Programmers day Android app in Kotlin

In view of the fact that today we celebrate Programmer Day, I decided to write a simple app for this event in Android Platform using Kotlin.

I will skip basics of creating an Android Project in IntelliJ IDEA. For this purpose I refer you to official Getting started with Android and Kotlin.

Just remember to make sure that in build.gradle file you have same version as in the plugin. If it is not same you will receive error: “Some Kotlin libraries attached to this project have unsupported format.Please update the libraries or the plugin”.

Here is a MainActivity:

package com.pawegio.kotlinsample.app

import android.support.v7.app.ActionBarActivity
import android.os.Bundle
import java.util.Calendar
import java.util.Date
import android.widget.TextView

public class MainActivity() : ActionBarActivity() {

    /**
     * type your name below
     */
    val YOUR_NAME = "Paweł"

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

        val textView = findViewById(R.id.textView) as TextView
        val todayView = findViewById(R.id.todayView) as TextView

        val cal = Calendar.getInstance() as Calendar
        val currDate = cal.getTime() as Date;
        val progDate = getProgrammerDayDate()

        if (isProgrammerDayToday(currDate, progDate)) {
            textView.setText("Happy Programmers Day $YOUR_NAME !!")
        } else {
            when (getDiff(currDate, progDate)) {
                in -100..-8 -> textView.setText("Programmers Day arrives soon.")
                in -7..-1 -> textView.setText("Programmers Day is so close...")
                else -> textView.setText("There is a long time till the next Programmers Day.")
            }
        }

        todayView.setText(getTodayText(cal))
    }

    fun getProgrammerDayDate(): Date {
        var cal = Calendar.getInstance() as Calendar
        cal.set(Calendar.DAY_OF_MONTH, 13)
        cal.set(Calendar.MONTH, Calendar.SEPTEMBER)
        return cal.getTime() as Date
    }

    fun isProgrammerDayToday(currDate: Date, progDate: Date) = currDate.compareTo(progDate) == 0

    fun getDiff(date: Date, progDate: Date) = date.compareTo(progDate)

    fun getTodayText(cal: Calendar): String {
        val dayOfYear = cal.get(Calendar.DAY_OF_YEAR) - 1
        val binaryDay = Integer.toBinaryString(dayOfYear)
        return "Today is:\n$binaryDay"
    }
}

package com.pawegio.kotlinsample.app

import android.support.v7.app.ActionBarActivity

import android.os.Bundle

import java.util.Calendar

import java.util.Date

import android.widget.TextView

public class MainActivity() : ActionBarActivity() {

/**

* type your name below

val YOUR_NAME = "Paweł"

override fun onCreate(savedInstanceState: Bundle?) {

super.onCreate(savedInstanceState)

setContentView(R.layout.activity_main)

val textView = findViewById(R.id.textView) as TextView

val todayView = findViewById(R.id.todayView) as TextView

val cal = Calendar.getInstance() as Calendar

val currDate = cal.getTime() as Date;

val progDate = getProgrammerDayDate()

if (isProgrammerDayToday(currDate, progDate)) {

textView.setText("Happy Programmers Day $YOUR_NAME !!")

} else {

when (getDiff(currDate, progDate)) {

in -100..-8 -> textView.setText("Programmers Day arrives soon.")

in -7..-1 -> textView.setText("Programmers Day is so close...")

else -> textView.setText("There is a long time till the next Programmers Day.")

}

todayView.setText(getTodayText(cal))

}

fun getProgrammerDayDate(): Date {

var cal = Calendar.getInstance() as Calendar

cal.set(Calendar.DAY_OF_MONTH, 13)

cal.set(Calendar.MONTH, Calendar.SEPTEMBER)

return cal.getTime() as Date

}

fun isProgrammerDayToday(currDate: Date, progDate: Date) = currDate.compareTo(progDate) == 0

fun getDiff(date: Date, progDate: Date) = date.compareTo(progDate)

fun getTodayText(cal: Calendar): String {

val dayOfYear = cal.get(Calendar.DAY_OF_YEAR) - 1

val binaryDay = Integer.toBinaryString(dayOfYear)

return "Today is:\n$binaryDay"

}

and layout:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:orientation="vertical"
    tools:context="com.pawegio.kotlinsample.app.MainActivity">

    <TextView
        android:id="@+id/textView"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1"
        android:gravity="center"
        android:textSize="30sp" />

    <TextView
        android:id="@+id/todayView"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1"
        android:gravity="center"
        android:textStyle="bold"
        android:textSize="30sp" />

</LinearLayout>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

xmlns:tools="http://schemas.android.com/tools"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:paddingLeft="@dimen/activity_horizontal_margin"

android:paddingRight="@dimen/activity_horizontal_margin"

android:paddingTop="@dimen/activity_vertical_margin"

android:paddingBottom="@dimen/activity_vertical_margin"

android:orientation="vertical"

tools:context="com.pawegio.kotlinsample.app.MainActivity">

<TextView

android:id="@+id/textView"

android:layout_width="match_parent"

android:layout_height="0dp"

android:layout_weight="1"

android:gravity="center"

android:textSize="30sp" />

<TextView

android:id="@+id/todayView"

android:layout_width="match_parent"

android:layout_height="0dp"

android:layout_weight="1"

android:gravity="center"

android:textStyle="bold"

android:textSize="30sp" />

</LinearLayout>

Hope you enjoy your day! 🙂

I attach a screenshot: