a apt tools provider some annotation to generate dart code ,like router make page jump simple
flutter中无法使用反射做hook,通常使用Aop比较多,基于builder_runner(Dart代码生成文件库)的 source_gen 可实现注解生成代码 类似 java Aop AbstractProcessor
# pubspec.yaml 引入
dependencies:
# flutter 项目下 dependencies 引入 code_gen (使用 source_gen 编写的 aop lib)
code_gen:
git:
url: git://github.com/iloveq/code_gen.git
ref: main
dev_dependencies:
# flutter 项目下 dev_dependencies 引入 builder_runner
build_runner: ^1.10.0
1:创建 app_router_table.dart 工厂模式引用生成的类(实现了模版方法configureRoutes),通过 build_runner 会生成文件 app_router_table.table.dart
import 'package:code_gen/router_gen.dart';
import 'package:flutter/cupertino.dart';
import 'app_router_table.table.dart'; // 生成的文件
@RouterTable()
abstract class AppRouterTable {
factory AppRouterTable() = $AppRouterTable; // 生成的类
Map<String, WidgetBuilder> configureRoutes();
}
Widget _buildMaterialApp() {
return MaterialApp(
debugShowCheckedModeBanner: false,
theme: ThemeData(
platform: TargetPlatform.iOS,
primarySwatch: Colors.blue,
),
routes: AppRouterTable().configureRoutes(),
initialRoute: "/",
);
}
import '../config/app_router_table.table.dart'; // 引入生成文件
// 主页
@RouterPage(isIndex: true)
class HomePage extends StatefulWidget {
HomePage({Key key}) : super(key: key);
@override
_HomePageState createState() => _HomePageState();
}
class _HomePageState extends State<HomePage> {
@override
Widget build(BuildContext context) {
return Center(
child: GestureDetector(
child: Text("home page"),
// 跳转(调用生成方法)
onTap: ()=> context.navigator2TestPage(url: "from home page")
),
);
}
}
...
// testPage
import '../config/app_router_table.table.dart';
@RouterPage() // 标明页面 Page
class TestPage extends StatefulWidget{
@RouterArg(required: true) // 标明参数 Arg
final String url = "";
TestPage({Key key}) : super(key: key);
@override
_TestPageState createState() => _TestPageState();
}
class _TestPageState extends State<TestPage>{
@override
Widget build(BuildContext context) {
return Center(
child: GestureDetector(
child: Text(context.getTestPageArguments().url), // 获取参数
onTap: ()=> context.navigator2MinePage(num:2000),
),
);
}
}
...
export 'app_router_table.table.dart';
import 'app_router_table.dart';
import 'package:flutter/cupertino.dart';
import 'package:flutter_app/pages/test_page.dart';
import 'package:flutter_app/pages/home_page.dart';
import 'package:flutter_app/pages/mine_page.dart';
class $AppRouterTable implements AppRouterTable {
@override
Map<String, WidgetBuilder> configureRoutes() {
return <String, WidgetBuilder>{
'/': (context) => HomePage(),
'TestPage': (context) => TestPage(),
'Mine': (context) => MinePage(),
};
}
}
// **************************************************************************
// TestPage
class TestPageArguments {
final String url;
TestPageArguments({@required this.url});
}
extension TestPageContext on BuildContext {
void navigator2TestPage({@required String url}) {
Navigator.pushNamed(this, "TestPage",
arguments: TestPageArguments(url: url));
}
TestPageArguments getTestPageArguments() {
return ModalRoute.of(this).settings.arguments;
}
}
// **************************************************************************
// **************************************************************************
// MinePage
class MinePageArguments {
final int num;
MinePageArguments({this.num});
}
extension MinePageContext on BuildContext {
void navigator2MinePage({int num}) {
Navigator.pushNamed(this, "Mine", arguments: MinePageArguments(num: num));
}
MinePageArguments getMinePageArguments() {
return ModalRoute.of(this).settings.arguments;
}
}
// **************************************************************************
├── README.md
├── build.yaml
├── lib
│ ├── builder.dart
│ ├── router_gen.dart
│ └── src
│ ├── annotation
│ │ ├── router_arg.dart
│ │ ├── router_page.dart
│ │ └── router_table.dart
│ ├── generator
│ │ ├── router_generator.dart
│ │ └── router_table_generator.dart
│ └── tools
│ └── router_collector.dart
├── pubspec.lock
└── pubspec.yaml
name: code_gen
description: auto generate router params
version: 0.0.1
