startForegroundService() did not then call Service.startForeground()

项目在部分9.0手机运行报错：startForegroundService() did not then call Service.startForeground()

查资料发现：是因为8.0以上系统不允许后台应用启动后台服务。所以需要把后台服务设置为前台服务。

并且修改service启动函数。

Intent intent = new Intent(getApplicationContext(), PlayerMusicService.class);
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
    startForegroundService(intent);
} else {
    startService(intent);
}

在service的onCreate中加入

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
    Notification noti = new Notification();
    noti.flags = Notification.FLAG_NO_CLEAR | Notification.FLAG_ONGOING_EVENT;
    startForeground(1, noti);
}

有部分人说有时候还是会报错，可以在onStart 中再加入一遍startForeground。（没有遇到不知道真伪）

如需要设置Notification的其他属性可以参考如下：

Intent intent;
//点击通知栏消息跳转页
intent = new Intent(context, TargetDetailsActivity.class);

 NotificationManager manager =
                (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);

        // Intent para disparar o broadcast
        PendingIntent p = PendingIntent.getActivity(context, type, intent, PendingIntent.FLAG_UPDATE_CURRENT);

        // Cria a notification
        NotificationCompat.Builder builder = new NotificationCompat.Builder(context)
                .setContentIntent(p)
                .setContentTitle(title)
                .setContentText(txt)
                .setSmallIcon(R.drawable.ic_notifications_black_24dp)
                .setVisibility(Notification.VISIBILITY_PUBLIC)
                .setPriority(NotificationCompat.PRIORITY_MAX)
                .setAutoCancel(true)
                .setSound(Uri.parse(""))//设置空的声音和震动，否则华为手机不显示悬浮通知
//                .setDefaults(NotificationCompat.DEFAULT_ALL)//通知栏提示音、震动、闪灯等都设置为默认
                .setVibrate(new long[]{0});
        // Dispara a notification
        Notification n = builder.build();
        manager.notify(type, n);