Flutter升級及開發問題彙總

開發集成環境
[✓] Flutter (Channel stable, v1.12.13+hotfix.9, on Mac OS X 10.14.6 18G103, locale zh-Hans-CN)

一、簡述Flutter集成到Android原生項目
二、Android原生以AAR形式集成Flutter項目
三、Flutter與原生(Android/IOS)的消息通信
四、Flutter中如何使用原生控件/組件
五、Flutter狀態管理Provider與Redux
六、Flutter升級及開發中遇到的問題彙總

此前記錄的關於升級到Flutter V1.12與之前版本異同點

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不再建議使用

3. 原來的FlutterActivity包路徑替換

   由io.flutter.app.FlutterActivity 替換成 io.flutter.embedding.android.FlutterActivity

4. 修改啓動FlutterActivity方法

   官方啓動方式：

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

   稍微走進FlutterActivity源碼你會發現：

     @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);
       }
   

   可以看出這個withNewEngine方法傳的一直都是FlutterActivity.class，然後new一個NewEngineIntentBuilder，而NewEngineIntentBuilder的構造函數是protected，不是子類沒法直接new。那隻好繼承NewEngineIntentBuilder這個類，重寫它的構造函數。

   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);
           //主要加入這句話實現透明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. 啓動FlutterActivity過渡的圖片

   爲了啓動了FlutteActivity後加載flutter過程中顯示的圖片，沒設置一般是白屏或者黑屏。
   如果你之前設置了android:name="io.flutter.app.android.SplashScreenUntilFirstFrame".需要移除掉.

   添加如下代碼：

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

6. flutter出現黑屏無法顯示

   需要在flutter的main函數中，runApp前調用如下方法即可：

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

7. MethodChannel的應用

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

   改成：

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