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android - 使用 Service 运行后台并创建通知

转载 作者：IT王子 更新时间：2023-10-28 23:51:59 24 4
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我希望我的应用程序在单击按钮时启动服务，并且服务应该在后台运行以在一天中的特定时间显示通知。我有以下代码来执行此操作。但它显示了我不明白的错误。我是 Android 新手，这是我第一个使用 Service 的应用程序。任何帮助，将不胜感激。提前致谢。

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.newtrial"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="18" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.example.newtrial.CreateNotificationActiviy"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity
            android:name="com.example.newtrial.ResultActivity"
            android:label="@string/title_activity_result" >

        </activity>

        <service android:enabled="true" android:name=".UpdaterServiceManager" />

    </application>

</manifest>

CreateNotificationActiviy.java

package com.example.newtrial;

import android.os.Bundle;
import android.app.Activity;
import android.app.Notification;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.content.Intent;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class CreateNotificationActiviy extends Activity {

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

        Button b=(Button)findViewById(R.id.button1);
        b.setOnClickListener(new OnClickListener(){

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub      
                startService(new Intent(CreateNotificationActiviy.this, UpdaterServiceManager.class));
            }

        });

    }

    public void createNotification(View view) {
        // Prepare intent which is triggered if the
        // notification is selected
        Intent intent = new Intent(this, ResultActivity.class);
        PendingIntent pIntent = PendingIntent.getActivity(this, 0, intent, 0);

        // Build notification
        // Actions are just fake
        Notification noti = new Notification.Builder(this)
            .setContentTitle("Notification Title")
            .setContentText("Click here to read").setSmallIcon(R.drawable.ic_launcher)
            .setContentIntent(pIntent)
            .build();
        NotificationManager notificationManager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
        // hide the notification after its selected
        noti.flags |= Notification.FLAG_AUTO_CANCEL;

        notificationManager.notify(0, noti);

      } 

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.create_notification_activiy, menu);
        return true;
    }

}

UpdaterServiceManager.java

package com.example.newtrial;

import java.util.Calendar;
import java.util.Timer;
import java.util.TimerTask;

import android.app.AlertDialog;
import android.app.Notification;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.os.IBinder;
import android.util.Log;
import android.view.View;

public class UpdaterServiceManager extends Service {

    private final int UPDATE_INTERVAL = 60 * 1000;
    private Timer timer = new Timer();
    private static final int NOTIFICATION_EX = 1;
    private NotificationManager notificationManager;
    CreateNotificationActiviy not;

    public UpdaterServiceManager() {
        not=new CreateNotificationActiviy();
    }

    @Override
    public IBinder onBind(Intent intent) {
        // TODO Auto-generated method stub
        return null;
    }

    @Override
    public void onCreate() {
        // code to execute when the service is first created
        super.onCreate();
        Log.i("MyService", "Service Started.");
        showNotification();
    }

    public void showNotification()
    {
        final Calendar cld = Calendar.getInstance();

        int time = cld.get(Calendar.HOUR_OF_DAY);
        if(time>12)
        {
                  not.createNotification(null); 

        }
        else
        {
            AlertDialog.Builder alert=new AlertDialog.Builder(this);
            alert.setMessage("Not yet");
            alert.setTitle("Error");
            alert.setPositiveButton("OK", null);
            alert.create().show();
        }
    }

    @Override
    public void onDestroy() {
        if (timer != null) {
            timer.cancel();
        }
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startid) 
    {
        return START_STICKY;
    }

    private void stopService() {
        if (timer != null) timer.cancel();
    }

}

ResultActivity.java

package com.example.newtrial;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.widget.TextView;

public class ResultActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_result);
        TextView tv=(TextView)findViewById(R.id.textView1);
        tv.setText("After notification is clicked" );
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.result, menu);
        return true;
    }

