Kotlin AndroidX Preferenc and Settings Examples

The Preference library allows you to build interactive settings screens, without needing to handle interacting with device storage or managing the user interface.

Settings

Settings allow users to change the functionality and behavior of an application. Settings can affect background behavior, such as how often the application synchronizes data with the cloud, or they can be more wide-reaching, such as changing the contents and presentation of the user interface.

The recommended way to integrate user configurable settings into your application is to use the AndroidX Preference Library. This library manages the user interface and interacts with storage so that you define only the individual settings that the user can configure. The library comes with a Material theme that provides a consistent user experience across devices and OS versions.

How to create a Settings Screen

You can create a Settings screen in two way: via xml or via code. Here is the screen that we will build in the two ways:

(a). Via XML

<PreferenceScreen
    xmlns:app="http://schemas.android.com/apk/res-auto">

    <SwitchPreferenceCompat
        app:key="notifications"
        app:title="Enable message notifications"/>

    <Preference
        app:key="feedback"
        app:title="Send feedback"
        app:summary="Report technical issues or suggest new features"/>

</PreferenceScreen>

The above xml will give you the following:

(b). Via Code

You can also build a settings screen programmatically via code. Below are code examples:

override fun onCreatePreferences(savedInstanceState: Bundle?, rootKey: String?) {
    val context = preferenceManager.context
    val screen = preferenceManager.createPreferenceScreen(context)

    val notificationPreference = SwitchPreferenceCompat(context)
    notificationPreference.key = "notifications"
    notificationPreference.title = "Enable message notifications"

    val feedbackPreference = Preference(context)
    feedbackPreference.key = "feedback"
    feedbackPreference.title = "Send feedback"
    feedbackPreference.summary = "Report technical issues or suggest new features"

    screen.addPreference(notificationPreference)
    screen.addPreference(feedbackPreference)

    preferenceScreen = screen
}

Adding a [PreferenceCategory is similar, as shown below. Remember to add the children to the PreferenceCategory and not to the root PreferenceScreen:

override fun onCreatePreferences(savedInstanceState: Bundle?, rootKey: String?) {
    val context = preferenceManager.context
    val screen = preferenceManager.createPreferenceScreen(context)

    val notificationPreference = SwitchPreferenceCompat(context)
    notificationPreference.key = "notifications"
    notificationPreference.title = "Enable message notifications"

    val notificationCategory = PreferenceCategory(context)
    notificationCategory.key = "notifications_category"
    notificationCategory.title = "Notifications"
    screen.addPreference(notificationCategory)
    notificationCategory.addPreference(notificationPreference)

    val feedbackPreference = Preference(context)
    feedbackPreference.key = "feedback"
    feedbackPreference.title = "Send feedback"
    feedbackPreference.summary = "Report technical issues or suggest new features"

    val helpCategory = PreferenceCategory(context)
    helpCategory.key = "help"
    helpCategory.title = "Help"
    screen.addPreference(helpCategory)
    helpCategory.addPreference(feedbackPreference)

    preferenceScreen = screen
}

More Examples

Here are more examples

1. Kotlin Android PreferenceX Example

Let us look at a Android PreferenceXExample-android-master example.

This example will comprise the following files:

• MainActivity.kt
• SettingsFragment.kt
• SettingsSyncFragment.kt

Step 1: Create Project

1. Open your AndroidStudio IDE.
2. Go to File-->New-->Project to create a new project.

Step 2: Add Dependencies

In your app/build.gradle add dependencies as shown below. Include the androidx.preference:preference as a dependency:

    implementation "androidx.preference:preference:1.1.0-alpha01"

Step 3: Design Layouts

*(a). activity_main.xml

Create a file named activity_main.xml and design it as follows:

<?xml version="1.0" encoding="utf-8"?>
<androidx.coordinatorlayout.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <com.google.android.material.appbar.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:theme="@style/AppTheme.AppBarOverlay">

        <androidx.appcompat.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:background="?attr/colorPrimary"
            app:popupTheme="@style/AppTheme.PopupOverlay" />

    </com.google.android.material.appbar.AppBarLayout>

    <FrameLayout
        android:id="@+id/container"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_behavior="@string/appbar_scrolling_view_behavior" />

</androidx.coordinatorlayout.widget.CoordinatorLayout>

*(b). content_main.xml

Create a file named content_main.xml and design it as follows:

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_behavior="@string/appbar_scrolling_view_behavior"
        tools:showIn="@layout/activity_main"
        tools:context=".MainActivity">

    <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Hello World!"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintLeft_toLeftOf="parent"
            app:layout_constraintRight_toRightOf="parent"
            app:layout_constraintTop_toTopOf="parent"/>

</androidx.constraintlayout.widget.ConstraintLayout>

Step 4: Write Code

Write Code as follows:

(a). MainActivity.kt

Create a file named MainActivity.kt and implement the PreferenceFragmentCompat.OnPreferenceStartFragmentCallback interface then override the onPreferenceStartFragment function:

    override fun onPreferenceStartFragment(caller: PreferenceFragmentCompat?, pref: Preference?): Boolean = false

Here is the full code

package com.numero.preference_androidx

import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import androidx.preference.Preference
import androidx.preference.PreferenceFragmentCompat
import kotlinx.android.synthetic.main.activity_main.*

class MainActivity : AppCompatActivity(), PreferenceFragmentCompat.OnPreferenceStartFragmentCallback {

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

        supportFragmentManager.beginTransaction()
                .replace(R.id.container, SettingsFragment())
                .commit()
    }

    override fun onPreferenceStartFragment(caller: PreferenceFragmentCompat?, pref: Preference?): Boolean = false
}

(b). SettingsFragment.kt

Create a file named SettingsFragment.kt and extend the PreferenceFragmentCompat then override the onCreatePreferences as shown below:

    override fun onCreatePreferences(savedInstanceState: Bundle?, rootKey: String?) {
        setPreferencesFromResource(R.xml.settings, rootKey)
    }

Here is the full code

package com.numero.preference_androidx

import android.os.Bundle
import androidx.preference.PreferenceFragmentCompat

class SettingsFragment : PreferenceFragmentCompat() {
    override fun onCreatePreferences(savedInstanceState: Bundle?, rootKey: String?) {
        setPreferencesFromResource(R.xml.settings, rootKey)
    }
}

(c). SettingsSyncFragment.kt

Create a file named SettingsSyncFragment.kt and extend the PreferenceFragmentCompat then override the onCreatePreferences and onCreate functions as shown:

    override fun onCreatePreferences(savedInstanceState: Bundle?, rootKey: String?) {
        setPreferencesFromResource(R.xml.settings_sync, rootKey)
    }

Here is the full code

package com.numero.preference_androidx

import android.os.Bundle
import androidx.preference.Preference
import androidx.preference.PreferenceFragmentCompat
import androidx.preference.SwitchPreferenceCompat

class SettingsSyncFragment : PreferenceFragmentCompat() {
    override fun onCreatePreferences(savedInstanceState: Bundle?, rootKey: String?) {
        setPreferencesFromResource(R.xml.settings_sync, rootKey)
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        val syncSummaryProvider = Preference.SummaryProvider<SwitchPreferenceCompat> { preference ->
            if (preference.isChecked) {
                "Checked"
            } else {
                "Non checked"
            }
        }

        findPreference("enable_sync").summaryProvider = syncSummaryProvider
    }
}

Run

Simply copy the source code into your Android Project,Build and Run.

Reference

1. Download code or Browse here.
2. Follow code author.