Arrangement and alignment in Android Kotlin - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of LinearLayout in Android?

LinearLayout arranges its child views in a single row or column, either horizontally or vertically.

intermediate

How does gravity differ from layout_gravity in Android layouts?

gravity controls the alignment of content inside a view.
layout_gravity controls how the view itself is positioned inside its parent.

beginner

What does match_parent do when used for width or height?

It makes the view expand to fill the size of its parent container in that dimension.

intermediate

Explain the role of weight in a LinearLayout.

weight lets child views share available space proportionally in a LinearLayout.

advanced

What is the difference between RelativeLayout and ConstraintLayout?

RelativeLayout positions views relative to siblings or parent edges.
ConstraintLayout is more flexible and efficient, allowing complex positioning with constraints.

Which layout arranges child views in a single column or row?

A FrameLayout

B LinearLayout

C ConstraintLayout

D RelativeLayout

LinearLayout arranges children in one direction: horizontally or vertically.

What does layout_gravity="center" do?

A Centers the content inside the view

B Aligns the view to the top

C Centers the view inside its parent

D Makes the view fill the parent

layout_gravity controls the view's position inside its parent container.

If a child view has layout_weight="1" in a horizontal LinearLayout, what happens?

A It shares extra space equally with other weighted views

B It overlaps other views

C It shrinks to minimum size

D It gets no extra space

Weight distributes leftover space proportionally among weighted views.

Which attribute aligns content inside a TextView?

A gravity

B padding

C layout_gravity

D margin

gravity aligns the content inside the view.

Which layout is best for complex view positioning with flexible constraints?

A FrameLayout

B RelativeLayout

C LinearLayout

D ConstraintLayout

ConstraintLayout allows flexible and efficient positioning using constraints.

Describe how you would center a button inside a parent layout using Android XML attributes.

Think about how to position the button itself and its content.

Explain how weight works in a LinearLayout and why it is useful.

Imagine sharing leftover space among views.

Practice

1. Which property in a LinearLayout controls whether items are stacked vertically or horizontally?

easy

A. layout_width

B. gravity

C. orientation

D. padding

Solution

1. Step 1: Understand LinearLayout properties

   The orientation property defines if children are stacked vertically or horizontally.

2. Step 2: Differentiate from other properties

   gravity controls alignment inside the container, not stacking direction.

3. Final Answer:

   orientation -> Option C

4. Quick Check:

   Stack direction = orientation [OK]

Hint: Stacking direction is set by orientation property [OK]

Common Mistakes:

• Confusing gravity with orientation
• Thinking padding controls stacking
• Mixing layout_width with arrangement

2. Which of the following is the correct syntax to center all child views inside a LinearLayout using gravity in Kotlin XML?

easy

A. android:orientation="center"

B. android:gravity="center"

C. android:layout_gravity="center"

D. android:align="center"

Solution

1. Step 1: Identify property for child alignment inside container

   android:gravity aligns children inside the LinearLayout.

2. Step 2: Check syntax correctness

   android:gravity="center" is the correct attribute and value to center children.

3. Final Answer:

   android:gravity="center" -> Option B

4. Quick Check:

   Center children = android:gravity="center" [OK]

Hint: Use android:gravity to align children inside layout [OK]

Common Mistakes:

• Using layout_gravity instead of gravity for children
• Setting orientation to center (invalid)
• Using non-existent align attribute

3. Given this Kotlin XML snippet:

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal"
    android:gravity="center_vertical">
    <Button android:text="A" />
    <Button android:text="B" />
</LinearLayout>

How will the buttons be arranged on the screen?

medium

A. Buttons side by side horizontally and centered vertically

B. Buttons stacked vertically aligned to bottom

C. Buttons side by side horizontally aligned to top

D. Buttons stacked vertically and centered horizontally

Solution

1. Step 1: Analyze orientation property

   android:orientation="horizontal" means children are placed side by side horizontally.

2. Step 2: Analyze gravity property

   android:gravity="center_vertical" aligns children vertically centered inside the container.

3. Final Answer:

   Buttons side by side horizontally and centered vertically -> Option A

4. Quick Check:

   Horizontal orientation + center_vertical gravity = Buttons side by side horizontally and centered vertically [OK]

Hint: Orientation sets direction; gravity sets alignment inside container [OK]

Common Mistakes:

• Confusing orientation with gravity effects
• Assuming vertical stacking with horizontal orientation
• Ignoring gravity vertical centering

4. What is wrong with this Kotlin XML layout snippet?

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    android:gravity="center_horizontal">
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center" />
</LinearLayout>

medium

A. layout_gravity="center" on TextView is redundant here

B. Using both gravity and layout_gravity causes conflict

C. orientation="vertical" is invalid for LinearLayout

D. Missing closing tag for LinearLayout

Solution

1. Step 1: Understand gravity vs layout_gravity

   android:gravity on LinearLayout aligns children inside it; layout_gravity aligns the child itself inside its parent.

2. Step 2: Check redundancy in this context

   Since LinearLayout has gravity="center_horizontal", the child TextView is already centered horizontally, so layout_gravity="center" on TextView is unnecessary.

3. Final Answer:

   layout_gravity="center" on TextView is redundant here -> Option A

4. Quick Check:

   Redundant layout_gravity when parent gravity centers children [OK]

Hint: Parent gravity centers children; child layout_gravity may be redundant [OK]

Common Mistakes:

• Thinking orientation="vertical" is invalid
• Confusing gravity and layout_gravity roles
• Missing closing tags (actually present here)

5. You want to create a LinearLayout that stacks three buttons vertically, but the middle button should be aligned to the right edge while the others are centered horizontally. Which arrangement and alignment setup achieves this?

hard

A. Set orientation="vertical" on LinearLayout, gravity="center_horizontal", and layout_gravity="center_horizontal" on the middle button

B. Set orientation="horizontal" on LinearLayout, gravity="center_vertical", and layout_gravity="end" on the middle button

C. Set orientation="vertical" on LinearLayout, gravity="end", and layout_gravity="center_horizontal" on the middle button

D. Set orientation="vertical" on LinearLayout, gravity="center_horizontal", and layout_gravity="end" on the middle button

Solution

1. Step 1: Set vertical stacking

   orientation="vertical" stacks buttons top to bottom.

2. Step 2: Center all buttons horizontally by default

   Set gravity="center_horizontal" on LinearLayout to center children horizontally.

3. Step 3: Align middle button to right edge

   Override middle button's alignment with layout_gravity="end" to push it to the right.

4. Final Answer:

   orientation="vertical", gravity="center_horizontal", layout_gravity="end" on middle button -> Option D

5. Quick Check:

   Vertical stack + center default + override middle button end [OK]

Hint: Use layout_gravity on child to override parent gravity alignment [OK]

Common Mistakes:

• Using horizontal orientation instead of vertical
• Setting gravity="end" on parent causing all children right aligned
• Not overriding middle button alignment