[Flutter]Tạo Widget với Android Native bằng Platform Views

by doanquyet
52 views

Một ví dụ về tạo 2 widget được triển khai dưới Android Native

Dưới Native

Đầu tiên, chúng ta sẽ tạo 2 class FirstWidget.kt và SecondWidget.kt:

  • FirstWidget.kt : Sử dụng file .xml
import android.content.Context
import android.view.LayoutInflater
import android.view.View
import io.flutter.plugin.platform.PlatformView

internal class FirstWidget(context: Context, id: Int, creationParams: Map<String?, Any?>?) : PlatformView {
    private val view: View

    override fun getView(): View {
        return view
    }

    init {
        view = LayoutInflater.from(context).inflate(R.layout.first_widget, null)
    }

    override fun dispose() {
    }
}
  • first_widget.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    tools:context=".MainActivity"
    tools:showIn="@layout/first_widget">

    <TextView
        android:id="@+id/first_widget_text"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="FirstWidget from Android!"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>
  • SecondWidget.kt: 1 cách khác để tạo view
import android.content.Context
import android.graphics.Color
import android.view.View
import android.widget.TextView
import io.flutter.plugin.platform.PlatformView

internal class SecondWidget(context: Context, id: Int, creationParams: Map<String?, Any?>?) : PlatformView {
    private val textView = TextView(context)

    override fun getView(): View {
        return textView
    }

    override fun dispose() {}

    init {
        textView.textSize = 20f
        textView.setBackgroundColor(Color.rgb(255, 255, 255))
        textView.text = "Rendered on a native Android view (id: $id)"
    }
}

Tạo 2 class FirstWidgetFactory.kt và SecondWidgetFactory.kt:

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

class FirstWidgetFactory : PlatformViewFactory(StandardMessageCodec.INSTANCE) {
    override fun create(context: Context, viewId: Int, args: Any?): PlatformView {
        val creationParams = args as Map<String?, Any?>?
        return FirstWidget(context, viewId, creationParams)
    }
}
  • SecondWidgetFactory.kt
import android.content.Context
import io.flutter.plugin.common.StandardMessageCodec
import io.flutter.plugin.platform.PlatformView
import io.flutter.plugin.platform.PlatformViewFactory

class SecondWidgetFactory : PlatformViewFactory(StandardMessageCodec.INSTANCE) {
    override fun create(context: Context, viewId: Int, args: Any?): PlatformView {
        val creationParams = args as Map<String?, Any?>?
        return SecondWidget(context, viewId, creationParams)
    }
}

Tại MainActivity.kt:

import io.flutter.embedding.android.FlutterActivity
import io.flutter.embedding.engine.FlutterEngine
import io.flutter.plugins.GeneratedPluginRegistrant

class MainActivity : FlutterActivity() {

    override fun configureFlutterEngine(flutterEngine: FlutterEngine) {
        GeneratedPluginRegistrant.registerWith(flutterEngine)
        flutterEngine
                .platformViewsController
                .registry
                .registerViewFactory("com.example.flutter_app_demo1.FirstWidgetPlugin", FirstWidgetFactory())
        flutterEngine
                .platformViewsController
                .registry
                .registerViewFactory("com.example.flutter_app_demo1.SecondWidgetPlugin", SecondWidgetFactory())
    }

}

Về phần Dart

Tạo 2 file first_widget.dart và second_widget.dart:

  • first_widget.dart
import 'package:flutter/foundation.dart';
import 'package:flutter/gestures.dart';
import 'package:flutter/material.dart';
import 'package:flutter/rendering.dart';
import 'package:flutter/services.dart';


class FirstWidget extends StatefulWidget {
  const FirstWidget({
    Key? key,
  }) : super(key: key);


  @override
  State<StatefulWidget> createState() => _FirstWidgetState();
}

class _FirstWidgetState extends State<FirstWidget> {
   String viewType = 'com.example.flutter_app_demo1.FirstWidgetPlugin';
   Map<String, dynamic> creationParams = <String, dynamic>{};
  @override
  Widget build(BuildContext context) {
    if (defaultTargetPlatform == TargetPlatform.android) {
      return SizedBox(
        width: 200,
        child: PlatformViewLink(
          viewType: viewType,
          surfaceFactory:
              (BuildContext context, PlatformViewController controller) {
            return AndroidViewSurface(
              controller: controller as AndroidViewController,
              gestureRecognizers:  const <Factory<OneSequenceGestureRecognizer>>{},
              hitTestBehavior: PlatformViewHitTestBehavior.opaque,
            );
          },
          onCreatePlatformView: (PlatformViewCreationParams params) {
            return PlatformViewsService.initSurfaceAndroidView(
              id: params.id,
              viewType: viewType,
              layoutDirection: TextDirection.ltr,
              creationParams: creationParams,
              creationParamsCodec: const StandardMessageCodec(),
              onFocus: () {
                params.onFocusChanged(true);
              },
            )
              ..addOnPlatformViewCreatedListener(params.onPlatformViewCreated)
              ..create();
          },
        ),
      );
    }
    return const Text('iOS platform version is not implemented yet.');
  }

}
  • second_widget.dart
import 'package:flutter/foundation.dart';
import 'package:flutter/gestures.dart';
import 'package:flutter/material.dart';
import 'package:flutter/rendering.dart';
import 'package:flutter/services.dart';

class SecondWidget extends StatefulWidget {
  const SecondWidget({
    Key? key,
  }) : super(key: key);

  @override
  State<StatefulWidget> createState() => _SecondWidgetState();
}

class _SecondWidgetState extends State<SecondWidget> {
  String viewType = "com.example.flutter_app_demo1.SecondWidgetPlugin";
  Map<String, dynamic> creationParams = <String, dynamic>{};
  @override
  Widget build(BuildContext context) {
    if (defaultTargetPlatform == TargetPlatform.android) {
      return PlatformViewLink(
        viewType: viewType,
        surfaceFactory:
            (BuildContext context, PlatformViewController controller) {
          return AndroidViewSurface(
            controller: controller as AndroidViewController,
            gestureRecognizers:  const <Factory<OneSequenceGestureRecognizer>>{},
            hitTestBehavior: PlatformViewHitTestBehavior.opaque,
          );
        },
        onCreatePlatformView: (PlatformViewCreationParams params) {
          return PlatformViewsService.initSurfaceAndroidView(
            id: params.id,
            viewType: viewType,
            layoutDirection: TextDirection.ltr,
            creationParams: creationParams,
            creationParamsCodec: const StandardMessageCodec(),
            onFocus: () {
              params.onFocusChanged(true);
            },
          )
            ..addOnPlatformViewCreatedListener(params.onPlatformViewCreated)
            ..create();
        },
      );
    }
    return const Text('iOS platform version is not implemented yet.');
  }

}

Sau đó gọi lại 2 Widget vừa rồi tại main.dart

@override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Flutter PlatformView Example'),
      ),
      body: Column(
        mainAxisSize: MainAxisSize.min,
        mainAxisAlignment: MainAxisAlignment.spaceAround,
        children: const <Widget>[
          Card(
            child: SizedBox(
              height: 200,
              child: FirstWidget(),
            ),
          ),
          Card(
            child: SizedBox(
              height: 200,
              child: SecondWidget(),
            ),
          ),
        ],
      ),
    );
  }

PlatformView

PlatformView là một tính năng Flutter cần thực hiện để hiển thị Native-UIs toàn diện trên Android View / UIKitView.

Nếu bạn muốn biết thêm thông tin về PlatformView, hãy xem tài liệu chính thức:

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