Hide Navigation – Android Tip – 1

By | October 29, 2018

We are starting simple posts for tips in Android so that you can master android very fast in a very simple manner. Here is a simple android tip. Hide Software Navigation in Android


RNFirebase core module was not found natively on ios – Fix

By | October 28, 2018

This issue happens in react-native-firebase for a various reasons. First thing you have to do is check Firebase/Core is in your pods. Try Cleaning and rebuilding your project. Click on the target you are running in xcode and check the frameworks section in ‘General’ Tab -> Check you have linked libFirebase.a there. If not click the “+” button… Read More »


Interview Question & Answers – Migratory Birds Count – 11

By | October 23, 2018

Question You have been asked to help study the population of birds migrating across the continent. Each type of bird you are interested in will be identified by an integer value. Each time a particular kind of bird is spotted, its id number will be added to your array of sightings. You would like to be able to… Read More »


Interview Question & Answer – 10 – Divisible Sum pairs

By | October 22, 2018

Question Find the count where the number k is divisible by sum of two numbers in the array and first number index should be less than second number index. Function has the following parameter(s): n: the integer length of array ar: an array of integers k: the integer to divide the pair sum by You can download the… Read More »


Interview Question – 9

By | October 15, 2018

Question Maria plays college basketball and wants to go pro. Each season she maintains a record of her play. She tabulates the number of times she breaks her season record for most points and least points in a game. Points scored in the first game establish her record for the season, and she begins counting from there. For… Read More »


Doing Simple Navigation in Flutter – Simple Example

By | October 12, 2018

Navigation is done is Flutter using the Navigator class. Lets look at a simple example The first thing you have to register routes for difference screen is to build a Map of ‘String’ (route) and the page (Widget).   Lets say I have a utility class for the Creating Routes named routes.dart. The contents of route.dart contains the… Read More »


GridView Demo in Flutter

By | October 10, 2018

Hi Friends, Today we will see how to implement GridView in Flutter.     We are going to use this service for the data First we will create a Model for the Grid Cell No we will create view for Grid Cell Create a file named “cell.dart” and copy this into it. Service Class We have the below… Read More »


Interview Question & Answer – 9

By | October 10, 2018

Question Given a time in -hour AM/PM format, convert it to military (24-hour) time. Note: Midnight is 12:00:00AM on a 12-hour clock, and 00:00:00 on a 24-hour clock. Noon is 12:00:00PM on a 12-hour clock, and 12:00:00 on a 24-hour clock. Sample Input 07:05:45PM Sample Output 19:05:45 Solution


Interview Question & Answer – 8

By | October 8, 2018

Question You are in charge of the cake for your niece’s birthday and have decided the cake will have one candle for each year of her total age. When she blows out the candles, she’ll only be able to blow out the tallest ones. Your task is to find out how many candles she can successfully blow out.… Read More »


Doing HTTP Calls in Flutter and Parsing Data

By | October 7, 2018

Here is a simple example of doing Http calls in Flutter. In this example we will try to fetch some JSON value from the below url https://jsonplaceholder.typicode.com/posts/1 You can read more from here. Add Dependencies First you need to add the http plugin in dependencies. The latest version of http can be found here (https://pub.dartlang.org/packages/http). Example Lets look… Read More »


Flutter – Saving Data in Local using Shared Preferences

By | October 4, 2018

This simple example demonstrates saving an integer value in the local shared preferences. We will use a flutter plugin called shared_preferences for this. You can read more about the plugin from here. Add Dependency First thing is to add the package to the dependencies. Go to pubspec.yaml and add the package. Example


Interview Question & Answer – 6

By | October 4, 2018

Question Given a square matrix, calculate the absolute difference between the sums of its diagonals. For example, the square matrix is shown below: 1 2 3 4 5 6 9 8 9 Ans : | (1+5+9) – (3+5+9) | = 2. Solution


Interview Question & Answer – 5

By | October 3, 2018

Question Alice and Bob each created one problem for our company. A reviewer rates the two challenges, awarding points on a scale from to for three categories: problem clarity, originality, and difficulty. We define the rating for Alice’s challenge to be the triplet , and the rating for Bob’s challenge to be the triplet . Your task is… Read More »


Interview Question & Answer – 4

By | October 2, 2018

Question Lilah has a string, , of lowercase English letters that she repeated infinitely many times. Given an integer, , find and print the number of letter a’s in the first letters of Lilah’s infinite string. For example, if the string and , the substring we consider is , the first characters of her infinite string. There are… Read More »


Interview Question and Answer – 3

By | October 1, 2018

Question Emma is playing a new mobile game that starts with consecutively numbered clouds. Some of the clouds are thunderheads and others are cumulus. She can jump on any cumulus cloud having a number that is equal to the number of the current cloud plus or . She must avoid the thunderheads. Determine the minimum number of jumps… Read More »


Interview Question and Solution – 2

By | September 30, 2018

Gary is an avid hiker. He tracks his hikes meticulously, paying close attention to small details like topography. During his last hike he took exactly steps. For every step he took, he noted if it was an uphill, , or a downhill, step. Gary’s hikes start and end at sea level and each step up or down represents… Read More »


Simple Interview Question and Answer – 1

By | September 28, 2018

Question John works at a clothing store. He has a large pile of socks that he must pair by color for sale. Given an array of integers representing the color of each sock, determine how many pairs of socks with matching colors there are. For example, there are socks with colors . There is one pair of color… Read More »


SQlite Database Operations in Flutter

By | September 27, 2018

Watch Video Tutorial   Add Dependency SQFlite is a Flutter library for doing local Database Operations. You can download it from here. To Integrate SQFlite library in your project In your flutter project add the dependency: You can download the sample project from here. employee.dart Database Utils Here is a sample DB Utility file. DBHelper.dart Implementation Widget This… Read More »


How to do Unit Test of functions and Widgets in Flutter?

By | September 24, 2018

Lets see how we can test Flutter Apps. It would be easy if we continue from the previous example…   To test Widgets, we will use the ‘testWidgets’ function. Lets see how it will look like… The test function in MyHomePage will look like this Run Tests To run test we have to run ‘flutter test test/widget_test.dart’ in… Read More »


Start with Flutter – Build Android and iOS Apps Instantly.

By | September 23, 2018

In this course we will learn how to Start with Flutter, Google’s own cross platform solution.     So I am assuming that you have the flutter SDK and other stuff installed. if not please go to https://flutter.io and download it and setup. Android Studio If you are using Android Studio as your primary editor, then you should… Read More »


Things to Know About Mobile UX

By | August 30, 2018

Mobile user experience is not only related to design something to use on the mobile devices. It is a process that requires brainstorming, research and development to find out how you can better consider the UX and apply it in your UI. Keep in mind that the number of mobile internet users is increasing day by day. So,… Read More »


Project Treble – Android Version Fragmentation Solved

By | August 18, 2018

Solved Yes, a longtime problem with Android has been solved. Yes, version fragmentation problem. Version fragmentation is often Android from different manufacturers had been stuck on different versions which makes it difficult for developers to support all variety of devices. Hopefully the problem is going to be solved. From Google’s perspective, an OS rollout is actually a three-stage… Read More »


How to listen to events from react native?

By | August 14, 2018

Hi friends, This is essentially a continuation of this post https://www.coderzheaven.com/2018/08/10/how-to-create-a-custom-native-imageview-in-android-for-reactnative/ Now we will listen to a click event from the image we just created. For that we have to add the ClickListener to the image in Android. Add below methods to the java class On the React Native Side The whole java class will look like this.