07 - Android Notifications

Notifications

Status bar

Notifications

Drawer

Notifications

Lock screen

Notifications

Heads-up (5.0+)

Notifications

App icon badge
Wear OS

Design

Material Design guide

http://developer.android.com/training/material/index.html

Notifications design guide

http://developer.android.com/design/patterns/notifications.html

Android Wear! maybe its coming back?

Oppo, Xiaomi Mi

Notifications

Standard notification

Small icon - required
App name – by system
Time stamp – by system – or setWhen() or setShowWhen(false)
Large icon – optional, only for contact photos
Title – optional, setContentTitle()
Text – optional, setContentText()
Actions – add buttons, open app when notification is tapped

Notifications

Changes over versions

API 21 (5.0) – Do not disturb mode
API 24 (7.0) – Notification grouping, Direct text input from notification
API 26 (8.0) - Notification channels are mandatory
- Better control by user (alarms, visibility, etc.)
- Max 1 notification sound per 1 second per 1 app
Notification is required for foreground service – long lived service in background and noticeable to user – ala media player or gps app.

Creating a Notification

Create the channel and set the importance – if on 8.0+
Specify the UI information and actions for a notification in a NotificationCompat.Builder object
Build the notification object
Pass the Notification object to the system by calling NotificationManager.notify()
Create channel, call it OnCreate

private fun createNotificationChannel() {
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
        val channel = NotificationChannel(
            "channel",
            "Default channel",
            NotificationManager.IMPORTANCE_DEFAULT
        );
        channel.description = "Default channel for Channel Demo"
        var notificationManager: NotificationManager =
            getSystemService(Context.NOTIFICATION_SERVICE) 
                as NotificationManager;
        notificationManager.createNotificationChannel(channel)
    }
}

Required notification contents
- Small icon – setSmallIcon()
Optional contents
- Title – setContentTitle()
- Detail text – setContentText()
- Actions, priority, sound, led flashing, time, vibrate, ticker, …
- http://developer.android.com/reference/android/support/v4/app/NotificationCompat.Builder.html

    fun button0OnClick(view: View) {
        var builder = NotificationCompat.Builder(this, "channel")
            .setSmallIcon(android.R.drawable.sym_def_app_icon)
            .setContentTitle("Title is here")
            .setContentText("Content text is this!")
            .setPriority(NotificationCompat.PRIORITY_DEFAULT)

        NotificationManagerCompat.from(this).notify(0, builder.build())
    }

Notification action

You should add at least one action – to navigate into your app/activity
You can also add Buttons for additional actions
Action is defined by PendingIntent, containing an Intent
Navigation stack - what should happen in your activity, when back is pressed (should it navigate to the home screen or to some other activity)

    fun button1OnClick(view: View) {
        val intent = Intent(this, MainActivity::class.java)
        val pendingIntent = PendingIntent
            .getActivity(this,0, intent, PendingIntent.FLAG_IMMUTABLE)


        var builder = NotificationCompat.Builder(this, "channel")
            .setSmallIcon(android.R.drawable.sym_contact_card)
            .setContentTitle("Title is here")
            .setContentText("Content text is this!")
            //.setContentInfo("info is here")
            .setPriority(NotificationCompat.PRIORITY_DEFAULT)
            .setVisibility(NotificationCompat.VISIBILITY_PUBLIC)
            .setContentIntent(pendingIntent)
            .setAutoCancel(true)


        NotificationManagerCompat.from(this).notify(0, builder.build())

    }

Expanded layout

Expanded layout – action buttons depend on it (android 4.1+)

Notifications

Update and remove

Update notification

Issue notification with a notification ID by calling NotificationManager.notify()
Update or create a NotificationCompat.Builder object
build a Notification object from it, and issue the Notification with the same ID.
If the previous notification is still visible, the system updates it.
If the previous notification has been dismissed, a new notification is created.

Remove notification

notificatoinManager.cancel(id)
notificatoinManager.cancelAll()
Or use setTimeoutAfter() for timed removal

Regular activity

Start an activity, that is part of normal workflow of your app

ActivityA is your main activity
ActivityB is started from notification
Backstack: Home <- ActivityA <- ActivityB

Special activity

Start an activity, that is an extension of your notification

No backstack needed, touching back takes you directly to Home screen

Regular notification

Define hierarchy in manifest

<activity
    android:name=".MainActivity"
    android:label="@string/app_name" >
    <intent-filter>
        <action android:name="android.intent.action.MAIN" />
        <category android:name="android.intent.category.LAUNCHER" />
    </intent-filter>
</activity>
<activity
    android:name=".ResultActivity"
    android:parentActivityName=".MainActivity">
    <meta-data
        android:name="android.support.PARENT_ACTIVITY"
        android:value=".MainActivity"/>
</activity>

