Android app development for beginners (with Kotlin)

Learn Kotlin basics for Android app development by declaring and initializing variables with var or val, using int data types, commenting, and printing unreadMessages.

Explore Kotlin data types for android, including float, double, string, and boolean, and learn immutability with val, type inference, and camel case naming. Understand string length and variable naming conventions.

Discover how variables hold values and behaviors in Android app development with Kotlin, using an int variable to decrement and compare to another value, and mastering Intellisense and print.

Explore string and char replace functions, type inference, and the char data type. Convert strings to numbers with to int and to float, noting possible exceptions.

Learn how Kotlin uses nullable types and the question mark to let variables hold float or boolean values as null, enabling null safety in Kotlin apps.

Learn to use arithmetic and assignment operators in Kotlin, including addition, subtraction, multiplication, division, modulus, and compound assignments; understand precedence, parentheses, and string concatenation.

Practice Kotlin basics by using readLine to capture input, declare a nullable string named name, print a welcome message, and review data types, function members, operators, and Android Studio intellisense.

Practice swapping two input numbers in Android Studio using a temp variable and reading lines for num1 and num2, then print the swapped results.

Develop tip calculator app that lets users enter a bill amount with an edit text, set tip percent with a seek bar, and calculate total payment for number of people.

Design and implement the app user interface in Android Studio using Kotlin, creating activity_main.xml with text views, edit text, seek bar, and button inside a constraint layout with IDs.

Design an Android UI with constraint layout, set horizontal and vertical constraints to center and align views, and move text to strings.xml to resolve hard coded warnings.

Write the tip calculator in Kotlin by reading the bill amount from the edit text and the tip percent from the seekbar, then compute tip and display the total payment.

Implement a seek bar to display tip percent in real time via on progress change and update the user interface with the total payment and tip amount using Kotlin.

Design the update UI for a tip calculator app by adding a number of people label, a seek bar, and a second text view, with IDs and a max 20.

Calculate each person’s share by dividing total payment (bill and tip) by number of people and display the result with a dollar sign while adjusting the seek bars in Android.

Learn how contraflow in Kotlin uses the if expression to control code flow, evaluate boolean conditions, and select between branches with else and else if, enabling conditional execution.

Write Kotlin code using readLine to read a number, convert to int, and use an if expression to print even when division by 2 leaves 0 remainder, else odd.

Enhance the tip calculator by guarding against empty input with an if check on the bill amount, displaying a toast when no number is entered and calculating when present.

Explore the difference between statements and expressions in Kotlin, where if is an expression that returns a value. Use it to compute the larger of two numbers.

Implement a rating system in Kotlin by reading a star number, using an if expression to map to messages such as excellent, and print the resulting string, handling invalid input.

Explore how Kotlin's when expression handles multiple conditions with and without an argument, replacing switch and if for clearer control flow, including prime number checks and concise condition combining.

Write a Kotlin program that reads two integers and a math operator using readLine, uses a when expression to perform the operation, and prints result or error for invalid operators.

Categorize user ages with ranges in Kotlin, using if and when expressions to map 12–18 to group A, 19–35 to group B, 36–66 to group C, and unknown otherwise.

Learn to write user defined functions in Kotlin, expanding on predefined functions like print, toInt, and toString. Define and call a rectangle area function from main to print the result.

Learn to extend functions with parameters to handle different inputs, using a two-parameter rectangle area function with width and length, demonstrating parameters vs arguments and function signature, enabling code reuse.

Define functions with a return type and parameters, use the return keyword to return a computed value such as a rectangle area, then print or use the result.

Write a Kotlin function isNumEven that accepts an int and returns true if even, false otherwise, using a simple divisibility by 2 check and sample inputs like 5 and 6.

Learn to implement a reusable calculate tip function in kotlin tip calculator app, replacing duplicated code across seek bar progress handlers and button clicks, and prevent divide by zero errors.

