Flutter~PlatformView的简单使用

PlatformView 就是AndroidView和UIKitView的总称，允许原生端的view嵌入到flutter项目 中的 Widget。

接下来简单的演示下它的基本使用规则。

1、新建一个Flutter项目，然后在main.dart中：

import 'package:flutter/material.dart';
import 'dart:io';
import 'package:flutter/services.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: const MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({super.key, required this.title});
  final String title;

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Platform.isIOS
          ? const UiKitView(
              viewType: "platform_text_view",
              creationParams: <String, dynamic>{"text": "iOS Label"},
              creationParamsCodec: StandardMessageCodec(),
            )
          : const AndroidView(
              viewType: "platform_text_view",
              creationParams: <String, dynamic>{"text": "Android Text View"},
              creationParamsCodec: StandardMessageCodec(),
            ),
    );
  }
}

其中，iOS对应的是UiKitView ，传递的参数是iOS Label，唯一标识符是：platform_text_view 。android对应的是AndroidView ，传递的参数是Android Text View，唯一标识符是platform_text_view 。

iOS一侧：

新建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
    }
}

新建PlatformTextView.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()
    }
}

修改 AppDelegate.swift

import UIKit
import Flutter

@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)
  }
}

然后在info.plist中添加：

<key>io.flutter.embedded_views_preview</key>

Android一侧：

新建AndroidTextView.kt

package com.example.platformview
import android.content.Context
import android.graphics.Color
import android.view.View
import android.widget.TextView
import io.flutter.plugin.platform.PlatformView

class AndroidTextView(context: Context) : PlatformView {
    val contentView: TextView = TextView(context)
    override fun getView(): View {
        return contentView
    }
    override fun dispose() {}
}

新建AndroidTextViewFactory.kt

package com.example.platformview

import android.content.Context
import io.flutter.plugin.common.StandardMessageCodec
import io.flutter.plugin.platform.PlatformView
import io.flutter.plugin.platform.PlatformViewFactory

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
    }
}

修改MainActivity.kt:

package com.example.platformview

import androidx.annotation.NonNull
import io.flutter.embedding.android.FlutterActivity
import io.flutter.embedding.engine.FlutterEngine
import io.flutter.plugins.GeneratedPluginRegistrant

class MainActivity: FlutterActivity() {
    override fun configureFlutterEngine(@NonNull flutterEngine: FlutterEngine) {
        GeneratedPluginRegistrant.registerWith(flutterEngine)
        val registry = flutterEngine.platformViewsController.registry
        registry.registerViewFactory("platform_text_view", AndroidTextViewFactory())
    }
}

OK，回到flutter工程中，重新运行即可。

本文源码

其他：

Android原生工程中添加Flutter模块

iOS原生工程中添加Flutter模块