LinearLayout (Java)

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LinearLayout stacks children vertically or horizontally. It’s ideal for simple rows/columns and works great inside a ScrollView. Mastering a few attributes—orientation, gravity, layout_gravity, and layout_weight—covers 90% of use-cases.

Core Properties (Cheat Sheet)

Attribute	What it affects	Tips
android:orientation	Stack direction (vertical \| horizontal)	Choose row vs column
android:gravity	How the parent positions all its children	e.g., center_horizontal
android:layout_gravity	How a child is placed inside its parent	e.g., right align one button
android:baselineAligned	Align baselines in a horizontal row	Use when you want text to line up
android:weightSum	Total weight of a row/column (optional)	Usually not needed; Android sums automatically
layout_weight	Proportional distribution in the orientation direction	Use with 0dp width/height to “stretch”

Visual Intuition

Vertical

Children stacked top → bottom

Horizontal

Children laid out left → right

Weight

Divide remaining space proportionally

Example 1 — Weighted Buttons Row (1:2 ratio)

Cancel

Save

Result: first button ≈ 33%, second ≈ 67%

<!-- res/layout/row_actions.xml -->
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal">

    <Button
        android:text="Cancel"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="1" />

    <Button
        android:text="Save"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="2" />

</LinearLayout>

Why this works: In a horizontal LinearLayout, children with layout_width="0dp" and non-zero layout_weight split the remaining row width.

Example 2 — Profile Column (Centered vertical stack)

Avatar

Name

Bio

<!-- res/layout/view_profile.xml -->
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    android:gravity="center_horizontal"
    android:padding="16dp">

    <ImageView
        android:src="@drawable/ic_avatar"
        android:layout_width="120dp"
        android:layout_height="120dp" />

    <TextView
        android:text="Sonu Kumar Pandit"
        android:textStyle="bold"
        android:textSize="18sp"
        android:layout_marginTop="12dp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

    <TextView
        android:text="Android Developer • Educator"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

</LinearLayout>

Gravity vs layout_gravity: Here, parent android:gravity="center_horizontal" centers all children. If you wanted only the last TextView centered, you would put android:layout_gravity="center_horizontal" on that child.

Example 3 — Two-Column Form (Nested rows with baseline alignment)

We build a vertical column of horizontal rows. Each row uses baseline alignment so labels and fields line up perfectly.

<!-- res/layout/form_two_column.xml -->
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

  <LinearLayout
      android:orientation="horizontal"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:baselineAligned="true">

      <TextView
          android:text="Email"
          android:layout_width="0dp"
          android:layout_height="wrap_content"
          android:layout_weight="1" />

      <EditText
          android:inputType="textEmailAddress"
          android:layout_width="0dp"
          android:layout_height="wrap_content"
          android:layout_weight="2" />

  </LinearLayout>

  <LinearLayout
      android:orientation="horizontal"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:layout_marginTop="8dp"
      android:baselineAligned="true">

      <TextView
          android:text="Password"
          android:layout_width="0dp"
          android:layout_height="wrap_content"
          android:layout_weight="1" />

      <EditText
          android:inputType="textPassword"
          android:layout_width="0dp"
          android:layout_height="wrap_content"
          android:layout_weight="2" />

  </LinearLayout>

</LinearLayout>

Baseline magic: android:baselineAligned="true" makes text baselines line up even if controls have different intrinsic heights.

Gravity vs layout_gravity

<!-- Parent centers all children -->
<LinearLayout
    android:gravity="center_horizontal" ... > ... </LinearLayout>

<!-- Only this child is pushed to the end -->
<Button android:layout_gravity="end" ... />

Performance & Best Practices

Minimize nesting: A few nested LinearLayouts are okay, but avoid deep trees. Use ConstraintLayout for complex screens.
Use weights sparingly: Weights are powerful but slightly more expensive to measure; prefer fixed or wrap sizes where possible.
In ScrollView: The child LinearLayout should typically be wrap_content in height to avoid infinite height issues.
RTL safety: When mixing with Relative/Constraint, prefer start/end over left/right.

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