Флаттер java.io.File android.app.Activity.getExternalFilesDir (java.lang.String) 'для ссылки на пустой объект - PullRequest
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Флаттер java.io.File android.app.Activity.getExternalFilesDir (java.lang.String) 'для ссылки на пустой объект

0 голосов
/ 17 сентября 2018

После того, как я установил android_alarm_manager в свой проект, я получил эту ошибку .. 

I/AlarmService(24713): Starting AlarmService...
E/MethodChannel#plugins.flutter.io/android_alarm_manager(24713): Failed to handle method call
E/MethodChannel#plugins.flutter.io/android_alarm_manager(24713): java.lang.NullPointerException: Attempt to invoke virtual method 'java.io.File android.app.Activity.getExternalFilesDir(java.lang.String)' on a null object reference
E/MethodChannel#plugins.flutter.io/android_alarm_manager(24713):        at io.flutter.plugins.imagepicker.ImagePickerPlugin.registerWith(ImagePickerPlugin.java:27)
E/MethodChannel#plugins.flutter.io/android_alarm_manager(24713):        at io.flutter.plugins.GeneratedPluginRegistrant.registerWith(GeneratedPluginRegistrant.java:29)
E/MethodChannel#plugins.flutter.io/android_alarm_manager(24713):        at com.example.myapp.Application.registerWith(Application.java:18)
E/MethodChannel#plugins.flutter.io/android_alarm_manager(24713):        at io.flutter.plugins.androidalarmmanager.AlarmService.startAlarmService(AlarmService.java:65)
E/MethodChannel#plugins.flutter.io/android_alarm_manager(24713):        at io.flutter.plugins.androidalarmmanager.AndroidAlarmManagerPlugin.startService(AndroidAlarmManagerPlugin.java:75)
E/MethodChannel#plugins.flutter.io/android_alarm_manager(24713):        at io.flutter.plugins.androidalarmmanager.AndroidAlarmManagerPlugin.onMethodCall(AndroidAlarmManagerPlugin.java:52)
E/MethodChannel#plugins.flutter.io/android_alarm_manager(24713):        at io.flutter.plugin.common.MethodChannel$IncomingMethodCallHandler.onMessage(MethodChannel.java:191)
E/MethodChannel#plugins.flutter.io/android_alarm_manager(24713):        at io.flutter.view.FlutterNativeView.handlePlatformMessage(FlutterNativeView.java:163)
E/MethodChannel#plugins.flutter.io/android_alarm_manager(24713):        at android.os.MessageQueue.nativePollOnce(Native Method)
E/MethodChannel#plugins.flutter.io/android_alarm_manager(24713):        at android.os.MessageQueue.next(MessageQueue.java:143)
E/MethodChannel#plugins.flutter.io/android_alarm_manager(24713):        at android.os.Looper.loop(Looper.java:122)
E/MethodChannel#plugins.flutter.io/android_alarm_manager(24713):        at android.app.ActivityThread.main(ActivityThread.java:5253)
E/MethodChannel#plugins.flutter.io/android_alarm_manager(24713):        at java.lang.reflect.Method.invoke(Native Method)
E/MethodChannel#plugins.flutter.io/android_alarm_manager(24713):        at java.lang.reflect.Method.invoke(Method.java:372)
E/MethodChannel#plugins.flutter.io/android_alarm_manager(24713):        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:913)
E/MethodChannel#plugins.flutter.io/android_alarm_manager(24713):        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:708)                                      4.8s
?  To hot reload changes while running, press "r". To hot restart (and rebuild state), press "R".
An Observatory debugger and profiler on Mi 4i is available at: http://127.0.0.1:3860/
For a more detailed help message, press "h". To detach, press "d"; to quit, press "q".
E/flutter (24713): [ERROR:flutter/shell/common/shell.cc(181)] Dart Error: Unhandled exception:
E/flutter (24713): PlatformException(error, Attempt to invoke virtual method 'java.io.File android.app.Activity.getExternalFilesDir(java.lang.String)' on a null object reference, null)
E/flutter (24713): #0      JSONMethodCodec.decodeEnvelope (package:flutter/src/services/message_codecs.dart:149:7)
E/flutter (24713): #1      MethodChannel.invokeMethod (package:flutter/src/services/platform_channel.dart:279:18)
E/flutter (24713): <asynchronous suspension>
E/flutter (24713): #2      AndroidAlarmManager.initialize (package:android_alarm_manager/android_alarm_manager.dart:70:10)
E/flutter (24713): <asynchronous suspension>

Это мой pubspec.yaml

dependencies:
  dio: "^1.0.1"
  flutter:
    sdk: flutter
  local_auth: "^0.2.0"
  shared_preferences: "^0.4.0"
  http: "^0.11.3+16"
  path_provider: ^0.4.1
  image_picker: "^0.4.10"
  multi_image_picker: "1.0.51"
  datetime_picker_formfield: ^0.1.3
  pull_to_refresh: ^1.1.5
  connectivity: ^0.3.1
  sqflite : any
  location: ^1.4.1
  android_alarm_manager: ^0.2.1
  geolocator: '^1.7.0'

Мой main.dart

void main() async {
  final int msgId = 0;
  runApp(new LoginApp());
  await AndroidAlarmManager.initialize();
  await AndroidAlarmManager.periodic(
      const Duration(seconds: 5), msgId, autoResendReports);
}

void autoResendReports() {
  print("TEST");
  final DateTime now = new DateTime.now();
  final int isolateId = Isolate.current.hashCode;
  print(
      "[$now] Hello, world! isolate=$isolateId function='$autoResendReports'");
}

class LoginApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      title: '',
      theme: new ThemeData(
        primarySwatch: Colors.green,
      ),
      routes: routes,
    );
  }
}

Мой файл AndroidManifest 

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.myapp">

    <!-- 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"/>
    <uses-permission android:name="android.permission.USE_FINGERPRINT"/>
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />


    <!-- 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=".Application"
        android:label="MyApp"
        android:icon="@mipmap/ic_launcher2">
        <activity
            android:name=".MainActivity"
            android:launchMode="singleTop"
            android:theme="@style/LaunchTheme"
            android:configChanges="orientation|keyboardHidden|keyboard|screenSize|locale|layoutDirection|fontScale|screenLayout|density"
            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>
        <service
            android:name="io.flutter.plugins.androidalarmmanager.AlarmService"
            android:exported="false"/>
    </application>
</manifest>

Я все еще не могу настроить фоновый сервис для работы флаттера.Пожалуйста, помогите.

1 Ответ

0 голосов
/ 13 марта 2019

Я застрял в подобной проблеме на некоторое время, поэтому я попытался обойти, используя файл Java. Итак, в основном я делаю то, что я создал фоновую логику, которую я хочу, используя Java на стороне Android, что легко сделать. Затем я говорю с этой стороны от флаттера, используя MethodChannel. Моему приложению просто нужно запустить будильник, когда таймер приложения закончит отсчет даже в фоновом режиме. У меня все еще есть некоторые проблемы с передачей переменных в службу на стороне Android, что является незначительным, я думаю, но в целом фоновая вещь работала хорошо для меня.

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