LazyGrid in Android Kotlin - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a vertical LazyVerticalGrid with 2 columns.

Android Kotlin

LazyVerticalGrid(columns = GridCells.Fixed([1])) {
    items(10) { index ->
        Text(text = "Item $index")
    }
}

Drag options to blanks, or click blank then click option'

A2

B3

C4

D1

Attempts:

3 left

💡 Hint

Common Mistakes

Using a number outside GridCells.Fixed() instead of inside.

Confusing rows with columns.

The GridCells.Fixed(2) creates a grid with exactly 2 columns.

2fill in blank

medium

Complete the code to add padding of 8.dp around each grid item.

Android Kotlin

LazyVerticalGrid(columns = GridCells.Fixed(2)) {
    items(5) { index ->
        Text(text = "Item $index", modifier = Modifier.[1](8.dp))
    }
}

Drag options to blanks, or click blank then click option'

Amargin

Bsize

Cpadding

Dborder

Attempts:

3 left

💡 Hint

Common Mistakes

Using margin which is not a Compose modifier.

Using size which changes the size, not padding.

The padding modifier adds space inside the item's boundary.

3fill in blank

hard

Fix the error in the code by completing the blank to specify the grid's orientation as horizontal.

Android Kotlin

LazyVerticalGrid(columns = GridCells.Fixed(3), [1] = Orientation.Horizontal) {
    items(6) { index ->
        Text(text = "Item $index")
    }
}

Drag options to blanks, or click blank then click option'

Aorientation

Bdirection

ClayoutDirection

DscrollOrientation

Attempts:

3 left

💡 Hint

Common Mistakes

Using direction which is not a valid parameter here.

Confusing layoutDirection with orientation.

The correct parameter to set grid orientation is orientation.

4fill in blank

hard

Fill both blanks to create a LazyVerticalGrid with 3 fixed columns and add a background color of Color.LightGray to each item.

Android Kotlin

LazyVerticalGrid(columns = GridCells.[1](3)) {
    items(4) { index ->
        Box(modifier = Modifier.background([2]).padding(8.dp)) {
            Text(text = "Item $index")
        }
    }
}

Drag options to blanks, or click blank then click option'

AFixed

BAdaptive

CColor.LightGray

DColor.Blue

Attempts:

3 left

💡 Hint

Common Mistakes

Using Adaptive instead of Fixed for fixed columns.

Using wrong color values or missing the color import.

GridCells.Fixed(3) sets 3 columns. Color.LightGray sets the background color.

5fill in blank

hard

Fill all three blanks to create a LazyVerticalGrid with adaptive columns of minimum 100.dp width, add 12.dp padding around each item, and set the text color to Color.Black.

Android Kotlin

LazyVerticalGrid(columns = GridCells.[1](100.dp)) {
    items(3) { index ->
        Text(text = "Item $index", modifier = Modifier.padding([2]), color = [3])
    }
}

Drag options to blanks, or click blank then click option'

AFixed

BAdaptive

CColor.Black

D12.dp

Attempts:

3 left

💡 Hint

Common Mistakes

Using Fixed instead of Adaptive for adaptive columns.

Mixing up padding and color values.

GridCells.Adaptive(100.dp) creates columns that adapt with minimum width 100.dp. Padding is 12.dp and text color is black.

Practice

1. What is the main purpose of using LazyVerticalGrid in Android Compose?

easy

A. To efficiently display a scrollable grid of items by creating only visible items

B. To create a fixed number of buttons in a row

C. To display a list of items vertically without any grid layout

D. To load all items at once for faster access

Solution

1. Step 1: Understand LazyVerticalGrid behavior

   LazyVerticalGrid creates only the visible grid items to save memory and improve performance.

2. Step 2: Compare with other options

   Options A and B describe different layouts, and D is inefficient because it loads all items at once.

