Question

我正在使用Firebase作业调度程序api在后台运行服务。在棉花糖中，它可以正常工作，但是在使用Oreo设备时却无法正常工作。它显示错误或警告消息，例如

2019-02-04 14：20：22.285 2525-5699 /？ E / NetworkScheduler：删除任务应用的Play服务SDK版本不支持AndroidO。更新SDK或降低应用程序的目标SDK版本。包： com.webappclouds.jobserviceexample

我已经完成了git hub中的firebase作业调度程序api步骤中提到的内容。

MainActiviy.java

package com.webappclouds.jobserviceexample;    
import android.app.job.JobInfo;    
import android.app.job.JobScheduler;    
import android.content.ComponentName;    
import android.support.v7.app.AppCompatActivity;    
import android.os.Bundle;    
import android.util.Log;    
import android.view.View;    
import android.widget.Button;    
import com.firebase.jobdispatcher.Constraint;    
import com.firebase.jobdispatcher.FirebaseJobDispatcher;    
import com.firebase.jobdispatcher.GooglePlayDriver;    
import com.firebase.jobdispatcher.Job;    
import com.firebase.jobdispatcher.Lifetime;    
import com.firebase.jobdispatcher.RetryStrategy;    
import com.firebase.jobdispatcher.Trigger;       
public class MainActivity extends AppCompatActivity {

String TAG="MAIN ACTIVITY";
FirebaseJobDispatcher dispatcher;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    dispatcher = new FirebaseJobDispatcher(new GooglePlayDriver(this));

}

public void startjob(View view) {
    Log.d(TAG, "startjob: ");
    Job job = createJob(dispatcher);
    dispatcher.mustSchedule(job);

}

public void stopjob(View view) {
    Log.d(TAG, "cancelJob: ");
    dispatcher.cancelAll();
}

public Job createJob(FirebaseJobDispatcher dispatcher) {
    Log.d(TAG, "createJob: ");
    Job job = dispatcher.newJobBuilder()
            // persist the task across boots
            .setLifetime(Lifetime.FOREVER)
            // Call this service when the criteria are met.
            .setService(MakeService.class)
            // unique id of the task
            .setTag("LocationJob")
            .setReplaceCurrent(true)
            // We are mentioning that the job is not periodic.
            .setRecurring(true)
           // Run between 30 - 60 seconds from now.
            .setTrigger(Trigger.executionWindow(0, 0))
            .setRetryStrategy(RetryStrategy.DEFAULT_LINEAR)
            // .setTrigger(Trigger.NOW)
            //Run this job only when the network is avaiable.
            .setConstraints(Constraint.ON_ANY_NETWORK)
            .build();
    return job;
}
}

MakeService.java

package com.webappclouds.jobserviceexample;


import android.content.Context;
import android.content.Intent;
import android.os.Handler;
import android.os.SystemClock;
import android.util.Log;


import com.firebase.jobdispatcher.JobService;

import java.util.logging.LogRecord;

import static android.content.ContentValues.TAG;

public class MakeService extends JobService {
    boolean jobintentService=false;
    Handler handler;

    @Override
    public void onCreate() {
        super.onCreate();
        handler= new Handler();
    }


    @Override
    public boolean onStartJob(com.firebase.jobdispatcher.JobParameters job) {
        Log.d(TAG, "onStartJob: ");
        handler.postDelayed(new Runnable() {
            @Override
            public void run() {
                Log.d(TAG, "run: Handler");
                handler.postDelayed(this,10000);
            }
        },10000);
        return true;
    }

    @Override
    public boolean onStopJob(com.firebase.jobdispatcher.JobParameters job) {
        Log.d(TAG, "onStopJob: ");
        return true;
    }

}

清单

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

    <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED"/>
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <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">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <service
            android:exported="false"
            android:permission=""
            android:name=".MakeService">
            <intent-filter>
                <action android:name="com.firebase.jobdispatcher.ACTION_EXECUTE"/>
            </intent-filter>
        </service>
    </application>

</manifest>

构建（项目）

buildscript {

    repositories {
        google()
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.3.0'
        classpath 'com.google.gms:google-services:4.2.0'


        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        google()
        jcenter()
    }
}

task clean(type: Delete) {
    delete rootProject.buildDir
}

构建（应用）

apply plugin: 'com.android.application'

android {
    compileSdkVersion 28
    defaultConfig {
        applicationId "com.webappclouds.jobserviceexample"
        minSdkVersion 21
        targetSdkVersion 28
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation 'com.android.support:appcompat-v7:28.0.0'
    implementation 'com.android.support.constraint:constraint-layout:1.1.3'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'com.android.support.test:runner:1.0.2'
    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
    implementation 'com.firebase:firebase-jobdispatcher:0.5.2'

}

我希望它能正常工作，但我不知道发生了什么。

**解决方案** 这是由于版本实施'com.firebase：firebase-jobdispatcher：0.8.5' 我更新了它，从现在开始工作

Answer 1

错误消息确实可以解决问题

要么更新SDK，要么降低应用程序的目标SDK版本。包： com.webappclouds.jobserviceexample

从0.5.2

更新您的媒体库

implementation 'com.firebase:firebase-jobdispatcher:0.8.5'

我还注意到您的清单上有一个空的权限值，请将其删除。

android:permission=""

让我知道这是否有帮助

我建议您迁移到WorkManager，因为它是向后兼容和更简单的API。使用此库 all 时，您的API级别限制会得到解决（限制与安全性不同）。

您可以在此处找到一个简单的工作流程示例：

https://developer.android.com/topic/libraries/architecture/workmanager/basics#java

文档：

https://developer.android.com/topic/libraries/architecture/workmanager/

我建议您同时阅读两者。

Android Oreo背景执行限制：https://www.youtube.com/watch?v=Pumf_4yjTMc

Answer 2

请查看有关Firebase JobDispatcher here的官方Android文档：

WorkManager是用于调度和执行可延期的库 Android中的后台工作。这是推荐的替代品 Firebase JobDispatcher。以下指南将引导您完成将Firebase JobDispatcher实施迁移到的过程工作管理器。

Firebase作业调度程序无法在Oreo设备上运行

2 个答案: