Android Progress Bar Example using Kotlin

1. Creating New Project in Kotlin

• Open Android Studio.
• Go to File => New => New Project.Give Name To your application. Then, check Include Kotlin Support and click next button.
• Select minimum SDK you need. However, we have selected 21 as minimum SDK. Then, click next button.
• Then, select Empty Activity => click next => click finish.

2.  Here we take Progress Bar (Horizontal) and Button.As in below xml layout.

main_activity.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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="com.dharmendra.progressbar.MainActivity">


    <ProgressBar
        android:id="@+id/progressBar"
        style="?android:attr/progressBarStyleHorizontal"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="85dp" />

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/progressBar"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="42dp"
        android:text="Button" />


</RelativeLayout>

3.MainActivity.kt

package com.dharmendra.progressbar

import android.os.Bundle
import android.support.v7.app.AppCompatActivity
import android.util.Log
import android.widget.Button
import android.widget.ProgressBar

class MainActivity : AppCompatActivity() {

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

        //Find  view By Id for ProgressBar,Button

        val progressBar = findViewById<ProgressBar>(R.id.progressBar) as ProgressBar
        val btn = findViewById<Button>(R.id.button) as Button

        //On Click for Button
        btn.setOnClickListener {


            //Set button Clickable false to stop multiple Clicks at a time
            btn.isClickable = false

            //Here We Create one Thread to change Status of Progress bar
            var status = 0   //Initial status of Progress Bar

            Thread(Runnable {

                while (status < 100) {

                    status += 1


                    //if error Occures than it will habdle in try-catch block.

                    try {

                        Thread.sleep(30)
                        progressBar.setProgress(status)
                    } catch (e: Exception) {

                        Log.e("Error", e.message)
                    }


                }


                //Set Button Clickable true after Progress Complete
                btn.isClickable = true

            }).start()

        }


    }
}

Output:

Android Switch Widget Example Using Kotlin

1. Creating New Project in Kotlin

• Open Android Studio.
• Go to File => New => New Project.Give Name To your application. Then, check Include Kotlin Support and click next button.
• Select minimum SDK you need. However, we have selected 21 as minimum SDK. Then, click next button.
• Then, select Empty Activity => click next => click finish.

2. Here We Take Switch in our Layout . As in below xml layout.

main_activity.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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="com.dharmendra.aswitch.MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentStart="true"
        android:layout_alignParentTop="true"
        android:layout_marginStart="50dp"
        android:layout_marginTop="139dp"
        android:text="Switch :"
        android:textSize="20dp"
        android:textColor="@android:color/black"
        android:textStyle="bold"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        android:id="@+id/textView" />

    <Switch
        android:id="@+id/sw"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignTop="@+id/textView"
        android:layout_centerHorizontal="true"/>

</RelativeLayout>

3. MainActivity.kt

package com.dharmendra.aswitch

import android.support.v7.app.AppCompatActivity
import android.os.Bundle
import android.widget.Switch
import android.widget.Toast

class MainActivity : AppCompatActivity() {

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

        //Find View By Id for Switch

        val s=findViewById<Switch>(R.id.sw) as Switch

        //Onclik For Switch

        s.setOnClickListener {

            //To Chek Switch is On Or Off
            if(s.isChecked){
                Toast.makeText(this@MainActivity,"Switch is On",Toast.LENGTH_LONG).show()
            }

            else{
                Toast.makeText(this@MainActivity,"Switch is Off",Toast.LENGTH_LONG).show()
            }
        }
    }
}

Output:

Android Spinner/Drop Down Menu Example Using Kotlin

1. Creating New Project in Kotlin

• Open Android Studio.
• Go to File => New => New Project.Give Name To your application. Then, check Include Kotlin Support and click next button.
• Select minimum SDK you need. However, we have selected 21 as minimum SDK. Then, click next button.
• Then, select Empty Activity => click next => click finish.

2. Here We Take Spinner in our Layout . As in below xml layout.

main_activity.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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="com.dharmendra.spinner.MainActivity">

    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentStart="true"
        android:layout_alignParentTop="true"
        android:layout_marginTop="73dp"
        android:gravity="center"
        android:textSize="20dp"
        android:textStyle="bold"
        android:textColor="@android:color/holo_blue_dark"
        android:text="Select Country"
        android:id="@+id/textView" />

    <Spinner
        android:id="@+id/country"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentStart="true"
        android:layout_below="@+id/textView"
        android:layout_marginStart="16dp"
        android:layout_marginTop="26dp" />


</RelativeLayout>

3. MainActivity.kt

package com.dharmendra.spinner

import android.support.v7.app.AppCompatActivity
import android.os.Bundle
import android.view.View
import android.widget.*

class MainActivity : AppCompatActivity() {

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

        //Find View by id for Spinner and Button


        val spinner=findViewById<Spinner>(R.id.country) as Spinner

        //Create An Array which Contain Country name

        val country= arrayOf("India","United States","Canada","Russia","Brazil")

        //Set Array in Adapter

        val adapter=ArrayAdapter(this@MainActivity,android.R.layout.simple_spinner_dropdown_item,country)

        spinner.adapter=adapter


      spinner.onItemSelectedListener=object :AdapterView.OnItemSelectedListener{
          override fun onNothingSelected(p0: AdapterView<*>?) {
              TODO("not implemented") //To change body of created functions use File | Settings | File Templates.
          }

          override fun onItemSelected(p0: AdapterView<*>?, p1: View?, p2: Int, p3: Long) {

              Toast.makeText(this@MainActivity,"You have Selected "+country[p2],Toast.LENGTH_LONG).show()

          }

      }



    }
}

Output: