开发集成环境
[✓] Flutter (Channel stable, v1.12.13+hotfix.9, on Mac OS X 10.14.6 18G103, locale zh-Hans-CN)

一、简述Flutter集成到Android原生项目
二、Android原生以AAR形式集成Flutter项目
三、Flutter与原生(Android/IOS)的消息通信
四、Flutter中如何使用原生控件/组件
五、Flutter状态管理Provider与Redux
六、Flutter升级及开发中遇到的问题汇总

此前记录的关于升级到Flutter V1.12与之前版本异同点

1. 不需要在Application中初始化

   去除FlutterMain.startInitialization(this); 初始化方法。

2. io.flutter.facade包已移除，flutterView不再建议使用

3. 原来的FlutterActivity包路径替换

   由io.flutter.app.FlutterActivity 替换成 io.flutter.embedding.android.FlutterActivity

4. 修改启动FlutterActivity方法

   官方启动方式：

   startActivity(
         FlutterActivity
           .withNewEngine()
           .initialRoute("/test")
           .build(currentActivity)
         );
   

   稍微走进FlutterActivity源码你会发现：

     @NonNull
     public static NewEngineIntentBuilder withNewEngine() {
       return new NewEngineIntentBuilder(FlutterActivity.class);
     }
   
     protected NewEngineIntentBuilder(@NonNull Class<? extends FlutterActivity> activityClass) {
         this.activityClass = activityClass;
       }
   
       @NonNull
       public Intent build(@NonNull Context context) {
         return new Intent(context, activityClass)
             .putExtra(EXTRA_INITIAL_ROUTE, initialRoute)
             .putExtra(EXTRA_BACKGROUND_MODE, backgroundMode)
             .putExtra(EXTRA_DESTROY_ENGINE_WITH_ACTIVITY, true);
       }
   

   可以看出这个withNewEngine方法传的一直都是FlutterActivity.class，然后new一个NewEngineIntentBuilder，而NewEngineIntentBuilder的构造函数是protected，不是子类没法直接new。那只好继承NewEngineIntentBuilder这个类，重写它的构造函数。

   改造如下：

   public class MyFlutterActivity extends FlutterActivity {
   
       public static void openFlutter(Activity activity, String routerUrl){
           Intent intent = MyFlutterActivity.withNewEngine()
                   .initialRoute(routerUrl)
                   .build(activity);
           //主要加入这句话实现透明Activity
           //intent.putExtra("background_mode","transparent");
           activity.startActivity(intent);
       }
   
       public static AhsEngineIntentBuilder withNewEngine() {
           return new AhsEngineIntentBuilder(MyFlutterActivity.class);
       }
   
       public static AhsEngineIntentBuilder withNewEngine(Class<? extends FlutterActivity> activityClass) {
           return new AhsEngineIntentBuilder(activityClass);
       }
   
       public static class AhsEngineIntentBuilder extends NewEngineIntentBuilder {
   
           protected AhsEngineIntentBuilder(Class<? extends FlutterActivity> activityClass) {
               super(activityClass);
           }
       }
   }
   

5. 启动FlutterActivity过渡的图片

   为了启动了FlutteActivity后加载flutter过程中显示的图片，没设置一般是白屏或者黑屏。
   如果你之前设置了android:name="io.flutter.app.android.SplashScreenUntilFirstFrame".需要移除掉.

   添加如下代码：

   <!-- 在所在的activity中加入 -->
   <meta-data
               android:name="io.flutter.embedding.android.SplashScreenDrawable"
               android:resource="@drawable/placehold_background" />
   

6. flutter出现黑屏无法显示

   需要在flutter的main函数中，runApp前调用如下方法即可：

   void main() {
     WidgetsFlutterBinding.ensureInitialized();
     runApp(MyApp());
   }
   

7. MethodChannel的应用

   MethodChannel(flutterEngine.dartExecutor.binaryMessenger, CHANNEL).setMethodCallHandler() 
   

   改成：

   MethodChannel(flutterEngine.dartExecutor, CHANNEL).setMethodCallHandler()