Open the main activity, extend the AppCompat activity class, and initialize the app lifecycle by overriding a lifecycle method. Inflate the layout using setContentView to connect activity_main with the manifest.

Learn how Android apps declare the entry point in the manifest, inflate layouts in onCreate, and edit layouts with the design tab and XML, using string resources and colors.

Explore the Android activity lifecycle by using logcat to observe onCreate, onStart, onResume, onPause, onStop, onRestart, and onDestroy, and learn how overriding these methods aids debugging and understanding app behavior.

Convert a constraint layout to a linear layout and create vertical or horizontal orientations to arrange views, using wrap_content, match_parent, margins, padding, and dp/sp.

Learn how choosing the minimum and target Android SDK affects device coverage and feature availability, and how vector assets become natively supported with Android 5.1, with Gradle configuration.

Connect a main activity to read a name from an edit text, attach a click listener to the update button, and display a personalized hello in a text view.

Learn to hide the keyboard from a window by using an input method manager retrieved via getSystemService in an Android Kotlin main activity, improving user flow.

Build a counter app by setting a starting number or choosing a random start, then increment or decrement by a chosen amount while viewing a calculation summary in linear layouts.

Explores building a multi-row layout for a counter app using horizontal and vertical linear layouts, edit texts, and buttons with weights, IDs, fonts, and color resources.

Learn to build an Android main activity in Kotlin by inflating a layout, wiring four buttons with click listeners, and using lateinit views for text inputs and outputs.

Implement main activity features in Kotlin: generate random numbers from -100 to 100 and display them, handle input with defaults, and enable increment and decrement with a live summary.

Explore how constraint layout enables precise view positioning through horizontal and vertical constraints, enabling flat view hierarchies and more complex layouts with necessary rules for each view.

Explore constraint layout basics by applying and removing constraints, anchoring views to the parent, and linking views for responsive, orientation-aware designs using margins, wrap content, match constraint, and percent sizing.

Explore constraint layout basics by building and styling horizontal and vertical chains, aligning chain centers, and controlling space with horizontal and vertical weights.

Design the coin flip app layout using constraint layout, create vector icons for heads, tails, and flip, add a simulate switch, an image view, and buttons for flip and reset.

Build an Android Kotlin layout that tracks coin flips with text views for total flips, heads, and tails, plus percent progress bars and an edit text with a simulate button.

Refine the coin flip app layout by cleaning up view IDs, adjusting margins, and tuning vertical bias for portrait, landscape, and tablet orientations.

Link the switch and flip, reset, and simulate buttons with onCreate listeners, and define late-initialized views for the coin image, counts, progress bars, and simulation input.

Implement reset and simulation features in a Kotlin Android main activity, updating counters and text views, toggling visibility with a switch, preventing division by zero, and refining percentage precision.

Preview the diaper tracker app for newborns, logging dirty, wet, or dry diapers with optional times using radio buttons, with a scrollable history and a reset button.

Build a diaper tracker layout with constraint layout, create color palettes and vector assets, implement a horizontal radio group for diaper types, and apply font styles with a default selection.

Extend an Android layout by adding a time edit text, styled controls, and two action buttons, plus a scrollable diaper changes list with image and text entries.

Refine the diaper tracker layout in Android with Kotlin by fixing the scroll view using match_constraint, applying text styles, and adding a bottom diaper count while testing in multiple orientations.

Learn to persist data through screen rotations in Android development with Kotlin using on save instance state and a bundle.

Explain the limits of onSaveInstanceState for configuration changes and show how a view model and binding replace find by id to persist UI data.

Refactor the Motivate Me app using view binding, enable it in the Gradle file, and access views via binding instead of findViewById. The method is faster than data binding.

Master view binding in Android with Kotlin by wiring click listeners, obtaining user input, selecting a random motivational message, updating the UI, and preserving state with bundles.

Learn to refactor a counter app in Kotlin using view binding, enabling binding in Gradle, inflating layouts, and handling clicks, text inputs, and random number updates.

Refactor the counter app to use view binding, implementing a change number function with increment and decrement, and persist state with a bundle across rotations. Explore data binding’s architectural benefits.