Flutter Platform View:在 Flutter 中使用Android、iOS的原生 View
2011 年 12 月 10 日
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作者:ImWiki
链接:https://www.jianshu.com/p/8d74a7318c26
声明:本文已获 ImWiki
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我们在进行Flutter开发的时候,有时候是需要用到原生的View,比如WebView、MapView、第三方广告SDK等,Flutter提供了AndroidView、UiKitView可以实现相关功能。
创建项目
这里以在Flutter显示原生的TextView为案例,展示如何实现,创建项目过程这里不展示,建议使用Android Studio进行开发。
编写平台相关的代码
Android
创建PlatformView类
class AndroidTextView(context: Context) : PlatformView { val contentView: TextView = TextView(context) override fun getView(): View { return contentView } override fun dispose() {} }
创建PlatformViewFactory类
class AndroidTextViewFactory : PlatformViewFactory(StandardMessageCodec.INSTANCE) { override fun create(context: Context, viewId: Int, args: Any?): PlatformView { val androidTextView = AndroidTextView(context) androidTextView.contentView.id = viewId val params = args?.let { args as Map } val text = params?.get("text") as CharSequence? text?.let { androidTextView.contentView.text = it } return androidTextView } }
注册工厂,不同版本的注册方式有所不同,这里是1.12.13版本
class MainActivity : FlutterActivity() { override fun configureFlutterEngine(@NonNull flutterEngine: FlutterEngine) { GeneratedPluginRegistrant.registerWith(flutterEngine) val registry = flutterEngine.platformViewsController.registry registry.registerViewFactory("platform_text_view", AndroidTextViewFactory()) } }
iOS
第一步:在info.plist增加io.flutter.embedded_views_preview=true,至关重要。
第二步:创建 PlatformTextView.swift
import Foundation import Flutter class PlatformTextView: NSObject,FlutterPlatformView { let frame: CGRect; let viewId: Int64; var text:String = "" init(_ frame: CGRect,viewID: Int64,args :Any?) { self.frame = frame self.viewId = viewID if(args is NSDictionary){ let dict = args as! NSDictionary self.text = dict.value(forKey: "text") as! String } } func view() -> UIView { let label = UILabel() label.text = self.text label.textColor = UIColor.red label.frame = self.frame return label } }
第三步:创建PlatformTextViewFactory.swift
import Foundation import Flutter class PlatformTextViewFactory: NSObject,FlutterPlatformViewFactory { func create(withFrame frame: CGRect, viewIdentifier viewId: Int64, arguments args: Any?) -> FlutterPlatformView { return PlatformTextView(frame,viewID: viewId,args: args) } func createArgsCodec() -> FlutterMessageCodec & NSObjectProtocol { return FlutterStandardMessageCodec.sharedInstance() } }
第四步:在 AppDelegate.swift 注册
@UIApplicationMain @objc class AppDelegate: FlutterAppDelegate { override func application( _ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]? ) -> Bool { GeneratedPluginRegistrant.register(with: self) let factory = PlatformTextViewFactory() let registrar = self.registrar(forPlugin: "platform_text_view_plugin") registrar.register(factory, withId: "platform_text_view") return super.application(application, didFinishLaunchingWithOptions: launchOptions) } }
编写Flutter代码
import 'package:flutter/foundation.dart'; import 'package:flutter/material.dart'; import 'package:flutter/services.dart'; void main() => runApp(MyApp()); class MyApp extends StatelessWidget { @override Widget build(BuildContext context) { return MaterialApp( title: 'Flutter Demo', theme: ThemeData( primarySwatch: Colors.blue, ), home: MyHomePage(title: 'Flutter Demo Home Page'), ); } } class MyHomePage extends StatefulWidget { MyHomePage({Key key, this.title}) : super(key: key); final String title; @override _MyHomePageState createState() => _MyHomePageState(); } class _MyHomePageState extends State { Widget getPlatformTextView() { if (defaultTargetPlatform == TargetPlatform.android) { return AndroidView( viewType: "platform_text_view", creationParams: {"text": "Android Text View"}, creationParamsCodec: const StandardMessageCodec()); } else if (defaultTargetPlatform == TargetPlatform.iOS) { return UiKitView( viewType: "platform_text_view", creationParams: {"text": "iOS Label"}, creationParamsCodec: const StandardMessageCodec()); } else { return Text("Not supported"); } } @override Widget build(BuildContext context) { return Scaffold( appBar: AppBar( title: Text(widget.title), ), body:getPlatformTextView(), ); } }
运行
完整代码
https://github.com/taoweiji/FlutterPlatformViewExample
参考
https://60devs.com/how-to-add-native-code-to-flutter-app-using-platform-views-android.html