Android 9.0进入后台或者锁屏时保活

在Android9.0中会默认禁止后台继续执行任务操作,例如 Android 9 设备用户有锁屏后采集音频或视频的需求，可以在锁屏或退至后台前起一个 Service，并在退出锁屏或返回前台前终止 Service

具体代码如下

public class KeepAppLifeService extends Service {
    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }

    private NotificationManager notificationManager;
    private String notificationId = "keepapplifeid";
    private String notificationName = "keepapplifename";

    @Override
    public void onCreate() {
        super.onCreate();
        notificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
        //创建NotificationChannel
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            NotificationChannel channel = new NotificationChannel(notificationId, notificationName, NotificationManager.IMPORTANCE_HIGH);
            notificationManager.createNotificationChannel(channel);
        }
        startForeground(1, getNotification());
    }

    private Notification getNotification() {
        Notification.Builder builder = new Notification.Builder(this)
                .setSmallIcon(R.mipmap.ic_launcher)
                .setContentTitle("App")
                .setContentText("后台运行中");
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            builder.setChannelId(notificationId);
        }
        return builder.build();
    }
}