Flutter Android启动源码分析（一）

最新推荐文章于 2024-04-22 03:36:52 发布

原创

最新推荐文章于 2024-04-22 03:36:52 发布 · 480 阅读

0 ·

CC 4.0 BY-SA版权

文章标签：

#android #flutter

本文分析了Flutter在Android上的启动过程，从FlutterApplication的startInitialization到FlutterActivity的生命周期，特别是configureFlutterEngine方法中插件的注册。FlutterActivity通过FlutterActivityAndFragmentDelegate管理生命周期，并在onCreate中设置窗口透明度。后续文章将深入探讨FlutterActivityAndFragmentDelegate的细节。

前言

版本：Flutter 1.20.4 stable

这个系列主要讲解在Flutter的项目中，Android 从启动到加载Flutter等一系列的过程。

本文主要是对FlutterApplication的startInitialization方法及FlutterActivity整个类源码的分析

Application

<application
        android:name="io.flutter.app.FlutterApplication"
        android:label="flutter_channel"
        android:icon="@mipmap/ic_launcher">
        

public class FlutterApplication extends Application {
  @Override
  @CallSuper
  public void onCreate() {
    super.onCreate();
    FlutterMain.startInitialization(this);
  }
}

在Android项目的AndroidManifest.xml中指定了application为FlutterApplication，主要是一个初始化操作

最终会调用FlutterLoader类中的startInitialization方法

public void startInitialization(@NonNull Context applicationContext, @NonNull Settings settings) {
    if (this.settings != null) {
      return;
    }
    if (Looper.myLooper() != Looper.getMainLooper()) {
      throw new IllegalStateException("startInitialization must be called on the main thread");
    }
    applicationContext = applicationContext.getApplicationContext();
    this.settings = settings;
    long initStartTimestampMillis = SystemClock.uptimeMillis();
    initConfig(applicationContext);
    initResources(applicationContext);
    System.loadLibrary("flutter");
    VsyncWaiter.getInstance(
            (WindowManager) applicationContext.getSystemService(Context.WINDOW_SERVICE))
        .init();
    long initTimeMillis = SystemClock.uptimeMillis() - initStartTimestampMillis;
    FlutterJNI.nativeRecordStartTimestamp(initTimeMillis);
  }

加载Flutter引擎的本机库以启用后续的JNI调用
开始定位和打开应用程序APK中打包的Dart资源

FlutterApplication不做过多分析，就是一些资源的初始化和so库加载的一些操作

FlutterActivity

class MainActivity : FlutterActivity(){}

 public class FlutterActivity extends Activity
    implements FlutterActivityAndFragmentDelegate.Host, LifecycleOwner {
 
 public FlutterActivity() {
    lifecycle = new LifecycleRegistry(this);
  }

它是继承Activity并实现了FlutterActivityAndFr