}

Logcat

12-10 12:14:04.286: I/Process(872): Sending signal. PID: 872 SIG: 9
12-10 12:14:11.774: I/MyService(893): Service Started.
12-10 12:14:12.094: D/AndroidRuntime(893): Shutting down VM
12-10 12:14:12.094: W/dalvikvm(893): threadid=1: thread exiting with uncaught exception (group=0x414c4700)
12-10 12:14:12.124: E/AndroidRuntime(893): FATAL EXCEPTION: main
12-10 12:14:12.124: E/AndroidRuntime(893): java.lang.RuntimeException: Unable to create service com.example.newtrial.UpdaterServiceManager: android.view.WindowManager$BadTokenException: Unable to add window -- token null is not for an application
12-10 12:14:12.124: E/AndroidRuntime(893):  at android.app.ActivityThread.handleCreateService(ActivityThread.java:2587)
12-10 12:14:12.124: E/AndroidRuntime(893):  at android.app.ActivityThread.access$1600(ActivityThread.java:141)
12-10 12:14:12.124: E/AndroidRuntime(893):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1338)
12-10 12:14:12.124: E/AndroidRuntime(893):  at android.os.Handler.dispatchMessage(Handler.java:99)
12-10 12:14:12.124: E/AndroidRuntime(893):  at android.os.Looper.loop(Looper.java:137)
12-10 12:14:12.124: E/AndroidRuntime(893):  at android.app.ActivityThread.main(ActivityThread.java:5103)
12-10 12:14:12.124: E/AndroidRuntime(893):  at java.lang.reflect.Method.invokeNative(Native Method)
12-10 12:14:12.124: E/AndroidRuntime(893):  at java.lang.reflect.Method.invoke(Method.java:525)
12-10 12:14:12.124: E/AndroidRuntime(893):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
12-10 12:14:12.124: E/AndroidRuntime(893):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
12-10 12:14:12.124: E/AndroidRuntime(893):  at dalvik.system.NativeStart.main(Native Method)
12-10 12:14:12.124: E/AndroidRuntime(893): Caused by: android.view.WindowManager$BadTokenException: Unable to add window -- token null is not for an application
12-10 12:14:12.124: E/AndroidRuntime(893):  at android.view.ViewRootImpl.setView(ViewRootImpl.java:563)
12-10 12:14:12.124: E/AndroidRuntime(893):  at android.view.WindowManagerGlobal.addView(WindowManagerGlobal.java:269)
12-10 12:14:12.124: E/AndroidRuntime(893):  at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:69)
12-10 12:14:12.124: E/AndroidRuntime(893):  at android.app.Dialog.show(Dialog.java:281)
12-10 12:14:12.124: E/AndroidRuntime(893):  at com.example.newtrial.UpdaterServiceManager.showNotification(UpdaterServiceManager.java:65)
12-10 12:14:12.124: E/AndroidRuntime(893):  at com.example.newtrial.UpdaterServiceManager.onCreate(UpdaterServiceManager.java:41)
12-10 12:14:12.124: E/AndroidRuntime(893):  at android.app.ActivityThread.handleCreateService(ActivityThread.java:2577)
12-10 12:14:12.124: E/AndroidRuntime(893):  ... 10 more

最佳答案

这个问题比较老了，但我希望这篇文章仍然可能对其他人有用。

TL;DR:使用AlarmManager调度任务，使用IntentService，见示例代码here ;

这个测试应用程序(和指令)是关于什么的:

简单的 helloworld 应用，每 2 小时向您发送一次通知。单击通知 - 在应用程序中打开辅助 Activity ；删除通知轨道。

什么时候使用:

一旦您需要按计划运行某些任务。我自己的案例:每天一次，我想从服务器获取新内容，根据我获得的内容编写通知并将其显示给用户。

做什么:

  1. 首先，我们创建2个activity:MainActivity，启动notification-service和NotificationActivity，通过点击通知启动:

    activity_main.xml

    <?xml version="1.0" encoding="utf-8"?>
    <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:padding="16dp">
        <Button
            android:id="@+id/sendNotifications"
            android:onClick="onSendNotificationsButtonClick"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Start Sending Notifications Every 2 Hours!" />
    </RelativeLayout>

    MainActivity.java

    public class MainActivity extends AppCompatActivity {
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
        }

        public void onSendNotificationsButtonClick(View view) {
            NotificationEventReceiver.setupAlarm(getApplicationContext());
        }   
    }