author: haoran
homepage: [email protected]
environment:
sdk: ">=2.1.0 <3.0.0"
dependencies:
analyzer: any
build: any
build_config: '>=0.3.0'
source_gen: ^0.9.7
dev_dependencies:
build_runner: ^1.10.0
targets:
$default:
builders:
# code_gen 工程下的 router_gen_builder(builder 名字随意,和下面对应就可以)
code_gen|router_gen_builder:
options: { 'write': true }
enabled: true
generate_for:
exclude: ['**.params.g.dart']
code_gen|router_table_gen_builder:
options: { 'write': true }
enabled: true
generate_for:
exclude: ['**.table.dart']
builders:
router_gen_builder:
import: "package:code_gen/builder.dart" # builder.dart 文件位置
builder_factories: ["generateRouterParams"] # 对应 build.dart 文件中的方法
build_extensions: {".dart": ['.params.g.dart']} # 生成文件后缀名
auto_apply: dependents
build_to: source
# runs_before 先于 router_table_gen_builder 执行
runs_before: ['code_gen|router_table_gen_builder']
router_table_gen_builder:
import: "package:code_gen/builder.dart"
builder_factories: ["generateRouterTable"]
build_extensions: {".dart": ['.table.dart']}
auto_apply: dependents
build_to: source
// build.dart
import 'package:build/build.dart';
import 'package:source_gen/source_gen.dart';
import 'src/generator/router_generator.dart';
import 'src/generator/router_table_generator.dart';
Builder generateRouterParams(BuilderOptions options) =>
LibraryBuilder(RouterGenerator(), generatedExtension:'.params.g.dart');
Builder generateRouterTable(BuilderOptions options)=>
LibraryBuilder(RouterTableGenerator(), generatedExtension: '.table.dart');
// 定义注解:
class RouterTable{
const RouterTable();
}
class RouterPage {
final bool isIndex;
final String path;
const RouterPage({this.path = "",this.isIndex = false});
}
class RouterArg {
final bool required;
const RouterArg({this.required = false});
}
// 创建注解生成器:
// 1 RouterGenerator:
class RouterGenerator extends GeneratorForAnnotation<RouterPage> {
static RouterCollector collector = RouterCollector();
@override
generateForAnnotatedElement(
Element element, ConstantReader annotation, BuildStep buildStep) {
print(element);
if (element.kind == ElementKind.CLASS) {
var importStr = "";
if (buildStep.inputId.path.contains('lib/')) {
importStr =
"package:${buildStep.inputId.package}/${buildStep.inputId.path.replaceFirst('lib/', '')}";
} else {
importStr = "${buildStep.inputId.path}";
}
collector.importList.add(importStr);
String className = element.name;
String aptRouterPath = annotation.read("path").stringValue;
String routerName = aptRouterPath != null && aptRouterPath.isNotEmpty
? aptRouterPath
: className;
var page = Page();
page.arguments = [];
for (FieldElement e in ((element as ClassElement).fields)) {
List<ElementAnnotation> fieldAnnotationList = e.metadata;
fieldAnnotationList.forEach((element) {
if (element.toString().startsWith("@RouterArg")) {
Argument argument = Argument();
argument.isRequired = element
.computeConstantValue()
.getField("required")
.toBoolValue();
argument.name = e.name;
print("arguments-field: ${e.toString()}");
String type_ = e.toString().split(" ")[0];
argument.type = type_.replaceAll("*", "");
page.arguments.add(argument);
print("arguments: ${argument.toString()}");
}
});
}
if (aptRouterPath == "/" || annotation.read("isIndex").boolValue) {
page.routerPath = "/";
page.name = className;
collector.indexRouter["/"] = page;
} else {
page.name = className;
page.routerPath = routerName;
collector.routerMap[routerName] = page;
}
}
return null;
}
}
// 2 RouterTableGenerator:
class RouterTableGenerator extends GeneratorForAnnotation<RouterTable> {
@override
generateForAnnotatedElement(
Element element, ConstantReader annotation, BuildStep buildStep) {
if (element.kind == ElementKind.CLASS) {
String path = buildStep.inputId.path; // lib/xxx.dart
String relatedFileName = Path.basename(path); // xxx.dart
String relatedClassName = element.name;
return generateRouterTable(relatedFileName, relatedClassName);
}
return "class TestTable{}";
}
String generateRouterTable(String relatedFileName, String relatedClassName) {
String export = relatedFileName.split(".")[0]
".table."
