Flutter Android ERROR：ensureInitializationComplete 必须在 startInitialization 之后调用

Question

目前我正在尝试将 Flutter 应用添加到我的 android 应用中，但是当我尝试执行 Intent 时，应用崩溃并打印以下问题：

我遵循了这个指南here

我得到这个错误：

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.testappandroid/io.flutter.embedding.android.FlutterActivity}: java.lang.IllegalStateException: ensureInitializationComplete must be called after startInitialization
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2913)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3048)
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78)
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1808)
        at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loop(Looper.java:193)
        at android.app.ActivityThread.main(ActivityThread.java:6669)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
     Caused by: java.lang.IllegalStateException: ensureInitializationComplete must be called after startInitialization
        at io.flutter.view.FlutterMain.ensureInitializationComplete(FlutterMain.java:168)
        at io.flutter.embedding.android.FlutterActivityAndFragmentDelegate.initializeFlutter(FlutterActivityAndFragmentDelegate.java:177)
        at io.flutter.embedding.android.FlutterActivityAndFragmentDelegate.onAttach(FlutterActivityAndFragmentDelegate.java:140)
        at io.flutter.embedding.android.FlutterActivity.onCreate(FlutterActivity.java:399)
        at android.app.Activity.performCreate(Activity.java:7136)
        at android.app.Activity.performCreate(Activity.java:7127)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1271)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2893)

所以它说：ensureInitializationComplete 必须在 startInitialization 之后调用。一种解决方案是在 Flutter Activity 中调用 FlutterMain.startInitialization(this)。但这对我不起作用：

我的颤振活动：

public class MainActivity extends FlutterActivity {
  @Override
  protected void onCreate(Bundle savedInstanceState) {
FlutterMain.startInitialization(this);
    super.onCreate(savedInstanceState);
    GeneratedPluginRegistrant.registerWith(this);
  }
}

我的安卓应用AndroidManifest：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    package="com.example.testappandroid">
    <uses-permission android:name="android.permission.INTERNET" />
    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme"
        tools:ignore="GoogleAppIndexingWarning">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity
            android:name="io.flutter.embedding.android.FlutterActivity"
            android:theme="@style/AppTheme"
            android:configChanges="orientation|keyboardHidden|keyboard|screenSize|locale|layoutDirection|fontScale|screenLayout|density"
            android:hardwareAccelerated="true"
            android:windowSoftInputMode="adjustResize"
            android:exported="true">
            <meta-data
                android:name="io.flutter.Entrypoint"
                android:value="main"
                />
        </activity>

    </application>

</manifest>

我的颤振模块AndroidManifest：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
          package="com.example.testappflutter.host">

    <!-- The INTERNET permission is required for development. Specifically,
         flutter needs it to communicate with the running application
         to allow setting breakpoints, to provide hot reload, etc.
    -->
    <uses-permission android:name="android.permission.INTERNET"/>

    <!-- io.flutter.app.FlutterApplication is an android.app.Application that
         calls FlutterMain.startInitialization(this); in its onCreate method.
         In most cases you can leave this as-is, but you if you want to provide
         additional functionality it is fine to subclass or reimplement
         FlutterApplication and put your custom class here. -->
    <application
        android:name="io.flutter.app.FlutterApplication"
        android:label="testappflutter"
        android:icon="@mipmap/ic_launcher">
        <activity
            android:name=".MainActivity"
            android:launchMode="singleTop"
            android:theme="@style/LaunchTheme"
            android:configChanges="orientation|keyboardHidden|keyboard|screenSize|locale|layoutDirection|fontScale|screenLayout|density|uiMode"
            android:hardwareAccelerated="true"
            android:windowSoftInputMode="adjustResize">
            <!-- This keeps the window background of the activity showing
                 until Flutter renders its first frame. It can be removed if
                 there is no splash screen (such as the default splash screen
                 defined in @style/LaunchTheme). -->
            <meta-data
                android:name="io.flutter.app.android.SplashScreenUntilFirstFrame"
                android:value="true" />
            <intent-filter>
                <action android:name="android.intent.action.MAIN"/>
                <category android:name="android.intent.category.LAUNCHER"/>
            </intent-filter>
        </activity>
    </application>
</manifest>

通过这行代码，我尝试打开 FlutterActivtiy。这是在我的飞镖代码中调用 main() 函数：

Intent defaultFlutter = createDefaultIntent(activity);
activity.startActivity(defaultFlutter);

上面的代码应该是这样开始的：

void main() => runApp(MaterialApp(
  routes: {
    "/": (context) => TestWidget()
  }
));

所以我一步一步地按照指南将 Flutter 添加到现有的 android 应用程序。我忘记了什么吗？在我看来，flutter 应用程序的 AndroidManifest 可能需要一些更改？任何想法我做错了什么？

Answer 1

确保您导入正确的包：

import io.flutter.embedding.android.FlutterActivity;
import io.flutter.embedding.engine.FlutterEngine;

而不是

import io.flutter.app.FlutterActivity

在您的 MainActivity 中，因此您的 Main Activity 应如下所示：

package com.example.example
import io.flutter.embedding.android.FlutterActivity;
import io.flutter.embedding.engine.FlutterEngine;
class MainActivity: FlutterActivity() {

}

Answer 2

FlutterMain.startInitialization(this);

在Super.Create 之前添加此行

FlutterMain.startInitialization(this) //Added line
super.onCreate(savedInstanceState)
GeneratedPluginRegistrant.registerWith(this)

Answer 3

尽管有消息ensureInitializationComplete must be called after startInitialization，但不需要调用它。以这种方式运行 Flutter 活动：

FlutterMain.startInitialization(context)
startActivity(FlutterActivity.createDefaultIntent(context))

如果您遇到崩溃 NoClassDefFoundError（类 DefaultLifecycleObserver），请将此依赖项添加到您的 android 模块：

implementation 'android.arch.lifecycle:common-java8:1.1.0'