    NotificationActivity 是您可以想出的任何随机 Activity 。 注意!不要忘记将这两个 Activity 都添加到 AndroidManifest 中。

  2. 然后我们创建 WakefulBroadcastReceiver 广播接收器，我在上面的代码中调用了 NotificationEventReceiver。

    在这里，我们将设置 AlarmManager开火PendingIntent每 2 小时(或以任何其他频率)，并在 onReceive() 中指定此 Intent 的已处理操作方法。在我们的例子中 - 清醒地 开始 IntentService ，我们将在后面的步骤中指定。这个IntentService会为我们生成通知。

    此外，此接收器将包含一些辅助方法，例如创建 PendintIntents，我们稍后将使用这些方法

    NB1! 因为我正在使用 WakefulBroadcastReceiver ，我需要在 list 中添加额外权限:<uses-permission android:name="android.permission.WAKE_LOCK" />

    NB2! 我使用它是广播接收器的唤醒版本，因为我想确保设备在我的 IntentService 期间不会重新进入休眠状态。的操作。在 hello-world 中，这并不重要(我们的服务中没有长时间运行的操作，但想象一下，如果在此操作期间您必须从服务器获取一些相对较大的文件)。阅读有关设备唤醒的更多信息 here .

    NotificationEventReceiver.java

    public class NotificationEventReceiver extends WakefulBroadcastReceiver {

        private static final String ACTION_START_NOTIFICATION_SERVICE = "ACTION_START_NOTIFICATION_SERVICE";
        private static final String ACTION_DELETE_NOTIFICATION = "ACTION_DELETE_NOTIFICATION";
        private static final int NOTIFICATIONS_INTERVAL_IN_HOURS = 2;

        public static void setupAlarm(Context context) {
            AlarmManager alarmManager = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
            PendingIntent alarmIntent = getStartPendingIntent(context);
            alarmManager.setRepeating(AlarmManager.RTC_WAKEUP,
                    getTriggerAt(new Date()),
                    NOTIFICATIONS_INTERVAL_IN_HOURS * AlarmManager.INTERVAL_HOUR,
                    alarmIntent);
        }

        @Override
        public void onReceive(Context context, Intent intent) {
            String action = intent.getAction();
            Intent serviceIntent = null;
            if (ACTION_START_NOTIFICATION_SERVICE.equals(action)) {
                Log.i(getClass().getSimpleName(), "onReceive from alarm, starting notification service");
                serviceIntent = NotificationIntentService.createIntentStartNotificationService(context);
            } else if (ACTION_DELETE_NOTIFICATION.equals(action)) {
                Log.i(getClass().getSimpleName(), "onReceive delete notification action, starting notification service to handle delete");
                serviceIntent = NotificationIntentService.createIntentDeleteNotification(context);
            }

            if (serviceIntent != null) {
                startWakefulService(context, serviceIntent);
            }
        }

        private static long getTriggerAt(Date now) {
            Calendar calendar = Calendar.getInstance();
            calendar.setTime(now);
            //calendar.add(Calendar.HOUR, NOTIFICATIONS_INTERVAL_IN_HOURS);
            return calendar.getTimeInMillis();
        }

        private static PendingIntent getStartPendingIntent(Context context) {
            Intent intent = new Intent(context, NotificationEventReceiver.class);
            intent.setAction(ACTION_START_NOTIFICATION_SERVICE);
            return PendingIntent.getBroadcast(context, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT);
        }

        public static PendingIntent getDeleteIntent(Context context) {
            Intent intent = new Intent(context, NotificationEventReceiver.class);
            intent.setAction(ACTION_DELETE_NOTIFICATION);
            return PendingIntent.getBroadcast(context, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT);
        }
    }

  3. 现在让我们创建一个 IntentService实际创建通知。

    在那里，我们指定 onHandleIntent()这是对我们在 startWakefulService 中传递的 NotificationEventReceiver Intent 的响应方法。

    如果是删除操作 - 例如，我们可以将其记录到我们的分析中。如果是开始通知 Intent - 然后使用 NotificationCompat.Builder我们正在编写新的通知并通过 NotificationManager.notify 显示它.在撰写通知时，我们还为点击和删除操作设置待处理的 Intent 。相当容易。

