Android Common Utility Functions using Kotlin Code Examples

This article covers basic Android utility functions using Kotlin programming language.

Following Android Kotlin Utility functions are covered in this article:

• Check if internet connection is available Kotlin Android code example.
• Hide soft keyboard Kotlin Android code example.
• Put data in shared preferences Kotlin Android code example.
• Get data from shared preference in Android using Kotlin code.
• Clear shared preferences.
• Display Notification in Android using Kotlin code.
• Show alert dialog box in Android using Kotlin code.

package com.developine.kotlinandroidutils

import android.support.v7.app.AppCompatActivity
import android.os.Bundle
import android.view.Menu
import android.app.AlertDialog
import android.app.NotificationManager
import android.content.Context
import android.view.WindowManager
import android.net.ConnectivityManager
import android.provider.Settings
import android.support.v4.app.NotificationCompat
import android.telephony.TelephonyManager
import android.content.DialogInterface
import android.os.Build


class MainActivity : AppCompatActivity() {


    override fun onCreateOptionsMenu(menu: Menu?): Boolean {
        return super.onCreateOptionsMenu(menu)
    }


    override fun onDestroy() {
        super.onDestroy()
    }


    override fun onPause() {
        super.onPause()
    }


    override fun onResume() {
        super.onResume()
    }

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

    }

    // HIDE SOFT KEYBOARD ANDROID KOTLIN CODE
    fun hideSoftKeyboard() {

        getWindow().setSoftInputMode(
                WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_HIDDEN
        )
    }

    // CHECK IF NETWORK CONNECTION AVAILABLE ANDROID KOTLIN CODE
    fun isNetworkConnected(): Boolean {
        /*
        you will also need to add this permission in Manifest.
        <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
        */

        val connectivityManager = getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager
        val activeNetworkInfo = connectivityManager.activeNetworkInfo
        return activeNetworkInfo != null && activeNetworkInfo.isConnected
        return true
    }


    // SAVE DATA IN SHARED PREFRENCES ANDROID KOTLIN CODE
    fun putPrefrences(key: String, value: String) {

        val sharedPref = this?.getPreferences(Context.MODE_PRIVATE) ?: return
        with(sharedPref.edit()) {
            putString(key, value)
            commit()
        }
    }

    // READ DATA FROM SHARED PREFRENCES ANDROID KOTLIN CODE
    fun getPrefrences(key: String): String {

        val sharedPref = this?.getPreferences(Context.MODE_PRIVATE) ?: return
        val defaultValue = "no record found"
        val highScore = sharedPref.getString(key, defaultValue)

        return highScore
    }


    // CLEAR APPLICATION SHARED PREFRENCES ANDROID KOTLIN CODE
    fun clearPrefrences() {

        val sharedPref = this?.getPreferences(Context.MODE_PRIVATE) ?: return
        sharedPref.edit().clear().commit()
    }

    // CREATE NOTIFICATION ANDROID KOTLIN CODE
    fun displayNotification() {

        val mBuilder = NotificationCompat.Builder(this, "")
                .setSmallIcon(R.drawable.notification_icon)
                .setContentTitle("Notification title")
                .setContentText("Notification Content")
                .setPriority(NotificationCompat.PRIORITY_DEFAULT)

        val mNotificationManager =
                getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
        mNotificationManager.notify(1, mBuilder.build())
    }

    // GET DEVICE UNIQUE ID ANDROID KOTLIN CODE
    fun getDeviceUniqueID() {

        var androidID = Settings.Secure.getString(this.contentResolver, Settings.Secure.ANDROID_ID)
    }

    // GET DEVICE IMEI NUMBER ANDROID KOTLIN CODE
    fun getDeviceIMEI() {

        /*
        * You also need to add below permission in Manifest file.
        * <uses-permission android:name="android.permission.READ_PHONE_STATE"/>
        * */

        val telephonyManager = getSystemService(Context.TELEPHONY_SERVICE) as TelephonyManager
        telephonyManager.deviceId

    }

    // SHOW ALERT DIALOG ANDROID KOTLIN CODE
    fun showAlertDialog() {

        val builder: AlertDialog.Builder
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            builder = AlertDialog.Builder(this, android.R.style.Theme_Material_Dialog_Alert)
        } else {
            builder = AlertDialog.Builder(this)
        }
        builder.setTitle("Delete entry")
                .setMessage("Are you sure you want to delete this entry?")
                .setPositiveButton(android.R.string.yes, DialogInterface.OnClickListener { dialog, which ->
                    // continue with delete
                })
                .setNegativeButton(android.R.string.no, DialogInterface.OnClickListener { dialog, which ->
                    // do nothing
                })
                .setIcon(android.R.drawable.ic_dialog_alert)
                .show()
    }
}

Suggested Reading:

• Kotlin Idioms Tutorial
• Classes Objects Modifiers and Interfaces in Kotlin Tutorial
• Develop Android Photo Gallery app using Kotlin