Android 通知未显示

Question

测试通知未显示。 使用 Android 工作室和 Kotlin。

class MainActivity : AppCompatActivity() {
    companion object {
        const val NOTIFICATION_ID = 101
        const val CHANNEL_ID = "channelID"
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        val button : Button = findViewById(R.id.button_notification)
        button.setOnClickListener {
            val builder = NotificationCompat.Builder(this, CHANNEL_ID)
                .setSmallIcon(R.mipmap.ic_launcher)
                .setContentTitle("Notification")
                .setContentText("Go ahead")
                .setPriority(Notification.PRIORITY_HIGH)
                .setAutoCancel(true)

            val notificationManager = NotificationManagerCompat.from(this)
            notificationManager.notify(NOTIFICATION_ID, builder.build())
        }

    }
}

build.gradle（模块级别）

....
dependencies {

    implementation 'androidx.core:core:1.9.0'
    implementation 'androidx.core:core-ktx:1.7.0'
    implementation 'androidx.appcompat:appcompat:1.6.0'
    implementation 'com.google.android.material:material:1.7.0'
    implementation 'androidx.constraintlayout:constraintlayout:2.1.4'
    testImplementation 'junit:junit:4.13.2'
    androidTestImplementation 'androidx.test.ext:junit:1.1.5'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.5.1'
}

当运行应用程序并按下按钮时 - 没有任何反应，没有任何通知。

在模块级别 build.gradle 中添加了implementation 'androidx.core:core:1.9.0'

Answer 1

从 Android 8.0 开始，你需要创建一个NotificationChannel才能真正从你的 App 发布一个 Notification。 更多细节你可以参考这个。

因为您必须在 Android 8.0 及更高版本上发布任何通知之前创建通知通道，所以您应该在应用启动后立即执行此代码。 重复调用此方法是安全的，因为创建现有通知通道不会执行任何操作。

所以，在创建NotificationChannel之前需要添加一个function来创建NotificationChannel：

class MainActivity : Activity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        findViewById<Button>(R.id.btnNotification).setOnClickListener {
            createNotificationChannel()
            
            val builder = NotificationCompat.Builder(this, CHANNEL_ID)
                    .setSmallIcon(R.mipmap.ic_launcher)
                    .setContentTitle("Notification from Test")
                    .setContentText("Test Notification Message received!")
                    .setPriority(NotificationCompat.PRIORITY_DEFAULT)
                    .setAutoCancel(true)

            val notificationManager = getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager // NotificationManagerCompat.from(this)
            notificationManager.notify(NOTIFICATION_ID, builder.build())
        }
    }

    private fun createNotificationChannel() {
        // Create the NotificationChannel, but only on API 26+ because
        // the NotificationChannel class is new and not in the support library
        val name = "TestChannel"
        val descriptionText = "TestDescription"
        val importance = NotificationManager.IMPORTANCE_DEFAULT
        val channel = NotificationChannel(CHANNEL_ID, name, importance)
        channel.description = descriptionText
        // Register the channel with the system
        val notificationManager: NotificationManager =
            getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
        notificationManager.createNotificationChannel(channel)
    }

    companion object {
        const val NOTIFICATION_ID = 101
        const val CHANNEL_ID = "channelID"
    }
}