在 Android 中集成 Flutter

在 Android 中集成 Flutter

直接使用 Android Studio 是在现有应用中自动集成 Flutter 模块比较便捷的方法。在 Android Studio 中，你可以在一个项目中同时编写 Android 代码和 Flutter 代码，还可以继续使用各种常用的 IntelliJ Flutter 插件功能，例如 Dart 代码自动补全、热重载和 widget 检查器等。
https://flutter.cn/docs/development/add-to-app/android/add-flutter-screen?tab=custom-activity-launch-kotlin-tab

1.settings.gradle

include ':app'
setBinding(new Binding([gradle: this]))
evaluate(new File(
        settingsDir.parentFile,
        'flutter_demo_library/.android/include_flutter.groovy'
))
include ':flutter_demo_library'
project(':flutter_demo_library').projectDir = new File('../flutter_demo_library')

2.项目build.gradle

buildscript {
    ext.kotlin_version = '1.6.10'
    repositories {
        google()
        mavenCentral()
    }

    dependencies {
        classpath 'com.android.tools.build:gradle:7.1.2'
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
    }
}

allprojects {
    repositories {
        google()
        mavenCentral()
    }
}

3.appbuild.gradle

plugins {
    id 'com.android.application'
    id 'org.jetbrains.kotlin.android'
}

android {
    compileSdk 32

    defaultConfig {
        applicationId "com.lxt.flutter_demo_android"
        minSdk 23
        targetSdk 32
        versionCode 1
        versionName "1.0"

        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
    kotlinOptions {
        jvmTarget = '1.8'
    }
}

dependencies {
    implementation project(':flutter')

    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.6.10"
    implementation 'androidx.core:core-ktx:1.7.0'
    implementation 'androidx.appcompat:appcompat:1.3.0'
    implementation 'com.google.android.material:material:1.4.0'
    implementation 'androidx.constraintlayout:constraintlayout:2.0.4'
    implementation 'androidx.navigation:navigation-fragment-ktx:2.3.5'
    implementation 'androidx.navigation:navigation-ui-ktx:2.3.5'
    testImplementation 'junit:junit:4.13.2'
    androidTestImplementation 'androidx.test.ext:junit:1.1.3'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'
}

4.AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:tools="http://schemas.android.com/tools"
  package="com.lxt.flutter_demo_android">

  <application
    android:name=".MyApp"
    android:allowBackup="true"
    android:dataExtractionRules="@xml/data_extraction_rules"
    android:fullBackupContent="@xml/backup_rules"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:roundIcon="@mipmap/ic_launcher_round"
    android:supportsRtl="true"
    android:theme="@style/Theme.Flutter_demo_android"
    tools:targetApi="31" >
    <activity
      android:name=".MainActivity"
      android:exported="true"
      android:label="@string/app_name">
      <intent-filter>
        <action android:name="android.intent.action.MAIN" />

        <category android:name="android.intent.category.LAUNCHER" />
      </intent-filter>
    </activity>

    <activity
      android:name="io.flutter.embedding.android.FlutterActivity"
      android:configChanges="orientation|keyboardHidden|keyboard|screenSize|locale|layoutDirection|fontScale|screenLayout|density|uiMode"
      android:hardwareAccelerated="true"
      android:windowSoftInputMode="adjustResize"
      />
  </application>
</manifest>

5.MyFlutterEngineBinding.kt

package com.lxt.flutter_demo_android

import android.content.Context
import io.flutter.FlutterInjector
import io.flutter.embedding.engine.FlutterEngine
import io.flutter.embedding.engine.FlutterEngineCache
import io.flutter.embedding.engine.dart.DartExecutor

/**
 * 通过FlutterGroupEngine创建Engine
 */
fun Context.createGroupEngine(entryPointName: String): FlutterEngine {
    // 获取applicationContext
    val appContext = this.applicationContext as MyApp
    // 创建跳转点(enterPoint), enterPoint需要与Flutter中的方法名一致
    val entryPoint = DartExecutor.DartEntrypoint(
        FlutterInjector.instance().flutterLoader().findAppBundlePath(), entryPointName
    )
    // 创建FlutterEngine
    val engine = appContext.engines.createAndRunEngine(this, entryPoint)
    // 预加载，减少白屏或闪屏
    engine.dartExecutor.executeDartEntrypoint(entryPoint)
    // 放入缓存
    FlutterEngineCache.getInstance().put(entryPointName, engine)
    return engine
}

6.MyApplication -

package com.lxt.flutter_demo_android

import android.app.Application
import io.flutter.embedding.engine.FlutterEngineGroup

class MyApp : Application() {
    lateinit var engines: FlutterEngineGroup

    override fun onCreate() {
        super.onCreate()
        engines = FlutterEngineGroup(this)
    }
}

7.MainActivity

class MainActivity :Activity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        createGroupEngine("main")
        findViewById<TextView>(R.id.tv_login).setOnClickListener {
            this?.let { it1 ->
                it1.startActivity(FlutterActivity
                    .withCachedEngine("main")
                    .build(it1))
            }
          //  startActivity(FlutterActivity.createDefaultIntent(this))
        }
    }
}