LinearLayout

Think of LinearLayout as a container that arranges UI elements in a straight line — either vertically (top → bottom) or horizontally (left → right).

For example:

• Buttons in a row

• Form fields stacked one below another

It is one of the most basic layout types used when building apps in Android Studio.

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1. Definition

LinearLayout is a ViewGroup in Android that arranges its child views in a single direction (horizontal or vertical).

In simple words:
➡ It places UI components one after another in a line.

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2. Purpose

The main purpose of LinearLayout is to:

• Organize UI components in a simple line structure

• Create forms, menus, toolbars

• Control space distribution using weights

• Keep UI clean and structured

Example uses:

• Login screen

• Navigation bar

• Button row

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3. Syntax

Basic XML syntax:

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

</LinearLayout>

Explanation:

• layout_width → width of layout

• layout_height → height of layout

• orientation → direction of items

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4. Types of Orientation

Vertical Layout

Elements appear top to bottom

android:orientation="vertical"

Example order:

TextView
EditText
Button

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Horizontal Layout

Elements appear left to right

android:orientation="horizontal"

Example:

Button  Button  Button

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5. Important Properties

1. orientation

Defines layout direction.

vertical
horizontal

Example:

android:orientation="vertical"

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2. layout_weight

Controls how much space a view occupies.

Example:

<Button
    android:layout_weight="1"/>

If 3 buttons all have weight 1 → space divided equally.

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3. gravity

Aligns children inside layout.

Example:

android:gravity="center"

Options:

• center

• left

• right

• top

• bottom

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4. layout_gravity

Controls position of a child view inside parent.

Example:

android:layout_gravity="center"

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5. padding

Adds space inside the layout.

Example:

android:padding="16dp"

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6. Important Methods

These methods are usually used in Java / Kotlin code.

1. setOrientation()

Sets layout direction.

linearLayout.setOrientation(LinearLayout.VERTICAL);

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2. setGravity()

Aligns children.

linearLayout.setGravity(Gravity.CENTER);

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3. addView()

Adds a view dynamically.

linearLayout.addView(button);

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4. removeView()

Removes a view.

linearLayout.removeView(textView);

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7. Real-Time Examples

Example 1: Login Form

<LinearLayout
    android:orientation="vertical"
    android:padding="20dp"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <EditText
        android:hint="Email"/>

    <EditText
        android:hint="Password"/>

    <Button
        android:text="Login"/>

</LinearLayout>

Layout result:

Email Field
Password Field
Login Button

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Example 2: Button Row

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

    <Button android:text="Yes"/>
    <Button android:text="No"/>
    <Button android:text="Cancel"/>

</LinearLayout>

Result:

Yes   No   Cancel

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Example 3: Equal Space Buttons (Weight)

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

    <Button
        android:text="A"
        android:layout_weight="1"
        android:layout_width="0dp"/>

    <Button
        android:text="B"
        android:layout_weight="1"
        android:layout_width="0dp"/>

</LinearLayout>

Both buttons take equal width.

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8. Advantages

✔ Simple to use
✔ Good for small layouts
✔ Easy alignment
✔ Supports weight-based sizing

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9. Disadvantages

❌ Too many nested LinearLayouts can slow UI
❌ Less flexible compared to ConstraintLayout

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10. Simple One-Line Summary

LinearLayout = A container that arranges UI elements in a straight line (horizontal or vertical).