    NotificationIntentService.java

    public class NotificationIntentService extends IntentService {

        private static final int NOTIFICATION_ID = 1;
        private static final String ACTION_START = "ACTION_START";
        private static final String ACTION_DELETE = "ACTION_DELETE";

        public NotificationIntentService() {
            super(NotificationIntentService.class.getSimpleName());
        }

        public static Intent createIntentStartNotificationService(Context context) {
            Intent intent = new Intent(context, NotificationIntentService.class);
            intent.setAction(ACTION_START);
            return intent;
        }

        public static Intent createIntentDeleteNotification(Context context) {
            Intent intent = new Intent(context, NotificationIntentService.class);
            intent.setAction(ACTION_DELETE);
            return intent;
        }

        @Override
        protected void onHandleIntent(Intent intent) {
            Log.d(getClass().getSimpleName(), "onHandleIntent, started handling a notification event");
            try {
                String action = intent.getAction();
                if (ACTION_START.equals(action)) {
                    processStartNotification();
                }
                if (ACTION_DELETE.equals(action)) {
                    processDeleteNotification(intent);
                }
            } finally {
                WakefulBroadcastReceiver.completeWakefulIntent(intent);
            }
        }

        private void processDeleteNotification(Intent intent) {
            // Log something?
        }

        private void processStartNotification() {
            // Do something. For example, fetch fresh data from backend to create a rich notification?

            final NotificationCompat.Builder builder = new NotificationCompat.Builder(this);
            builder.setContentTitle("Scheduled Notification")
                    .setAutoCancel(true)
                    .setColor(getResources().getColor(R.color.colorAccent))
                    .setContentText("This notification has been triggered by Notification Service")
                    .setSmallIcon(R.drawable.notification_icon);

            PendingIntent pendingIntent = PendingIntent.getActivity(this,
                    NOTIFICATION_ID,
                    new Intent(this, NotificationActivity.class),
                    PendingIntent.FLAG_UPDATE_CURRENT);
            builder.setContentIntent(pendingIntent);
            builder.setDeleteIntent(NotificationEventReceiver.getDeleteIntent(this));

            final NotificationManager manager = (NotificationManager) this.getSystemService(Context.NOTIFICATION_SERVICE);
            manager.notify(NOTIFICATION_ID, builder.build());
        }
    }

  4. 快完成了。现在，我还为 BOOT_COMPLETED、TIMEZONE_CHANGED 和 TIME_SET 事件添加广播接收器，以在设备重新启动或时区更改后重新设置我的 AlarmManager(例如，用户从美国飞往欧洲并且您不希望弹出通知在半夜，但对本地时间很敏感:-))。

    NotificationServiceStarterReceiver.java

    public final class NotificationServiceStarterReceiver extends BroadcastReceiver {

        @Override
        public void onReceive(Context context, Intent intent) {
            NotificationEventReceiver.setupAlarm(context);
        }
    }

  5. 我们还需要在 AndroidManifest 中注册我们所有的服务、广播接收器:

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

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

        <application
            android:allowBackup="true"
            android:icon="@mipmap/ic_launcher"
            android:label="@string/app_name"
            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=".notifications.NotificationIntentService"
                android:enabled="true"
                android:exported="false" />

            <receiver android:name=".broadcast_receivers.NotificationEventReceiver" />
            <receiver android:name=".broadcast_receivers.NotificationServiceStarterReceiver">
                <intent-filter>
                    <action android:name="android.intent.action.BOOT_COMPLETED" />
                    <action android:name="android.intent.action.TIMEZONE_CHANGED" />
                    <action android:name="android.intent.action.TIME_SET" />
                </intent-filter>
            </receiver>

            <activity
                android:name=".NotificationActivity"
                android:label="@string/title_activity_notification"
                android:theme="@style/AppTheme.NoActionBar"/>
        </application>

    </manifest>

就是这样!

这个项目的源代码你可以找到here .希望这篇文章对您有所帮助。

关于android - 使用 Service 运行后台并创建通知，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/20501225/

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