# Category Archives: ANDROID

## Implement a PrefixMapSum class with the following methods

By | July 5, 2023

insert(key: str, value: int): Set a given key’s value in the map. If the key already exists, overwrite the value. sum(prefix: str): Return the sum of all values of keys that begin with a given prefix. For example, you should be able to run the following code: mapsum.insert(“columnar”, 3) assert mapsum.sum(“col”) == 3 mapsum.insert(“column”, 2) assert mapsum.sum(“col”) ==… Read More »

## Problem: You are given N identical eggs and access to a building with k floors. Your task is to find the lowest floor that will cause an egg to break, if dropped from that floor.

By | July 2, 2023

You are given N identical eggs and access to a building with k floors. Your task is to find the lowest floor that will cause an egg to break, if dropped from that floor. Once an egg breaks, it cannot be dropped again. If an egg breaks when dropped from the xth floor, you can assume it will… Read More »

## Create an algorithm that arranges them in order to form the largest possible integer

By | July 2, 2023

Given a list of numbers, create an algorithm that arranges them in order to form the largest possible integer. For example, given [10, 7, 76, 415], you should return 77641510. Javascript function largestNumber(nums) {  nums.sort((a, b) => {    const order1 = String(a) + String(b);    const order2 = String(b) + String(a);    return order2.localeCompare(order1);  });  return nums.join(”);}//… Read More »

## Write a program to compute the in-order traversal of a binary tree using O(1) space.

By | June 25, 2023

Python Java Javascript These implementations use the Morris Traversal algorithm to perform in-order traversal without using any additional space other than O(1). The algorithm establishes temporary links between nodes and their predecessors, allowing efficient traversal and processing of the tree nodes. Note: The code examples assume that the tree nodes have a val, left, and right property to… Read More »

## Flutter vs. React Native: Unraveling the Performance Battle

By | June 25, 2023

Introduction: When it comes to developing cross-platform mobile applications, Flutter and React Native have emerged as the two dominant frameworks. As developers seek to create high-performing apps, it’s crucial to understand the performance capabilities of each framework. In this article, we will delve into the performance aspects of Flutter and React Native, examining their strengths and weaknesses to… Read More »

## Different ways of making rounded corner images in flutter

By | June 25, 2023

Example 1: ClipRRect dartCopy codeClipRRect( borderRadius: BorderRadius.circular(10.0), child: Image.asset(‘assets/images/image.jpg’), ) In this example, the ClipRRect widget is used to clip the child Image with rounded corners. The borderRadius property defines the radius of the corners. Example 2: BoxDecoration dartCopy codeContainer( decoration: BoxDecoration( borderRadius: BorderRadius.circular(10.0), image: DecorationImage( image: AssetImage(‘assets/images/image.jpg’), fit: BoxFit.cover, ), ), ) Here, a Container is used… Read More »

## Given an absolute pathname that may have . or .. as part of it, return the shortest standardized path

By | June 25, 2023

Given an absolute pathname that may have . or .. as part of it, return the shortest standardized path. For example, given “/usr/bin/../bin/./scripts/../”, return “/usr/bin/”. To obtain the shortest standardized path from an absolute pathname that may contain “.” or “..” as part of it, you can follow these steps: Here’s an example Python code that implements this… Read More »

## Riverpod in Flutter – Simplest Example Ever

By | June 22, 2023

In this example, we create a simple Flutter application that displays a counter and increments the count when a FloatingActionButton is pressed. The state management is handled by Riverpod. Here’s a breakdown of the code: When you run this code, you will see a simple app with an app bar, a counter in the center of the screen,… Read More »

## Connect 4 is a game where opponents take turns dropping red or black discs into a 7 x 6 vertically suspended grid.

By | June 22, 2023

The game ends either when one player creates a line of four consecutive discs of their color (horizontally, vertically, or diagonally), or when there are no more spots left in the grid. Design and implement Connect 4. To design and implement Connect 4, we can follow these steps: Here’s an example implementation of Connect 4 in Python: class… Read More »

## Roman numeral format to decimal.

By | June 22, 2023

Given a number in Roman numeral format, convert it to decimal. The values of Roman numerals are as follows: { ‘M’: 1000, ‘D’: 500, ‘C’: 100, ‘L’: 50, ‘X’: 10, ‘V’: 5, ‘I’: 1 } In addition, note that the Roman numeral system uses subtractive notation for numbers such as IV and XL. For the input XIV, for… Read More »

## Smallest sparse number greater than or equal to N.

By | June 20, 2023

We say a number is sparse if there are no adjacent ones in its binary representation. For example, 21 (10101) is sparse, but 22 (10110) is not. For a given input N, find the smallest sparse number greater than or equal to N. Do this in faster than O(N log N) time. Solution in Java and Javascript Java… Read More »

