Flutter学习-项目创建
谢典
Flutter 部分
创建Flutter Module
- 使用Android Studio 直接创建
生成 aar 和 framework
- 编译脚本如下
version=1.2
flutter build aar --build-number=$version
flutter build ios-framework
Flutter中 代码
- main.dart
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:flutter_a/second.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: MyHomePage(title: 'Flutter Demo Home Page'),
//定义 flutter中的路由
routes: {"flutter_a/second": (context) => SecondPage()},
);
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);
final String title;
@override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
int _counter = 0;
String _back = "";
//创建 showToast的Method Channel 进行和Android端通信
MethodChannel methodChannel = MethodChannel("com.flutter_a.showToast");
@override
void initState() {
super.initState();
//监听 Android发送的信息
methodChannel.setMethodCallHandler((call) => _setBack(call));
}
void _incrementCounter() {
setState(() {
_counter++;
});
}
Future<dynamic> _setBack(MethodCall call) {
print("${call.method}::${call.arguments}");
setState(() {
_back = call.arguments;
});
return Future.delayed(Duration(seconds: 1));
}
void _sendToNative(
String msg,
) {
methodChannel.invokeMethod("showToast", {"msg": msg});
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Text(_back),
Text(
'You have pushed the button this many times:',
),
Text(
'$_counter',
style: Theme.of(context).textTheme.headline4,
),
IconButton(
icon: Icon(Icons.send),
onPressed: () {
_sendToNative("msg:$_counter");
}),
MaterialButton(
onPressed: () {
Navigator.of(context)
.push(MaterialPageRoute(builder: (context) {
return SecondPage();
}));
},
child: Center(
child: Row(
children: [Text("next"), Icon(Icons.skip_next)],
),
),
)
],
),
),
floatingActionButton: FloatingActionButton(
onPressed: _incrementCounter,
tooltip: 'Increment',
child: Icon(Icons.add),
),
);
}
}
- second.dart
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
class SecondPage extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text("second"),
),
body: Center(
child: Text("second page"),
),
);
}
}
Android 部分
在 Android 中引入 生成的aar
- 在app/build.gradle中 加入
repositories {
String storageUrl = System.env.FLUTTER_STORAGE_BASE_URL ?: "https://storage.googleapis.com"
maven {
url '换成自己的Flutter module的路径/flutter_modules/flutter_a/build/host/outputs/repo'
}
maven {
url "$storageUrl/download.flutter.io"
}
}
dependencies{
....
debugImplementation 'com.example.flutter_a:flutter_debug:1.0'
releaseImplementation 'com.example.flutter_a:flutter_release:1.0'
}
使用 FlutterEngineCache 缩减 启动Flutter 界面的黑屏时间
- 在自定义的Application中 创建FlutterEngine
package com.example.fluttertest2
import android.app.Application
import io.flutter.embedding.engine.FlutterEngine
import io.flutter.embedding.engine.FlutterEngineCache
import io.flutter.embedding.engine.dart.DartExecutor
class MyApplication : Application() {
companion object {
const val CACHE_MAIN = "main"
const val CACHE_SECOND = "second"
const val CACHE_ID = "CACHE_ID"
}
override fun onCreate() {
super.onCreate()
val flutterEngine = FlutterEngine(this)
flutterEngine.dartExecutor.executeDartEntrypoint(DartExecutor.DartEntrypoint.createDefault())
FlutterEngineCache.getInstance().put(CACHE_MAIN, flutterEngine)
val second = FlutterEngine(this)
// 设置 Flutter的初始化路由，不设置则使用 默认的路由
second.navigationChannel.setInitialRoute("flutter_a/second")
second.dartExecutor.executeDartEntrypoint(DartExecutor.DartEntrypoint.createDefault())
FlutterEngineCache.getInstance().put(CACHE_SECOND, second)
}
}