Create Intent
Create stack builder – TaskStackBuilder.Create()
Get and use pendingIntent

// Create an Intent for the activity you want to start
val resultIntent = Intent(this, ResultActivity::class.java)

// Create the TaskStackBuilder
val resultPendingIntent: PendingIntent? = TaskStackBuilder.create(this).run {
    // Add the intent, which inflates the back stack
    addNextIntentWithParentStack(resultIntent)
    // Get the PendingIntent containing the entire back stack
    getPendingIntent(0, PendingIntent.FLAG_IMMUTABLE)
}

Special notification

Manifest

<activity
    android:name=".ResultActivity"
    android:launchMode="singleTask"
    android:taskAffinity=""
    android:excludeFromRecents="true">
</activity>

Build and issue the notification

Create Intent for Activity
setFlags() with the flags FLAG_ACTIVITY_NEW_TASK and FLAG_ACTIVITY_CLEAR_TASK
Create a PendingIntent from the Intent by calling getActivity()

fun onClickButtonNotify(view: View) {
    // create intent
    val intent = Intent(this, MainActivity::class.java)
    val pendingIntent = PendingIntent.getActivity(this, 0, intent, 0)

    // construct and show notification
    var builder = NotificationCompat.Builder(this, "channel")
        .setSmallIcon(R.drawable.baseline_android_24)
        .setContentTitle("Notification title")
        .setContentText("Notification body text")
        .setPriority(NotificationCompat.PRIORITY_DEFAULT)
        .setContentIntent(pendingIntent)
        // should notification be removed, when user clicks on it
        .setAutoCancel(true)
        .setVisibility(NotificationCompat.VISIBILITY_PUBLIC)

    NotificationManagerCompat.from(this).notify(0, builder.build())
}

Communication from notification

Action, without starting whole new Activity

Use broadcasts, ofcourse!
= PendingIntent.getBroadcast()
And regular (not local) BroadcastReceiver in your app/activity

    var broadcastReceiverIntentFilter = IntentFilter()
    private val broadcastReceiver = CustomBrodcastReceiver()


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

        createNotificationChannel()

        broadcastReceiverIntentFilter.addAction("ee.itcollege.akaver.cp")

    }


    fun button3OnClick(view: View) {
        val notifyView = RemoteViews(packageName, R.layout.notification)

        val intentLaunch = Intent(this, MainActivity::class.java)
        val pendingIntentLaunch = PendingIntent.getActivity(this,0, intentLaunch,0)

        val intent = Intent("ee.itcollege.akaver.cp")
        val pendingIntent = PendingIntent.getBroadcast(this, 0, intent,0)

        notifyView.setOnClickPendingIntent(R.id.imageButtonCheckpoint, pendingIntent);
        notifyView.setTextViewText(R.id.textViewCounter, "some text")

        var builder = NotificationCompat.Builder(this, "channel")
            .setSmallIcon(android.R.drawable.sym_contact_card)
            .setPriority(NotificationCompat.PRIORITY_DEFAULT)
            .setVisibility(NotificationCompat.VISIBILITY_PUBLIC)
            .setContentIntent(pendingIntentLaunch)
            .setStyle(NotificationCompat.DecoratedCustomViewStyle())
            .setCustomContentView(notifyview)
            .setContent(notifyview)

        NotificationManagerCompat.from(this).notify(0, builder.build())
    }


    private inner class CustomBrodcastReceiver: BroadcastReceiver() {
        override fun onReceive(context: Context?, intent: Intent?) {
            Log.d("receiver", "onReceive")
        }

    }

    override fun onResume() {
        super.onResume()
        this.registerReceiver(broadcastReceiver,broadcastReceiverIntentFilter )
    }

    override fun onPause() {
        super.onPause()
        this.unregisterReceiver(broadcastReceiver)
    }

Custom layout

Use RemoteViews

Define layout in usual way (xml), max height 64dp (expanded 256dp)

val intentCp = Intent("ee.itcollege.akaver.cp")
val pendingIntentCp = PendingIntent.getBroadcast(this, 0, intentCp, 0)
val notifyview = RemoteViews(packageName, R.layout.notification)
notifyview.setOnClickPendingIntent(R.id.imageButtonCheckpoint, pendingIntentCp)

// construct and show notification
var builder = NotificationCompat.Builder(this, "channel")
    .setSmallIcon(R.drawable.baseline_my_location_black_24)
    .setPriority(NotificationCompat.PRIORITY_DEFAULT)
    .setVisibility(NotificationCompat.VISIBILITY_PUBLIC)
    .setStyle(NotificationCompat.DecoratedCustomViewStyle())
    .setCustomContentView(notifyview)
    .setContent(notifyview)

NotificationManagerCompat.from(this).notify(0, builder.build())

RemoteViews

Supports only these layouts:

AdapterViewFlipper
FrameLayout
GridLayout
GridView
LinearLayout
ListView
RelativeLayout
StackView
ViewFlipper

And only these widgets:

AnalogClock
Button
Chronometer
ImageButton
ImageView
ProgressBar
TextClock
TextView

Descendants of these classes are also not supported.

