android o android8.0 startforegroundservice startforegroundservice() did not then call service.star

解決context.startforegroundservice() did not then call service.startforeground()

原因：

1. Android 8.0 系統不允許背景應用建立背景服務，故隻能使用

   Context.startForegroundService()

   啟動服務
2. 建立服務後，應用必須在5秒内調用該服務的 

   startForeground()

    顯示一條可見通知，聲明有服務在挂着，不然系統會停止服務 + ANR 套餐送上。
3. Notification 要加 Channel，系統的要求。

解決步驟：

Service.java 中

@Override
    public void onCreate() {
        super.onCreate();
        if (Build.VERSION.SDK_INT>=Build.VERSION_CODES.O) {
            startFG();
        }
    }

    private void startFG() {
        NotificationBuilder builder = new NotificationBuilder(this);
        final Notification notification = builder.buildNotification();
        startForeground(NotificationBuilder.NOTIFICATION_ID, notification);
    }
           

NotificationBuilder.java      

public final class NotificationBuilder {
    public static final String NOTIFICATION_CHANNEL_ID = "com.demo.CHANNEL_ID";
    public static final int NOTIFICATION_ID = 0xD660;

    private final Context mContext;
    private final NotificationManager mNotificationManager;

    public NotificationBuilder(Context context) {
        mContext = context;
        mNotificationManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
    }

    public Notification buildNotification() {
        if (shouldCreateNowPlayingChannel()) {
            createNowPlayingChannel();
        }

        NotificationCompat.Builder builder = new NotificationCompat.Builder(mContext, NOTIFICATION_CHANNEL_ID);

        return builder.setSmallIcon(R.drawable.all_app_takeaway_icon)
                .setContentTitle("")
                .setContentTitle("")
                .setOnlyAlertOnce(true)
                .setVisibility(NotificationCompat.VISIBILITY_PUBLIC)
                .build();
    }

    @RequiresApi(api = Build.VERSION_CODES.O)
    private boolean nowPlayingChannelExists() {
        return mNotificationManager.getNotificationChannel(NOTIFICATION_CHANNEL_ID) != null;
    }

    private boolean shouldCreateNowPlayingChannel() {
        return Build.VERSION.SDK_INT >= Build.VERSION_CODES.O && !nowPlayingChannelExists();
    }

    @RequiresApi(api = Build.VERSION_CODES.O)
    private void createNowPlayingChannel() {
        final NotificationChannel channel = new NotificationChannel(
                NOTIFICATION_CHANNEL_ID,
                "目前播放",
                NotificationManager.IMPORTANCE_LOW);
        channel.setDescription("目前播放的電台");
        mNotificationManager.createNotificationChannel(channel);
    }
}
           

還要注意：

AndroidManifest.xml  中配置permission

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

啟動Service方法：

//背景啟動service
        if (Build.VERSION.SDK_INT>=Build.VERSION_CODES.O) {
            Intent serviceIntent = new Intent(this, DemoService.class);
            startForegroundService(serviceIntent);
        } else {
            Intent serviceIntent = new Intent(this, DemoService.class);
            startService(serviceIntent);
        }