使用 Platform Views 在 Flutter 应用中托管原生 Android 和 iOS 视图

Question

我正在尝试遵循 Flutter 教程：https://flutter.dev/docs/development/platform-integration/platform-views，但 Java 代码有错误并且无法编译。具体来说，NativeViewFactory 被定义为有两个参数，但随后调用时不带参数。可以对代码进行哪些更改，以便在 Flutter 中编译和显示原生 Android 视图？

在 NativeViewFactory.java 中：

 @NonNull private final BinaryMessenger messenger;
 @NonNull private final View containerView;

 NativeViewFactory(@NonNull BinaryMessenger messenger, @NonNull View containerView) {
    super(StandardMessageCodec.INSTANCE);
    this.messenger = messenger;
    this.containerView = containerView;
  }

在 MainActivity.java 中：

public void configureFlutterEngine(@NonNull FlutterEngine flutterEngine) {
        flutterEngine
            .getPlatformViewsController()
            .getRegistry()
            .registerViewFactory("<platform-view-type>", new NativeViewFactory());
    }

Answer 1

这是在 Flutter 中显示原生 Android Textview 的工作代码。

Main.dart

import 'package:flutter/material.dart';


void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) => MaterialApp( home: Native() );
}

class Native extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(),
      body: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: <Widget>[
          Expanded( child: AndroidView(viewType: "view1",) ),
        ],
      ),
    );
  }
}

MainActivity.java

package com.example.native_view_test;

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

public class MainActivity extends FlutterActivity {
    @Override
    public void configureFlutterEngine(@NonNull FlutterEngine flutterEngine) {
        super.configureFlutterEngine(flutterEngine);
        flutterEngine
                .getPlatformViewsController()
                .getRegistry()
                .registerViewFactory("view1", new NativeViewFactory());
    }
}

NativeViewFactory.java

package com.example.native_view_test;

import android.content.Context;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import java.util.Map;
import io.flutter.plugin.common.StandardMessageCodec;
import io.flutter.plugin.platform.PlatformView;
import io.flutter.plugin.platform.PlatformViewFactory;

class NativeViewFactory extends PlatformViewFactory {

    NativeViewFactory() {
        super(StandardMessageCodec.INSTANCE);
    }

    @Override
    public PlatformView create(@NonNull Context context, int id, @Nullable Object args) {
        final Map<String, Object> creationParams = (Map<String, Object>) args;
        return new NativeView(context, id, creationParams);
    }
}

NativeView.java

package com.example.native_view_test;

import android.content.Context;
import android.graphics.Color;
import android.view.View;
import android.widget.TextView;
import java.util.Map;
import io.flutter.plugin.platform.PlatformView;

class NativeView implements PlatformView {
    private final TextView textView;

    NativeView(Context context, int id, Map<String, Object> creationParams) {
        textView = new TextView(context);
        textView.setTextSize(42);
        textView.setBackgroundColor(Color.rgb(255, 255, 255));
        textView.setText("Rendered on a native Android view (id: " + id + ")");
    }

    @Override
    public View getView() {
        return textView;
    }

    @Override
    public void dispose() {}
}