使用服务运行后台并创建通知 [英] Using Service to run background and create notification
问题描述
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.我有以下代码来做到这一点.但它显示了我不明白的错误.我是 Android 新手，这是我第一个使用服务的应用程序.任何帮助，将不胜感激.提前致谢.
I want my app to start Service when the button is clicked and the Service should run in background to show a notification at a particular time of day. I have the following code to do this. But it shows errors which I don't understand. I am new to Android and this is my first app using Service. Any help would be appreciated. Thanks in advance.
AndroidManifest.xml
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
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
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
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;
}
}
日志猫
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
推荐答案
这个问题比较老，但我希望这篇文章仍然适用于其他人.
The question is relatively old, but I hope this post still might be relevant for others.
TL;DR:使用AlarmManager调度任务，使用IntentService，示例代码见这里;
TL;DR: use AlarmManager to schedule a task, use IntentService, see the sample code here;
简单的 helloworld 应用，每 2 小时向您发送一次通知.点击通知 - 在应用程序中打开辅助活动；删除通知轨道.
Simple helloworld app, which sends you notification every 2 hours. Clicking on notification - opens secondary Activity in the app; deleting notification tracks.
一旦您需要按计划运行某些任务.我自己的情况:每天一次，我想从服务器获取新内容，根据我获得的内容撰写通知并将其显示给用户.
Once you need to run some task on a scheduled basis. My own case: once a day, I want to fetch new content from server, compose a notification based on the content I got and show it to user.
首先，我们创建2个Activity:MainActivity，它启动notification-service和NotificationActivity，它会通过点击notification来启动:
First, let's create 2 activities: MainActivity, which starts notification-service and NotificationActivity, which will be started by clicking notification:
activity_main.xml
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
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());
}
}
并且 NotificationActivity 是您可以想出的任何随机活动.注意！不要忘记将这两个 Activity 添加到 AndroidManifest 中.
and NotificationActivity is any random activity you can come up with. NB! Don't forget to add both activities into AndroidManifest.
然后让我们创建 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 以每 2 小时(或以任何其他频率)触发 PendingIntent，并在 onReceive() 方法.在我们的例子中 - wakefully 启动 IntentService，我们将在后面的步骤中指定.这个 IntentService 会为我们生成通知.
Here, we'll set up AlarmManager to fire PendingIntent every 2 hours (or with any other frequency), and specify the handled actions for this intent in onReceive() method. In our case - wakefully start IntentService, which we'll specify in the later steps. This IntentService would generate notifications for us.
此外，这个接收器会包含一些辅助方法，比如创建 PendintIntents，我们稍后会用到
Also, this receiver would contain some helper-methods like creating PendintIntents, which we'll use later
NB1！ 因为我正在使用 WakefulBroadcastReceiver，我需要在清单中添加额外的权限:<uses-permission android:name="android.permission.WAKE_LOCK"/>
NB2！ 我使用广播接收器的唤醒版本，因为我想确保设备在我的 IntentService 操作期间不会回到睡眠状态.在 hello-world 中它不是那么重要(我们的服务中没有长时间运行的操作，但是想象一下，如果您必须在此操作期间从服务器获取一些相对较大的文件).在此处阅读有关设备唤醒的更多信息.
NB2! I use it wakeful version of broadcast receiver, as I want to ensure, that the device does not go back to sleep during my IntentService's operation. In the hello-world it's not that important (we have no long-running operation in our service, but imagine, if you have to fetch some relatively huge files from server during this operation). Read more about Device Awake here.
NotificationEventReceiver.java
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);
}
}
现在让我们创建一个 IntentService 来实际创建通知.
在那里，我们指定 onHandleIntent()，它是对我们在 startWakefulService 方法中传递的 NotificationEventReceiver 意图的响应.
There, we specify onHandleIntent() which is responses on NotificationEventReceiver's intent we passed in startWakefulService method.
如果是删除操作 - 例如，我们可以将其记录到我们的分析中.如果它是开始通知意图 - 那么通过使用 NotificationCompat.Builder 我们正在编写新通知并通过 NotificationManager.notify 显示它.在编写通知时，我们还为单击和删除操作设置了待处理的意图.相当简单.
If it's Delete action - we can log it to our analytics, for example. If it's Start notification intent - then by using NotificationCompat.Builder we're composing new notification and showing it by NotificationManager.notify. While composing notification, we are also setting pending intents for click and remove actions. Fairly Easy.
NotificationIntentService.java
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());
}
}
差不多完成了.现在我还为 BOOT_COMPLETED、TIMEZONE_CHANGED 和 TIME_SET 事件添加广播接收器以重新设置我的 AlarmManager，一旦设备重新启动或时区已更改(例如，用户从美国飞到欧洲并且您不希望弹出通知在半夜，但对本地时间很敏感:-)).
Almost done. Now I also add broadcast receiver for BOOT_COMPLETED, TIMEZONE_CHANGED, and TIME_SET events to re-setup my AlarmManager, once device has been rebooted or timezone has changed (For example, user flown from USA to Europe and you don't want notification to pop up in the middle of the night, but was sticky to the local time :-) ).
NotificationServiceStarterReceiver.java
NotificationServiceStarterReceiver.java
public final class NotificationServiceStarterReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
NotificationEventReceiver.setupAlarm(context);
}
}
我们还需要在 AndroidManifest 中注册我们所有的服务和广播接收器:
We need to also register all our services, broadcast receivers in AndroidManifest:
<?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！
您可以在此处找到此项目的源代码.希望这篇文章对您有所帮助.
That's it!
The source code for this project you can find here. I hope, you will find this post helpful.
这篇关于使用服务运行后台并创建通知的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