Declare and initialize arrays using arrayOf() to hold related values. Access and change elements with zero-based indices, and watch for array index out of bounds errors.

Declare and initialize a byte array named temperature of days with 14 elements, holding two weeks of air temperatures, sum the elements, and print the average.

Explore how to use for loops to iterate over arrays in Kotlin, sum elements, and write robust code that adapts to array size using the temperature days array.

Practice building a Kotlin app that reads ten numbers using a for loop, sums them in an int variable named sum, and prints the result with user prompts.

Explore listOf and mutableListOf in Kotlin to store values, distinguish immutable from mutable collections, access by index, iterate with for loops, and add or remove elements.

Learn how to use classes to encapsulate product properties and methods, create instances with constructors, and iterate over arrays to compute final prices in Kotlin.

Define a circle class with name, radius, and pi default 3.14, and a get area method. Create circles with radii 5, 7, 2, 9, store in array, and print areas.

Learn how enum classes define a safe data type with a fixed set of constants like north, south, east, and west, avoiding string pitfalls.

Define an enum named categories with two constants electronics and luggage, then use it in the app constructor to replace string values for cleaner code.

Master Kotlin exception handling with try catch to manage arithmetic and number format errors, including division by zero, and utilize finally for reliable cleanup and friendly messages.

Create the Android SDK-based English stories app for kids and English learners, featuring a main activity with a list view and a collapsing toolbar.

Design the main activity to display a scrollable list of story titles using a list view. Bind with an array adapter and respond to clicks with a toast.

Design a full text activity with a scrolling view to display selected story. Navigate from main activity, pass the item index via intent putExtra, and read it to render story.

Create a story class with title and full text, store stories in a singleton data object, and populate the list to display the selected story full text.

Build Android notes app using SQLite. Create a main activity with a list view and FAB to add notes, and a detail activity to insert, update, or delete notes.

Design the activity UI with a list view and a floating action button. Then create a notes table with title, description, and an id as primary key to identify rows.

Design and implement a local Android Kotlin app database with SQLiteOpenHelper, creating a notes table (id, title, description) via onCreate, and use db.execSQL and Cursor for data access.

Create a notes database with the my notes SQLite open helper, bind a list view to the notes table using a simple cursor adapter, and clean up in onDestroy.

Design the note details screen for adding, editing, and deleting notes, including an up button and a save and delete action bar menu.

Insert a new note into the notes table by creating a writable database via the MyNotesSQLiteOpenHelper and using ContentValues for title and description, with a save action and toast feedback.

Explore the Android activity lifecycle, including onCreate, onStart, onResume, onPause, onStop, onDestroy, and onRestart; move the list-binding code to onStart so notes update immediately.

Open a note by tapping a list item and pass its id to details. Use the fab to create new notes (id zero) and load title and description.

Learn to update existing notes or insert new ones using content values and db.update, implement delete with db.delete after a confirmation alert, and finish the detail activity.

Learn to build a quotes app with recycler view and card view to display quotes, and use intents to open details and share quotes across apps.

Design a database as the data source with two linked tables—quote categories and quotes—and insert default values, then display categories in a recycler view with a card view.

Create a category item layout with a card view to display quote category's image and title inside a recycler view, and prepare it for the adapter.

Learn to write a custom recycler view adapter in Android Kotlin, including a view holder and binding image and text in a card view for efficient recycling.

Bind the adapter to the recycler view and set a linear layout manager to display quote categories read from the database in a vertical list.

Learn to implement a reusable item click listener for a recycler view by passing a function to the adapter, opening the quote details activity with the selected category id.

Implement the quote details activity by adding a quotes table with quote and category_id and an insert_quote method, then design a card layout with constraint layout, guidelines, and unicode quotes.

Develop a quotes details screen in Android using Kotlin. Create a RecyclerView adapter and view holder, bind quotes from SQLite, and enable long-click sharing via intents with ripple effects.