安卓通知

Question

您好，我正在尝试构建一个 android 应用程序，当应用程序在后台运行时我必须显示通知。但是当应用程序在后台运行时，我有一个问题通知没有显示。请帮助

这是我的活动代码

public class TestActivity extends Activity {
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    Intent intent = new Intent(TestActivity.this, NotifyService.class);
    TestActivity.this.startService(intent);
}

这里是服务的代码

  public class NotifyService extends Service {

final static String ACTION = "NotifyServiceAction";
final static String STOP_SERVICE = "";
final static int RQS_STOP_SERVICE = 1;
boolean running = false;
NotifyServiceReceiver notifyServiceReceiver;

private static final int MY_NOTIFICATION_ID=1;
private NotificationManager notificationManager;
private Notification myNotification;
private final String myBlog = "http://android-er.blogspot.com/";

  @Override
public void onCreate() {

    notifyServiceReceiver = new NotifyServiceReceiver();
    super.onCreate();
}

@Override
public int onStartCommand(Intent intent, int flags, int startId) {


    IntentFilter intentFilter = new IntentFilter();
    intentFilter.addAction(ACTION);
    registerReceiver(notifyServiceReceiver, intentFilter);

// Send Notification
    notificationManager =
            (NotificationManager)getSystemService(Context.NOTIFICATION_SERVICE);
    myNotification = new Notification(R.drawable.ic_launcher,
            "Notification!",
            System.currentTimeMillis()+10000);
    Context context = getApplicationContext();
    String notificationTitle = "Exercise of Notification!";
    String notificationText = "http://android-er.blogspot.com/";
    Intent myIntent = new Intent(Intent.ACTION_VIEW, Uri.parse(myBlog));
    PendingIntent pendingIntent = PendingIntent.getActivity(getApplicationContext(), 0, myIntent,
            PendingIntent.FLAG_CANCEL_CURRENT);

    myNotification.defaults |= Notification.DEFAULT_SOUND;
    myNotification.flags |= Notification.FLAG_AUTO_CANCEL;
    myNotification.setLatestEventInfo(context,
            notificationTitle,
            notificationText,
            pendingIntent);
    notificationManager.notify(MY_NOTIFICATION_ID, myNotification);

    return super.onStartCommand(intent, flags, startId);
}

@Override
public void onDestroy() {

    this.unregisterReceiver(notifyServiceReceiver);
    super.onDestroy();
}

@Override
public IBinder onBind(Intent arg0) {

    return null;
}


public class NotifyServiceReceiver extends BroadcastReceiver{

    @Override
    public void onReceive(Context arg0, Intent arg1) {
        // TODO Auto-generated method stub
        int rqs = arg1.getIntExtra("RQS", 0);
        if (rqs == RQS_STOP_SERVICE){
            stopSelf();
        }
    }
  }
}                                                 

这是我的接收者的代码

public void onReceive(Context context, Intent intent) {
    // TODO Auto-generated method stub

    if(intent.getAction().equals(BOOT_COMPLETED_ACTION)){
        Intent myIntent = new Intent(context, NotifyService.class);
        context.startService(myIntent);
    }

最后这是我的清单

<service android:name=".Test.NotifyService"
        android:enabled="true"
        android:exported="true"/>
    <receiver android:name=".Test.AutoStartNotifyReceiver"
        android:enabled="true"
        android:label="@string/app_name">
        <intent-filter>
            <action android:name="android.intent.action.BOOT_COMPLETED" />
            <category android:name="android.intent.category.DEFAULT" />
        </intent-filter>
    </receiver>

Answer 1

现在您正在使用未绑定服务（未绑定服务无法识别该应用程序是否在后台运行）。

所以我给你的建议是你应该使用绑定服务（bindService），bindservie 可以识别应用程序何时关闭或重新打开。

在使用绑定服务时，在 unBind() 方法中添加您的通知代码（这意味着您正在通知应用程序何时关闭并在后台运行）。

您将在此链接http://developer.android.com/guide/components/bound-services.html找到绑定服务示例和其他详细信息

Answer 2

Notification(int icon, CharSequence tickerText, long when) 和 Notification.setLatestEventInfo(...)' are both deprecated APIs. Furthermore,setLatestEventInfo` 已从 API 中移除。

考虑使用Notification.Builder 类来创建Notification 对象：http://developer.android.com/guide/topics/ui/notifiers/notifications.html

Answer 3

Android 中没有直接的方法可以知道应用程序是否在后台。我发现了这个技巧：

服务并不是真正需要的。扩展一个应用程序类：

public class Application extends android.app.Application {
    private static boolean activityVisible = true;
    public static boolean isActivityVisible() {
        return activityVisible;
    }

    public static void activityResumed() {
        activityVisible = true;
    }

    public static void activityPaused() {
        activityVisible = false;
    } 
}

然后，在您的活动中，将代码放入您的 onPause() 和 onResume() 方法中：

final int mNotificationId = 1234567;
NotificationManager mNotifyMgr;

@Override
public void onPause() {
    super.onPause();
    Application.activityPaused();
    mNotifyMgr = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
    Intent resultIntent = new Intent(getApplicationContext(), MainActivity.class);
    PendingIntent resultPendingIntent = PendingIntent.getActivity(getApplicationContext(), mNotificationId, resultIntent, 0);
    mBuilder = new NotificationCompat.Builder(this)
            .setSmallIcon(R.drawable.logo)
            .setContentTitle(getResources().getString(R.string.app_name))
            .setContentIntent(resultPendingIntent)
            .setContentText("Your Text");
    mNotifyMgr.notify(mNotificationId, mBuilder.build());
}

@Override
public void onResume() {
    super.onResume();
    Application.activityResumed();
    mNotifyMgr.cancel(mNotificationId); //we don't need a notification if the app is visible.
}

在清单中，您需要指定您正在使用 Application 类：

<application
        android:name=".Application"
        ...>