NB!
Don’t set onClick on shared views (views used both in regular layouts and notifications)

RemoteViews - update content

Update texts
- remoteView.setTextViewText(R.id.text, "text")
Set intents to button clicks
- remoteView.setOnClickPendingIntent(R.id.button, pendingIntent)
Since this is pending intent, you need to use proper broadcastReceiver to receive it
- registerReceiver(mBroadcastReceiver, intentFilter)
- unregisterReceiver(mBroadcastReceiver)

Custom Layout

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:internal="http://schemas.android.com/apk/prv/res/android"
    android:id="@+id/status_bar_latest_event_content"
    android:layout_width="match_parent"
    android:layout_height="64dp"
    internal:layout_maxHeight="64dp"
    internal:layout_minHeight="64dp" >

    <ImageView
        android:id="@+id/notification_icon_iv"
        android:layout_width="64dp"
        android:layout_height="64dp"
        android:padding="10dp"
        android:layout_alignParentLeft="true"
        android:scaleType="center"
        android:src="@drawable/notification_icon"
        android:background="#3333B5E5" />

    <ImageButton
        android:id="@+id/notification_closebtn_ib"
        android:layout_width="40dp"
        android:layout_height="40dp"
        android:layout_alignParentRight="true"
        android:layout_centerVertical="true"
        android:scaleType="centerInside"
        android:src="@drawable/notification_exitbtn"
        android:background="@drawable/notification_imagebtn_bg"/>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="fill_vertical"
        android:gravity="top"
        android:minHeight="64dp"
        android:layout_toRightOf="@id/notification_icon_iv"
        android:layout_toLeftOf="@id/notification_closebtn_ib"
        android:orientation="vertical"
        android:paddingBottom="2dp"
        android:paddingEnd="8dp"
        android:paddingTop="2dp" >

        <TextView
            android:id="@+id/notification_title_tv"
            style="@android:style/TextAppearance.StatusBar.EventContent.Title"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginLeft="8dp"
            android:ellipsize="marquee"
            android:paddingTop="6dp"
            android:singleLine="true"
            android:text="JMols Service" />

        <TextView
            android:id="@+id/notification_contenttext_tv"
            style="@android:style/TextAppearance.StatusBar.EventContent"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginLeft="8dp"
            android:ellipsize="marquee"
            android:singleLine="true"
            android:text="Service running in the background" />

    </LinearLayout>

</RelativeLayout>

Notifcation Background

<selector xmlns:android="http://schemas.android.com/apk/res/android"
    android:exitFadeDuration="@android:integer/config_mediumAnimTime">

    <item android:state_pressed="true"  android:drawable="@drawable/notification_bg_normal_pressed" />
    <item android:state_pressed="false" android:drawable="@drawable/notification_bg_normal" />
</selector>

Imagebutton background

<selector xmlns:android="http://schemas.android.com/apk/res/android"
    android:exitFadeDuration="@android:integer/config_mediumAnimTime">

    <item android:state_pressed="true"  android:drawable="@drawable/notification_imagebtn_bg_normal_pressed" />
    <item android:state_pressed="false" android:drawable="@drawable/notification_imagebtn_bg_normal" />
</selector>

Foreground service and notification

         // construct and show notification
        var builder = NotificationCompat.Builder(applicationContext, C.NOTIFICATION_CHANNEL)
            .setSmallIcon(R.drawable.baseline_gps_fixed_24)
            .setPriority(NotificationCompat.PRIORITY_LOW)
            .setOngoing(true)
            .setVisibility(NotificationCompat.VISIBILITY_PUBLIC)

        builder.setContent(notifyview)

        // Super important, start as foreground service - ie android considers this as an active app. Need visual reminder - notification.
        // must be called within 5 secs after service starts.
        startForeground(C.NOTIFICATION_ID, builder.build())

Notifications​

Design​

Standard notification​

Changes over versions​

Creating a Notification​

Notification action​

Expanded layout​

Update and remove​

Navigation​

Regular activity​

Special activity​

Regular notification​

Special notification​

Communication from notification​

Custom layout​

RemoteViews​

RemoteViews - update content​

Custom Layout​

Foreground service and notification​

Notifications

Design

Standard notification

Changes over versions

Creating a Notification

Notification action

Expanded layout

Update and remove

Navigation

Regular activity

Special activity

Regular notification

Special notification

Communication from notification

Custom layout

RemoteViews

RemoteViews - update content

Custom Layout

Foreground service and notification