android - 清除最近的任务后收不到广播

Question

我想制作一个应用程序，它会在接收到 wifi 状态更改的广播时做一些事情。如何编辑此代码以使服务在清除最近任务后也接收广播？ 请帮忙。谢谢

这是下面的代码：

public class IntentService extends Service {
    SharedPreferences sharedPreferences;
    SimpleDateFormat simpleDateFormat;
    BroadcastReceiver broadcastReceiver= new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            int wifiStateExtra=intent.getIntExtra(WifiManager.EXTRA_WIFI_STATE, 0);
            sharedPreferences.edit().putString(simpleDateFormat.format(new Date()),"  :"+ wifiStateExtra).apply();
                        Log.d("Wifi State", "  :"+wifiStateExtra +"   i :" +i);
        }
    };
    private int i;
    public IntentService() {
        super();
    }
    @Override
    public void onCreate() {
        super.onCreate();
        sharedPreferences = getSharedPreferences("test", MODE_PRIVATE);
        simpleDateFormat = new SimpleDateFormat("HH:mm:ss");
    }
    @Override
    public void onStart(@Nullable Intent intent, int startId) {
        super.onStart(intent, startId);
        IntentFilter intentFilter = new IntentFilter();
        intentFilter.addAction(WifiManager.WIFI_STATE_CHANGED_ACTION);
        registerReceiver(broadcastReceiver, intentFilter);
    }
    @Override
    public int onStartCommand(@Nullable Intent intent, int flags, int startId) {
        return START_STICKY;
    }
    @Override
    public void onTaskRemoved(Intent rootIntent) {
        Toast.makeText(getApplicationContext(), "onTaskRemoved called", Toast.LENGTH_LONG).show();
        startService(rootIntent);
        super.onTaskRemoved(rootIntent);
    }
    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }
}

标签： androidservicebroadcastreceiverandroid-recents

Answer 1

Nougat 及以上：我们必须使用 JobScheduler 和 JobService 进行连接更改。

我可以把这分成三个步骤。

在活动中注册 JobScheduler。此外，启动 JobService（服务来处理来自 JobScheduler 的回调。使用 JobScheduler 调度的请求最终会落在该服务的“onStartJob”方法上。）

public class NetworkConnectionActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_network_connection);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        scheduleJob();

    }


    @RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
    private void scheduleJob() {
        JobInfo myJob = new JobInfo.Builder(0, new ComponentName(this, NetworkSchedulerService.class))
                .setRequiresCharging(true)
                .setMinimumLatency(1000)
                .setOverrideDeadline(2000)
                .setRequiredNetworkType(JobInfo.NETWORK_TYPE_ANY)
                .setPersisted(true)
                .build();

        JobScheduler jobScheduler = (JobScheduler) getSystemService(Context.JOB_SCHEDULER_SERVICE);
        jobScheduler.schedule(myJob);
    }

    @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, NetworkSchedulerService.class));
        super.onStop();
    }

    @Override
    protected void onStart() {
        super.onStart();
        // Start service and provide it a way to communicate with this class.
        Intent startServiceIntent = new Intent(this, NetworkSchedulerService.class);
        startService(startServiceIntent);
    }
}

开始和完成工作的服务。

public class NetworkSchedulerService extends JobService implements
        ConnectivityReceiver.ConnectivityReceiverListener {

    private static final String TAG = NetworkSchedulerService.class.getSimpleName();

    private ConnectivityReceiver mConnectivityReceiver;

    @Override
    public void onCreate() {
        super.onCreate();
        Log.i(TAG, "Service created");
        mConnectivityReceiver = new ConnectivityReceiver(this);
    }



    /**
     * When the app's NetworkConnectionActivity is created, it starts this service. This is so that the
     * activity and this service can communicate back and forth. See "setUiCallback()"
     */
    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        Log.i(TAG, "onStartCommand");
        return START_NOT_STICKY;
    }


    @Override
    public boolean onStartJob(JobParameters params) {
        Log.i(TAG, "onStartJob" + mConnectivityReceiver);
        registerReceiver(mConnectivityReceiver, new IntentFilter(Constants.CONNECTIVITY_ACTION));
        return true;
    }

    @Override
    public boolean onStopJob(JobParameters params) {
        Log.i(TAG, "onStopJob");
        unregisterReceiver(mConnectivityReceiver);
        return true;
    }

    @Override
    public void onNetworkConnectionChanged(boolean isConnected) {
        String message = isConnected ? "Good! Connected to Internet" : "Sorry! Not connected to internet";
        Toast.makeText(getApplicationContext(), message, Toast.LENGTH_SHORT).show();

    }
}

最后，检查网络连接的接收器类发生了变化。

public class ConnectivityReceiver extends BroadcastReceiver {

    private ConnectivityReceiverListener mConnectivityReceiverListener;

    ConnectivityReceiver(ConnectivityReceiverListener listener) {
        mConnectivityReceiverListener = listener;
    }


    @Override
    public void onReceive(Context context, Intent intent) {
        mConnectivityReceiverListener.onNetworkConnectionChanged(isConnected(context));

    }

    public static boolean isConnected(Context context) {
        ConnectivityManager cm = (ConnectivityManager)
                context.getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo activeNetwork = cm.getActiveNetworkInfo();
        return activeNetwork != null && activeNetwork.isConnectedOrConnecting();
    }

    public interface ConnectivityReceiverListener {
        void onNetworkConnectionChanged(boolean isConnected);
    }
}

不要忘记在清单文件中添加权限和服务。

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

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


    <!-- Always required on api < 21, needed to keep a wake lock while your job is running -->
    <uses-permission android:name="android.permission.WAKE_LOCK"/>
    <!-- Required on api < 21 if you are using setRequiredNetworkType(int) -->
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
    <!-- Required on all api levels if you are using setPersisted(true) -->
    <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED"/>

    <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=".connectivity.NetworkConnectionActivity"
            android:theme="@style/AppTheme.NoActionBar">
            <intent-filter>
                <action android:name="android.intent.action.MAIN"/>

                <category android:name="android.intent.category.LAUNCHER"/>
            </intent-filter>
        </activity>


        <!-- Define your service, make sure to add the permision! -->
        <service
            android:name=".connectivity.NetworkSchedulerService"
            android:exported="true"
            android:permission="android.permission.BIND_JOB_SERVICE"/>
    </application>

</manifest>

请参阅以下链接以获取更多信息。 https://github.com/jiteshmohite/Android-Network-Connectivity

https://github.com/evant/JobSchedulerCompat

https://github.com/googlesamples/android-JobScheduler https://medium.com/@iiro.krankka/its-time-to-kiss-goodbye-to-your-implicit-broadcastreceivers-eefafd9f4f8a