flutter学习之嵌入原生View – android

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• 本文主要介绍如何在 flutter中加载原生android的view，之前咱们介绍了flutter加载iOS view。原理也是相似。

1. 创立android中按钮开关符号vi按钮拼音ew

咱们是iOS开发，这里简略介绍下如何加载jvm面试题原生android的view，其流程和咱们iOS view相似。

咱们在android项目的创立一个测试view

package com.example.flutter_android_view
import android.content.Context
import android.view.View
import android.widget.TextView
import io.flutter.plugin.common.BinaryMessenger
import io.flutter.plugin.platform.PlatformView
class TestView(context: Context, messenger: BinaryMessenger, viewId: Int, args: Map<String, Any>?) :
    PlatformView {
    private val textView: TextView = TextView(context)
    init {
        textView.text = "这是一个Android View"
    }
    override fun getView(): View {
        return textView
    }
    override fun dispose() {
        TODO("Not yet implemented")
    }
}

咱们继续创立TestViewFactory

import android.content.Context
import io.flutter.plugin.common.BinaryMessenger
import io.flutter.plugin.common.StandardMessageCodec
import io.flutter.plugin.platform.PlatformView
import io.flutter.plugin.platform.PlatformViewFactory
class TestViewFactory(private val messenger: BinaryMessenger) : PlatformViewFactory(StandardMessageCodec.INSTANCE) {
    override fun create(context: Context, viewId: Int, args: Any?): PlatformView {
        return TestView(context, messenger, viewId, args as Map<String, Any>?)
    }
}

创立TestPlugin

import io.flutter.embedding.engine.plugins.FlutterPlugin
import io.flutter.plugin.common.BinaryMessenger
import io.flutter.plugin.common.PluginRegistry
class TestViewPlugin : FlutterPlugin {
    override fun onAttachedToEngine(binding: FlutterPlugin.FlutterPluginBinding) {
        val messenger: BinaryMessenger = binding.binaryMessenger
        binding
            .platformViewRegistry
            .registerViewFactory(
                "plugins.flutter.io/custom_platform_view", TestViewFactory(messenger))
    }
    companion object {
        @JvmStatic
        fun registerWith(registrar: PluginRegistry.Registrar) {
            registrar
                .platformViewRegistry()
                .registerViewFactory(
                    "plugins.flutter.io/custom_platform_view",
                    TestViewFactory(registrar.messenger()))
        }
    }
    override fun onDetachedFromEngine(binding: FlutterPlugin.FlutterPluginBinding) {
    }
}

在Ap测试你的自卑程度p 中 MainActivity中注册：

package com.example.flutter_android_view
import io.flutter.embedding.android.FlutterActivity
import io.flutter.embedding.engine.FlutterEngine
class MainActivity: FlutterActivity() {
    override fun configureFlutterEngine(flutterEngine: FlutterEngine) {
        super.configureFlutterEngine(flutterEngine)
        flutterEngine.plugins.add(TestViewPlugin())
    }
}

最后的目录结构按钮的工作原理

嵌入fljvm垃圾回收机制utter

import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
class AndroidViewPage extends StatelessWidget {
  const AndroidViewPage({Key? key}) : super(key: key);
  @override
  Widget build(BuildContext context) {
    String? title = "androidView";
    return Scaffold(
      appBar: AppBar(title: Text(title ?? ''),),
      body: Center(
        child:iosView(),
      ),
    );
  }
  Widget iosView() {
    if(defaultTargetPlatform == TargetPlatform.android){
      return  const AndroidView(
        viewType: 'plugins.flutter.io/custom_platform_view',
      );
    }else {
      return Container();
    }
  }
}

运用android模拟按钮英文器运转结果

2. Flutter向android传值

AndroidView(
  viewType: 'plugins.flutter.io/custom_platform_view',
   creationParams: {'text': 'Flutter传给Android中TextView的参数'},
   creationParamsCodec: StandardMessageCodec(),
);

这里viewType就是咱们注册的时分运用的标识符。creationParams为创测试仪立AndroidView时带的参数。creationParamsCodec：将creationParamsjvm原理编码后再发送给平台侧，它应该与传递给构造函数的编解码器匹配。

咱们在Android项目中TestView判别是jvm是什么否传递了参数

init {
    args?.also {
        textView.text = it["text"] as String
    }
}

咱们在运转中经过按钮点击改变AndroidView的内容

static const platform = MethodChannel('com.flutter.test.TestView');

咱们在flutter页面定义一个办法通道

RaisedButton( child: const Text('传递参数给原生View'), onPressed: () { platform.invokeMethod('userInfo', {'name': 'Jack', 'city': "New York"}); },

点击的时分传参给Android页面,咱们在onMethodCall办测试仪法中获取咱们的参数

override fun onMethodCall(call: MethodCall, result: MethodChannel.Result) {
    if (call.method == "userInfo") {
        val name = call.argument("name") as String?
        val city = call.argument("city") as String?
        textView.text = "my Name is：,$name,from：$city"
    } else {
        result.notImplemented()
    }
}

3. 小结

关于 android中view的传值逻辑根本和之前的iOS页面差不多，逻辑上都是经过viewID来标记唯一性来确定，依据一些key，method办法等进行交互回调函数的彼此回调实现通讯。