flutter_a/second 是在 main.dart 中“routes”定义的
- 在 自定义的FlutterActivity中获取缓存的FlutterEngine
package com.example.fluttertest2
import com.example.fluttertest2.MyApplication.Companion.CACHE_SECOND
import io.flutter.embedding.android.FlutterActivity
import io.flutter.embedding.engine.FlutterEngine
import io.flutter.plugins.GeneratedPluginRegistrant
class SecondFlutterActivity : FlutterActivity() {
override fun configureFlutterEngine(flutterEngine: FlutterEngine) {
super.configureFlutterEngine(flutterEngine)
GeneratedPluginRegistrant.registerWith(flutterEngine)
}
override fun getCachedEngineId(): String? {
//FlutterEngineCache 中 FlutterEngine的key
return CACHE_SECOND
}
}
- Android原生Activity跳转到flutter界面的方式
package com.example.fluttertest2
import android.content.Intent
import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import com.example.fluttertest2.MyApplication.Companion.CACHE_ID
import com.example.fluttertest2.MyApplication.Companion.CACHE_MAIN
import com.example.fluttertest2.MyApplication.Companion.CACHE_SECOND
import kotlinx.android.synthetic.main.activity_main.*
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
goFlutter.setOnClickListener {
//将 FlutterEngineCache 中 FlutterEngine的 key 传递到 FlutterActivity，根据key加载不同的FlutterEngine的
startActivity(Intent(this, MyFlutterActivity::class.java).putExtra(CACHE_ID,CACHE_MAIN))
}
goSecond.setOnClickListener {
//打开新的FlutterActivity
startActivity(Intent(this, SecondFlutterActivity::class.java))
//使用一个FlutterActivity
// startActivity(Intent(this, MyFlutterActivity::class.java).putExtra(CACHE_ID,CACHE_SECOND))
}
}
}
- MyFlutterActivity
import com.example.fluttertest2.MyApplication.Companion.CACHE_ID
import io.flutter.embedding.android.FlutterActivity
import io.flutter.embedding.engine.FlutterEngine
import io.flutter.plugins.GeneratedPluginRegistrant
class MyFlutterActivity : FlutterActivity() {
override fun configureFlutterEngine(flutterEngine: FlutterEngine) {
super.configureFlutterEngine(flutterEngine)
GeneratedPluginRegistrant.registerWith(flutterEngine)
}
override fun getCachedEngineId(): String? {
// return CACHE_MAIN
return intent.getStringExtra(CACHE_ID)
}
}
MethodChannel 通信
- Android端在configureFlutterEngine 方法中创建MethodChannel对象：
import android.widget.Toast
import com.example.fluttertest2.MyApplication.Companion.CACHE_ID
import io.flutter.embedding.android.FlutterActivity
import io.flutter.embedding.engine.FlutterEngine
import io.flutter.plugin.common.MethodChannel
import io.flutter.plugins.GeneratedPluginRegistrant
class MyFlutterActivity : FlutterActivity() {
override fun configureFlutterEngine(flutterEngine: FlutterEngine) {
super.configureFlutterEngine(flutterEngine)
GeneratedPluginRegistrant.registerWith(flutterEngine)
val methodChannel = MethodChannel(flutterEngine.dartExecutor.binaryMessenger, "com.flutter_a.showToast")
//监听 flutter发送的信息
methodChannel.setMethodCallHandler { call, result ->
result.success("back from native")
Toast.makeText(
this@MyFlutterActivity,
"from Flutter:${call.argument<String>("msg")}",
Toast.LENGTH_SHORT
).show()
}
//调用 Flutter 中的方法
methodChannel.invokeMethod("sayHi", "hello Flutter", object : MethodChannel.Result {
override fun notImplemented() {}
override fun error(errorCode: String?, errorMessage: String?, errorDetails: Any?) {}
override fun success(result: Any?) {}
})
}
override fun getCachedEngineId(): String? {
// return CACHE_MAIN
return intent.getStringExtra(CACHE_ID)
}
}
IOS部分
- 正在学习中。。。
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