新的Flutter项目:
flutter create glfw_flutter_example
cd glfw_flutter_example
2. 添加平台通道支持
在lib
目录下,打开main.dart
文件,并添加平台通道代码:
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
static const platform = MethodChannel('com.example.glfw_flutter_example/glfw');
@override
Widget build(BuildContext context) {
return MaterialApp(
home: Scaffold(
appBar: AppBar(
title: Text('GLFW3 Flutter Example'),
),
body: Center(
child: ElevatedButton(
onPressed: _createWindow,
child: Text('Create GLFW Window'),
),
),
),
);
}
Future<void> _createWindow() async {
try {
final result = await platform.invokeMethod('createWindow');
print('GLFW Window created: $result');
} on PlatformException catch (e) {
print("Failed to create GLFW window: '${e.message}'.");
}
}
}
3. 在Android平台上实现原生代码
在android/app/src/main/java/com/example/glfw_flutter_example/
目录下,创建一个新的Java类,比如GlfwPlugin.java
:
package com.example.glfw_flutter_example;
import android.content.Context;
import androidx.annotation.NonNull;
import io.flutter.embedding.engine.plugins.FlutterPlugin;
import io.flutter.embedding.engine.plugins.activity.ActivityAware;
import io.flutter.embedding.engine.plugins.activity.ActivityPluginBinding;
import io.flutter.plugin.common.MethodCall;
import io.flutter.plugin.common.MethodChannel;
import io.flutter.plugin.common.MethodChannel.MethodCallHandler;
import io.flutter.plugin.common.MethodChannel.Result;
import org.lwjgl.glfw.GLFW;
import org.lwjgl.system.MemoryStack;
import org.lwjgl.system.MemoryUtil;
public class GlfwPlugin implements FlutterPlugin, MethodCallHandler, ActivityAware {
private MethodChannel channel;
private Context applicationContext;
@Override
public void onAttachedToEngine(@NonNull FlutterPluginBinding flutterPluginBinding) {
channel = new MethodChannel(flutterPluginBinding.getBinaryMessenger(), "com.example.glfw_flutter_example/glfw");
channel.setMethodCallHandler(this);
}
@Override
public void onMethodCall(@NonNull MethodCall call, @NonNull Result result) {
if (call.method.equals("createWindow")) {
createWindow();
result.success("Window created");
} else {
result.notImplemented();
}
}
@Override
public void onDetachedFromEngine(@NonNull FlutterPluginBinding binding) {
channel.setMethodCallHandler(null);
}
private void createWindow() {
if (!GLFW.glfwInit()) {
throw new RuntimeException("Failed to initialize GLFW");
}
try (MemoryStack stack = MemoryStack.stackPush()) {
long window = GLFW.glfwCreateWindow(800, 600, "GLFW Window", MemoryUtil.NULL, MemoryUtil.NULL);
if (window == MemoryUtil.NULL) {
throw new RuntimeException("Failed to create GLFW window");
}
GLFW.glfwMakeContextCurrent(window);
GLFW.glfwSwapInterval(1); // Enable vsync
// Here you can add more GLFW window management code
// ...
// For simplicity, we just sleep for a few seconds to keep the window open
try {
Thread.sleep(5000);
} catch (InterruptedException e) {
e.printStackTrace();
}
GLFW.glfwDestroyWindow(window);
}
GLFW.glfwTerminate();
}
@Override
public void onAttachedToActivity(ActivityPluginBinding binding) {
applicationContext = binding.getActivity().getApplicationContext();
}
@Override
public void onDetachedFromActivityForConfigChanges() {
// No-op
}
@Override
public void onReattachedToActivityForConfigChanges(ActivityPluginBinding binding) {
applicationContext = binding.getActivity().getApplicationContext();
}
@Override
public void onDetachedFromActivity() {
// No-op
}
}
注意:上面的Java代码使用了LWJGL的GLFW绑定,而不是直接使用GLFW3的C库。这是因为直接在Android上使用C库需要更多的配置工作,而LWJGL提供了一个方便的Java绑定。你可能需要在build.gradle
文件中添加LWJGL的依赖。
4. 在iOS平台上实现原生代码(可选)
对于iOS平台,你需要使用Objective-C或Swift来编写原生代码,并通过Flutter的平台通道进行通信。这个过程与Android类似,但实现细节会有所不同。由于篇幅限制,这里不提供完整的iOS实现代码。
5. 注册插件
在android/app/src/main/kotlin/com/example/glfw_flutter_example/MainActivity.kt
(如果你使用的是Kotlin)或MainActivity.java
中添加插件注册代码:
package com.example.glfw_flutter_example
import io.flutter.embedding.android.FlutterActivity
class MainActivity: FlutterActivity() {
override fun configureFlutterEngine(flutterEngine: FlutterEngine) {
super.configureFlutterEngine(flutterEngine)
FlutterEngineCache
.getInstance()
.put("my_engine_id", flutterEngine)
GlfwPlugin().registerWith(flutterEngine.dartExecutor.binaryMessenger)
}
}
(对于Java,相应的代码会略有不同)
总结
上面的例子展示了如何在Flutter中通过平台通道调用原生代码来创建GLFW窗口。然而,请注意,直接在移动平台上使用GLFW可能并不是最佳实践,因为GLFW主要是为桌面平台设计的。在移动平台上,你可能更倾向于使用平台特定的窗口和图形API,如Android的SurfaceView和iOS的UIKit/Metal。
此外,由于GLFW和Flutter的运行环境差异较大,直接在Flutter应用中嵌入GLFW窗口可能会遇到一些挑战,比如窗口管理、事件处理等。因此,在实际项目中,你可能需要更深入地了解Flutter和原生平台的交互机制,并进行相应的适配和优化。