## 10 Best Flutter Packages to use in your app

By | June 19, 2023

## Problem Solving – IP addresses must follow the format A.B.C.D, where A, B, C, and D are numbers between 0 and 255.

By | June 19, 2023

Given a string of digits, generate all possible valid IP address combinations. IP addresses must follow the format A.B.C.D, where A, B, C, and D are numbers between 0 and 255. Zero-prefixed numbers, such as 01 and 065, are not allowed, except for 0 itself. For example, given “2542540123”, you should return [‘254.25.40.123’, ‘254.254.0.123’]. To generate all possible… Read More »

## MVVM in Android – ViewModels, ViewModelScope, Retrofit all with a Simple Example.

By | June 6, 2021

Let’s learn how to implement MVVM in Android. It’s actually really simple. ViewModel is just another class that that implements the main Business Logic. ViewModel is a middle man between your view and your Data class(Repo/any Data Provider). It can be represented simply like this. Here the View just displays the data. ViewModel doesn’t know where the data… Read More »

By | December 6, 2020

In this article, we will see how we can use BLoc to Theme your app in Flutter. To understand BLoC with a real world example, you can refer to my previous post on BLoC here. Part 1 Part 1 For this demo also we will need the below plugins If you follow my previous tutorial, it would be… Read More »

## How to use YouTube APIs and Play YouTube videos in Flutter.

By | August 27, 2020

In this article we are gonna talk about how to use YouTube API’s and play YouTube videos in Flutter. Watch Video Tutorial Add Dependencies Open pubspec.yaml file in your Flutter project and add below dependencies Now, Let’s create two screens Home Screen Video Player Screen In the HomeScreen we will show the list of videos. API Key We… Read More »

## Reusable Widgets & Reusable Custom AppBars in Flutter.

By | July 17, 2020

We will be talking about how to reuse widgets and create custom reusable AppBars in this article. It’s so easy in flutter. Composing widgets and making it a more powerful and reusable one is so much easy in flutter. Watch Video Tutorial Let’s start at one of the wrong ways that beginners used to do. Let’s say I… Read More »

## Chat Application in Flutter Using Socket IO

By | May 18, 2020

In this article we will see how we can create a chat application in flutter using Socket IO node js server. For this we need to have a server installed with Node js Socket IO and related dependencies So let’ start with Flutter. Here we need three screens Login screen Chat Users List screen Chat Screen. Login Screen… Read More »

By | April 18, 2019

This article shows how to implement Bottom navigation using Tabs in Flutter.     Watch Video Tutorial     For that we need to have a TabController and a TabBarView Widget.   Create Tabs   This is our demo tab layout widget. Create a new file name FirstTab.dart and copy the contents into it. You can create other… Read More »

## Flutter – Android, iOS , Native communication Simple Demo

By | December 24, 2018

Hello Devs, You know flutter is now a hot topic. Learning flutter will always help in your future career. In this article we will see how we can communicate between Flutter and Android. Watch Video Tutorial MethodChannel Flutter communicate with Native using “MethodChannel“. So you have to create a method channel with a constant as identifier. Make sure… Read More »

## Is Javascript Multithreaded? How it handles asynchronous actions?

By | December 14, 2018

Javascript is a single threaded application. That means you cannot run more than one script at one time to modify DOM or something. But there are something called “Worker Threads” that spans separate threads outside your application that can do complex tasks which is linked by a Callback method. What is a Web Worker? When executing scripts in… Read More »

## What is Context in Android and What is the proper way to use it?

By | December 7, 2018

Lets see what a Context is… Context : Current State of the application. Context : Handle of the application. Context : Provides access to the resources, preferences, accessing database etc. Activity inherits from the Context. Context is the most important part of the Android application and its everywhere. If you wrongly use Context, it can lead to memory… Read More »

## How to use Theme in a Flutter App?

By | November 14, 2018

In this article, I will tell you a simple way to theme a flutter app. Here is a simple code that illustrates that. We use the theme property of each widget to theme it. For example, to theme the whole application, we would do something like this. Take a look at the theme property of the MaterialApp. You… Read More »

## Using Content Resolver to List Contacts – Android

By | October 31, 2018

Here is a simple example to list contacts in android using the Content Resolver. Note : You need to have two things before accessing contacts. 1. Contacts Permission in the Android Manifest 2. Ask Runtime permission from the user Code Here is our MainActivity that lists the contacts. MainActivity.java Adapter Class Below is the adapter class for the… Read More »

## Toast at the center of the screen – Android Tip # 2

By | October 30, 2018

Here is Tip # 2 Toast at Center of the Screen