2.3.9 Nested Views Codehs May 2026

In CodeHS exercise 2.3.9: Nested Views, the goal is to practice building a hierarchical layout by placing multiple View components inside one another. This exercise is a foundational step in mobile app development, teaching you how to organize UI elements through "nesting," where one container (the parent) holds another (the child). Code Requirement Breakdown

To complete this exercise correctly, your code must meet the following criteria:

Hierarchy: Use at least four View components nested inside each other.

Unique Styles: Each View must have a different size and a different color.

Flexibility: You have creative control over the spacing, justification, and alignment. 2.3.9 nested views codehs

Note: The main parent container counts as the first of your four required views. Step-by-Step Implementation Guide

Define the Parent ViewStart with a root View that acts as the container for everything else. Assign it a base style like flex: 1 to fill the screen and a distinct background color.

Nest the Second ViewInside the parent, add another . Give this child a specific height and width (e.g., 200x200) and a second color. Use justifyContent and alignItems on the parent to center this view.

Nest the Third ViewPlace a third inside the second one. Make it smaller (e.g., 100x100) and choose a third color. In CodeHS exercise 2

Nest the Fourth ViewFinally, place the fourth inside the third. This will be your smallest component (e.g., 50x50) with a fourth unique color. Concept: Why We Nest Views

Nesting isn't just for making "Russian nesting doll" boxes; it is the backbone of real-world UI design:

Organization: It groups related elements together (like a profile picture inside a header bar).

Layout Control: Using a parent view allows you to align all its children at once using Flexbox properties like center or space-around. Core concepts and vocabulary

Modularity: It makes your code easier to read and maintain by breaking complex screens into smaller, manageable blocks. Restatement of Result

The 2.3.9 Nested Views exercise requires a four-level deep hierarchy of View components, each with unique color and size properties, to demonstrate mastery of layout organization and parent-child relationships in mobile development. Mobile Apps - Outline - CodeHS

Core concepts and vocabulary

• Parent view / Container: the outer view holding children.
• Child view / Subview: a view placed inside a parent.
• Layout: rules for positioning children (flow, flex, grid, absolute).
• Padding, margin, border: spacing between views and contents.
• Coordinate space: child coordinates are relative to their parent.
• Event propagation: events often bubble from child to parent (or can be captured).

Write-Up: 2.3.9 Nested Views

1. The Root Element

Every XML file needs one root element. In most CodeHS Android units, this is a LinearLayout.

<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">
<!-- Other items go here -->

</LinearLayout>