版本号0.1.54
看源码之前,我先去看下官方文档,对于其源码的设计说明,文中所说的原生都是指android
看完官方文档的说明,我有以下几个疑问
第一个:容器是怎么设计的?
第二个:native和flutter的channel的通道是如何设计的?
第三个:Flutter是适配层到底再做些什么?
中控中心FlutterBoost
单独拎出来讲讲,这个类比较简单,就是集合各个模块并让其初始化,同时也是该插件入口处,不管原生和flutter都一样,看源码也是从这里开始看起,但原生和flutter的初始化流程稍微有少许区别,主要还是因为原生是作为容器,flutter的容器是依赖于原生容器。
原生init
入口:/flutter_boost/example/android/app/src/main/java/com/taobao/idlefish/flutterboostexample/MyApplication.java
FlutterBoost.init从这里开始进入
FlutterBoost.init(new Platform() {
@Override
public Application getApplication() {
return MyApplication.this;
}
@Override
public boolean isDebug() {
return true;
}
@Override
public void openContainer(Context context, String url, Map<String, Object> urlParams, int requestCode, Map<String, Object> exts) {
PageRouter.openPageByUrl(context, url, urlParams, requestCode);
}
@Override
public IFlutterEngineProvider engineProvider() {
//注意这里 覆写了createEngine
return new BoostEngineProvider() {
@Override
public BoostFlutterEngine createEngine(Context context) {
return new BoostFlutterEngine(context, new DartExecutor.DartEntrypoint(
context.getResources().getAssets(),
FlutterMain.findAppBundlePath(context),
"main"), "/");
}
};
}
@Override
public int whenEngineStart() {
return ANY_ACTIVITY_CREATED;
}
});
BoostChannel.addActionAfterRegistered(new BoostChannel.ActionAfterRegistered() {
@Override
public void onChannelRegistered(BoostChannel channel) {
//platform view register should use FlutterPluginRegistry instread of BoostPluginRegistry
TextPlatformViewPlugin.register(FlutterBoost.singleton().engineProvider().tryGetEngine().getPluginRegistry());
}
});
}
上面大部分方法,做过android也知道是干嘛的,这里重点讲讲IFlutterEngineProvider这个接口,这里有3个方法,如下
/**
* a flutter engine provider
*/
public interface IFlutterEngineProvider {
/**
* create flutter engine, we just hold a single instance now
* @param context
* @return
*/
BoostFlutterEngine createEngine(Context context);
/**
* provide a flutter engine
* @param context
* @return
*/
BoostFlutterEngine provideEngine(Context context);
/**
* may return null
* @return
*/
BoostFlutterEngine tryGetEngine();
}
抽象成接口,根据项目的实际情况,开发者可以自己实现flutter引擎,或采用官方源码里自己的实现类即BoostEngineProvider,但想不明白 createEngine 和provideEngine 到底有何区别,到底为何弄成两个方法,不就是个提供个flutter引擎实例吗?
看了下createEngine的实现,主要加载实例BoostFlutterEngine,这个实例看名字也清楚是进行flutter引擎的初始化,设置了dart默认入口点即main,设置了路由起点及插件的声明注册一类
然后去看provideEngine方法的实现,代码较少,如下
@Override
public BoostFlutterEngine provideEngine(Context context) {
Utils.assertCallOnMainThread();
if (mEngine == null) {
FlutterShellArgs flutterShellArgs = new FlutterShellArgs(new String[0]);
FlutterMain.ensureInitializationComplete(
context.getApplicationContext(), flutterShellArgs.toArray());
mEngine = createEngine(context.getApplicationContext());
final IStateListener stateListener = FlutterBoost.sInstance.mStateListener;
if(stateListener != null) {
stateListener.onEngineCreated(mEngine);
}
}
return mEngine;
}
初始化flutter参数及增加一个回调,没什么特别之处,然后去翻了下flutter.jar的FlutterActivity源码,它的flutter引擎初始化最后是追踪到FlutterFragment,关键代码如下
flutter_boot android和flutter源码阅读记录(一) https://www.cppentry.com/bencandy.php?fid=100&id=265784