java - 当应用程序从后台删除时如何停止 JobService Scheduled？

Question

目前我正在使用一个应用程序，我的应用程序有一个功能，用户可以点击导航按钮，我的应用程序将启动谷歌地图。到现在为止都很好，我已经做到了。但我被卡住的事实是我希望我的应用程序执行一些任务。为了实现这一点，我使用了 JobService 并安排它每 5 秒运行一次，即使应用程序在后台也是如此。

当用户按下后退按钮然后在 onDestroy 方法中我取消了调度程序。但是，当应用程序通过滑动或按下十字图标从后台删除时，JobService 会继续运行，因为当它从后台删除时，操作系统可以调用或不调用 onDestroy 方法。当应用程序从后台删除时，如何停止计划的作业？

AndroidManifest.xml

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

    <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

    <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:name=".MyJobService" android:exported="true" android:permission="android.permission.BIND_JOB_SERVICE" />

    </application>

</manifest>

MyJobService 类

public class MyJobService extends JobService {

    @Override
    public boolean onStartJob(final JobParameters jobParameters) {
        Toast.makeText(getApplicationContext(), "Doing job", Toast.LENGTH_SHORT).show();
        jobFinished(jobParameters, true);
        return false;
    }

    @Override
    public boolean onStopJob(JobParameters jobParameters) {
        return false;
    }
}

这是我的主 Activity

public class MainActivity extends AppCompatActivity {

    private static final  int JOB_ID = 1;

    private JobInfo jobInfo;
    private JobScheduler scheduler;

    private Button navigateButton;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        ComponentName componentName = new ComponentName(this, MyJobService.class);
        JobInfo.Builder builder = new JobInfo.Builder(JOB_ID, componentName);
        builder.setPeriodic(5000);
        builder.setRequiredNetworkType(JobInfo.NETWORK_TYPE_ANY);
        // if true this job exists even after a system reboot...
        builder.setPersisted(false);


        jobInfo = builder.build();

        scheduler = (JobScheduler) getSystemService(JOB_SCHEDULER_SERVICE);
        scheduler.schedule(jobInfo);

        navigateButton = (Button) findViewById(R.id.navigate_button);

        navigateButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                StringBuffer url = new StringBuffer("https://www.google.com/maps/dir/?api=1");
                url.append("&origin=23.755736,90.374627");
                url.append("&destination=23.754047,90.371682");
                url.append("&travelmode=driving");
                Uri gmmIntentUri = Uri.parse(url.toString());
                Intent mapIntent = new Intent(Intent.ACTION_VIEW, gmmIntentUri);
                mapIntent.setPackage("com.google.android.apps.maps");
                startActivity(mapIntent);
            }
        });

    }

    @Override
    protected void onDestroy() {
        Toast.makeText(getApplicationContext(), "Destroy called.", Toast.LENGTH_SHORT).show();
        scheduler.cancel(JOB_ID);
        super.onDestroy();
    }

}

Answer 1

我认为您需要覆盖以下 onStop() 方法并放置 stopService() 命令来停止 JobService。

@Override
protected void onStop() {
    // A service can be "started" and/or "bound". In this case, it's "started" by this Activity
    // and "bound" to the JobScheduler (also called "Scheduled" by the JobScheduler). This call
    // to stopService() won't prevent scheduled jobs to be processed. However, failing
    // to call stopService() would keep it alive indefinitely.
    stopService(new Intent(this, MyJobService.class));
    super.onStop();
}