Flutter——在Android平台上的启动流程浅析

}

很简单，继续往里走

public static void startInitialization(@NonNull Context applicationContext) {

if (isRunningInRobolectricTest) {

return;

}

FlutterLoader.getInstance().startInitialization(applicationContext);

}

上面的方法用于初始化 native system（即C++），并最终会调用下面的方法：

我将说明以注释的形式写在下面

public void startInitialization(@NonNull Context applicationContext, @NonNull Settings settings) {

if (this.settings != null) {

return;

}

///确保运行在 主线程

if (Looper.myLooper() != Looper.getMainLooper()) {

throw new IllegalStateException(“startInitialization must be called on the main thread”);

}

// Ensure that the context is actually the application context.

final Context appContext = applicationContext.getApplicationContext();

this.settings = settings;

initStartTimestampMillis = SystemClock.uptimeMillis();

///配置 aotSharedLibraryName、flutterAssetsDir、

/// vmSnapshotData、isolateSnapshotData

///等参数

initConfig(appContext);

///初始化VsyncWaiter，并设置回调

/// 当vsync信号到来时，就调用我们设置的回调，最终会触发页面的刷新

VsyncWaiter.getInstance((WindowManager) appContext.getSystemService(Context.WINDOW_SERVICE))

.init();

// 子线程

///这里主要是抽取资源文件，

///加载 flutter（libflutter.so）代码

Callable initTask =

new Callable() {

@Override

public InitResult call() {

ResourceExtractor resourceExtractor = initResources(appContext);

System.loadLibrary(“flutter”);

// Prefetch the default font manager as soon as possible on a background thread.

// It helps to reduce time cost of engine setup that blocks the platform thread.

Executors.newSingleThreadExecuto