我就是想做個筆記而已，給自己看看而已

第一步：
面向Android 9（API級別28）或更高版本并使用前臺服務(wù)的應(yīng)用必須請求 FOREGROUND_SERVICE 權(quán)限

so先來個權(quán)限
<uses-permission android:name="android.permission.FOREGROUND_SERVICE"/>

然后啟動一個前臺服務(wù)

val pendingIntent: PendingIntent =
Intent(this, ExampleActivity::class.java).let { notificationIntent ->
PendingIntent.getActivity(this, 0, notificationIntent, 0)
}

val notification: Notification = Notification.Builder(this, CHANNEL_DEFAULT_IMPORTANCE)
.setContentTitle(getText(R.string.notification_title))
.setContentText(getText(R.string.notification_message))
.setSmallIcon(R.drawable.icon)
.setContentIntent(pendingIntent)
.setTicker(getText(R.string.ticker_text))
.build()

// Notification ID cannot be 0.
startForeground(ONGOING_NOTIFICATION_ID, notification)

最后你發(fā)現(xiàn)，死活就是tm的沒開起來，還崩潰了，哈哈啊啊啊哈哈

然后再看看，發(fā)現(xiàn)還需要tn的什么通道，先不管了，先上代碼：

 val notificationManager: NotificationManager =
        getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
        val name = getString(R.string.app_name)
        val descriptionText = getString(R.string.app_name)
        val importance = NotificationManager.IMPORTANCE_DEFAULT
        val channel = NotificationChannel("1232155654686578343", name, importance).apply {
            description = descriptionText
        }
        // Register the channel with the system

        notificationManager.createNotificationChannel(channel)
    }

就是這個小混蛋創(chuàng)建了什么通道
然后調(diào)用
notificationManager.notify(1, notification)
好了差不多了
完整代碼就是這樣的：
@RequiresApi(Build.VERSION_CODES.O)
fun createNotificationChannel() {
val notificationManager: NotificationManager =
getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
val name = getString(R.string.app_name)
val descriptionText = getString(R.string.app_name)
val importance = NotificationManager.IMPORTANCE_DEFAULT
val channel = NotificationChannel("1232155654686578343", name, importance).apply {
description = descriptionText
}
// Register the channel with the system

        notificationManager.createNotificationChannel(channel)
    }
    val pendingIntent: PendingIntent =
        Intent(this, MainActivity::class.java).let { notificationIntent ->
            PendingIntent.getActivity(this, 0, notificationIntent, 0)
        }

    val notification: Notification = Notification.Builder(baseContext, "1232155654686578343")
        .setContentTitle(getText(R.string.app_name))
        .setContentText(getText(R.string.app_name))
        .setSmallIcon(R.drawable.ic_back)
        .setContentIntent(pendingIntent)
        .setTicker(getText(R.string.app_name))
        .build()
    startForeground(123, notification)
    notificationManager.notify(1, notification)
}

然后發(fā)現(xiàn)你的前臺服務(wù)就這么簡單愉快的啟動起來了，至于能不能?；钗揖筒欢?，等待驗(yàn)證了
反正搞了這么多都是為了?；?/p>

注意：Notification.Builder(baseContext, "1232155654686578343")和NotificationChannel("1232155654686578343", name, importance)
這兩個是要一樣的

其實(shí)不懂的看官網(wǎng)，比網(wǎng)上哪些亂七八糟的靠譜多了，百度百度 .... 擺渡擺渡..... 全是一個抄一個.....