relatedClassName.split(".")[1];
String imports = "";
String routerMap = "";
var ArgsAndNavigatorExtension = "";
for (String import in RouterGenerator.collector.importList) {
imports = imports "import '" import "';\n";
}
RouterGenerator.collector.routerMap.forEach((key, value) {
routerMap = routerMap "'${key}':( context ) => ${value.name}(),";
ArgsAndNavigatorExtension =
ArgsAndNavigatorExtension _genArgsAndNavigatorExtension(value);
});
return """
export '${export}';
import '${relatedFileName}';
import 'package:flutter/cupertino.dart';
${imports}
class \$${relatedClassName} implements ${relatedClassName}{
@override
Map<String, WidgetBuilder> configureRoutes() {
return <String,WidgetBuilder>{
'/': ( context) => ${RouterGenerator.collector.indexRouter['/'].name}(),
${routerMap}
};
}
}
${ArgsAndNavigatorExtension}
""";
}
}
String _genArgsAndNavigatorExtension(Page page) {
var fields = "";
var argument = "";
var extension = "";
var constructorParams = ""; // this.a,this.b
var functionParams = ""; // String a,String b
var selectedConstructorParams = ""; // a:a, b:b
if (page.arguments != null && page.arguments.isNotEmpty) {
var size = page.arguments.length;
for (int i = 0; i <= size - 1; i ) {
fields = fields
"final "
page.arguments[i].type
" "
page.arguments[i].name
";\n";
constructorParams = constructorParams
(page.arguments[i].isRequired ? "@required " : "")
"this."
page.arguments[i].name
(size == 1 || i == size - 1 ? "" : ",");
functionParams = functionParams
(page.arguments[i].isRequired ? "@required " : "")
page.arguments[i].type
" "
page.arguments[i].name
(size == 1 || i == size - 1 ? "" : ",");
selectedConstructorParams = selectedConstructorParams
page.arguments[i].name
" : "
page.arguments[i].name
(size == 1 || i == size - 1 ? "" : ",");
}
}
var explainName = "${page.name}";
argument = _genArgument(page, fields, constructorParams);
extension =
_genNavigatorExtension(page, functionParams, selectedConstructorParams);
return """
// **************************************************************************
// ${explainName}
$argument
$extension
// **************************************************************************
""";
}
String _genNavigatorExtension(
Page page, String functionParams, String selectedConstructorParams) {
if (page.arguments == null || page.arguments.isEmpty) {
return """
extension ${page.name}Context on BuildContext{
void navigator2${page.name}(){
Navigator.pushNamed(this, "${page.routerPath}");
}
}
""";
} else {
return """
extension ${page.name}Context on BuildContext{
void navigator2${page.name}(
{${functionParams}}){
Navigator.pushNamed(this, "${page.routerPath}",
arguments:${page.name}Arguments(${selectedConstructorParams})
);
}
${page.name}Arguments get${page.name}Arguments(){
return ModalRoute.of(this).settings.arguments;
}
}
""";
}
}
String _genArgument(Page page, String fields, String constructorParams) {
if (page.arguments == null || page.arguments.isEmpty) {
return "";
}
return """
class ${page.name}Arguments{
${fields}
${page.name}Arguments({${constructorParams}});
}
""";
}
tools : 定义一些数据结构 Page/Arg ,存储 router_gen_builder 解析带 @RouterPage 标记带类信息的结果,用于之后执行 router_table_gen_builder 解析 @RouterTable 生成 .table.dart 类
class RouterCollector<T> {
List<String> importList = <String>[];
Map<String, Page> routerMap = <String, Page>{};
Map<String, Page> indexRouter = <String, Page>{};
}
class Page {
String routerPath;
String name;
List<Argument> arguments;
@override
String toString() {
return "{ routerPath:${this.routerPath},name:${this.name},arguments:${this.arguments.toString()}}";
}
}
class Argument {
String name;
String type;
bool isRequired;
@override
String toString() {
return "{ name:${this.name},type:${this.type},isRequired:${this.isRequired}}";
}
}