提高Service优先级

在onStartCommand()方法中开启一个通知，提高进程的优先级。注意：从Android 8.0（API级别26）开始，所有通知必须要分配一个渠道，对于每个渠道，可以单独设置视觉和听觉行为。然后用户可以在设置中修改这些设置，根据应用程序来决定哪些通知可以显示或者隐藏。

定义一个通知工具类，兼容8.0

class NotificationUtils(context: Context) : ContextWrapper(context) {

private var manager: NotificationManager? = null
private var id: String = context.packageName + "51"
private var name: String = context.packageName
private var context: Context = context
private var channel: NotificationChannel? = null

companion object {
@SuppressLint("StaticFieldLeak")
private var notificationUtils: NotificationUtils? = null

fun createNotification(context: Context, title: String, content: String, icon: Int, intent: Intent): Notification? {
if (notificationUtils == null) {
notificationUtils = NotificationUtils(context)
}
var notification: Notification? = null
notification = if (Build.VERSION.SDK_INT >= 26) {
notificationUtils?.createNotificationChannel()
notificationUtils?.getChannelNotification(title, content, icon, intent)?.build()
} else {
notificationUtils?.getNotification_25(title, content, icon, intent)?.build()
}
return notification
}
}

@RequiresApi(api = Build.VERSION_CODES.O)
fun createNotificationChannel() {
if (channel == null) {
channel = NotificationChannel(id, name, NotificationManager.IMPORTANCE_MIN)
channel?.enableLights(false)
channel?.enableVibration(false)
channel?.vibrationPattern = longArrayOf(0)
channel?.setSound(null, null)
getManager().createNotificationChannel(channel)
}
}

private fun getManager(): NotificationManager {
if (manager == null) {
manager = getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
}
return manager!!
}

@RequiresApi(api = Build.VERSION_CODES.O)
fun getChannelNotification(title: String, content: String, icon: Int, intent: Intent): Notification.Builder {
//PendingIntent.FLAG_UPDATE_CURRENT 这个类型才能传值
val pendingIntent = PendingIntent.getBroadcast(context, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT)
return Notification.Builder(context, id)
.setContentTitle(title)
.setContentText(content)
.setSmallIcon(icon)
.setAutoCancel(true)
.setContentIntent(pendingIntent)
}

fun getNotification_25(title: String, content: String, icon: Int, intent: Intent): NotificationCompat.Builder {
val pendingIntent = PendingIntent.getBroadcast(context, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT)
return NotificationCompat.Builder(context, id)
.setContentTitle(title)
.setContentText(content)
.setSmallIcon(icon)
.setAutoCancel(true)
.setVibrate(longArrayOf(0))
.setSound(null)
.setLights(0, 0, 0)
.setContentIntent(pendingIntent)
}