3. Final Answer:

   To efficiently display a scrollable grid of items by creating only visible items -> Option A

4. Quick Check:

   LazyGrid creates visible items only = C [OK]

Hint: LazyGrid creates only visible items for efficiency [OK]

Common Mistakes:

• Thinking LazyGrid loads all items at once
• Confusing LazyGrid with a simple vertical list
• Assuming LazyGrid fixes number of buttons only

2. Which of the following is the correct way to define a fixed number of columns in a LazyVerticalGrid?

easy

A. LazyVerticalGrid(columns = GridCells.Fixed("3")) { /* items */ }

B. LazyVerticalGrid(columns = GridCells.Fixed(3)) { /* items */ }

C. LazyVerticalGrid(columns = 3) { /* items */ }

D. LazyVerticalGrid(columns = GridCells.Adaptive(100.dp)) { /* items */ }

Solution

1. Step 1: Recall syntax for fixed columns

   The correct syntax uses GridCells.Fixed with an integer number of columns.

2. Step 2: Analyze each option

   LazyVerticalGrid(columns = GridCells.Fixed(3)) { /* items */ } uses GridCells.Fixed(3) correctly. LazyVerticalGrid(columns = GridCells.Adaptive(100.dp)) { /* items */ } uses adaptive columns, not fixed. LazyVerticalGrid(columns = 3) { /* items */ } passes an integer directly, which is invalid. LazyVerticalGrid(columns = GridCells.Fixed("3")) { /* items */ } passes a string instead of an integer.

3. Final Answer:

   LazyVerticalGrid(columns = GridCells.Fixed(3)) { /* items */ } -> Option B

4. Quick Check:

   Fixed columns use GridCells.Fixed(number) = D [OK]

Hint: Use GridCells.Fixed(number) for fixed columns [OK]

Common Mistakes:

• Passing integer directly instead of GridCells.Fixed
• Using string instead of integer for column count
• Confusing fixed with adaptive columns

3. Given the code snippet:

LazyVerticalGrid(columns = GridCells.Fixed(2)) {
  items(4) { index ->
    Text(text = "Item $index")
  }
}

How many columns and rows will be visible if the grid shows all items?

medium

A. 2 columns and 2 rows

B. 4 columns and 1 row

C. 1 column and 4 rows

D. 2 columns and 4 rows

Solution

1. Step 1: Understand columns and items

   The grid has 2 fixed columns and 4 items total.

2. Step 2: Calculate rows needed

   With 2 columns, 4 items fill 2 rows (2 items per row).

3. Final Answer:

   2 columns and 2 rows -> Option A

4. Quick Check:

   4 items / 2 columns = 2 rows [OK]

Hint: Rows = total items ÷ columns (round up) [OK]

Common Mistakes:

• Assuming columns equal number of items
• Confusing rows and columns count
• Ignoring fixed columns setting

4. Identify the error in this LazyVerticalGrid code:

LazyVerticalGrid(columns = GridCells.Fixed(3)) {
  items(5) { index ->
    Text(text = "Item $index")
  }
  item {
    Text(text = "Footer")
  }
}

medium

A. Using both items and item inside LazyVerticalGrid is invalid

B. The item block should be inside items block

C. No error; code is correct

D. GridCells.Fixed cannot be used with 3 columns

Solution

1. Step 1: Check usage of items and item

   LazyVerticalGrid supports both items (multiple) and item (single) blocks for content.

2. Step 2: Verify GridCells.Fixed usage

   GridCells.Fixed(3) is valid to set 3 columns.

3. Final Answer:

   No error; code is correct -> Option C

4. Quick Check:

   items and item can coexist = B [OK]

Hint: items and item blocks can be mixed in LazyGrid [OK]

Common Mistakes:

• Thinking item block must be inside items
• Assuming GridCells.Fixed(3) is invalid
• Believing multiple content blocks cause error

5. You want to create a photo gallery with images that adapt to screen width, showing as many columns as fit with a minimum size of 120.dp per item. Which LazyVerticalGrid setup is correct?

hard

A. LazyVerticalGrid(columns = GridCells.Fixed(3)) { /* images */ }

B. LazyVerticalGrid(columns = GridCells.Fixed(120)) { /* images */ }

C. LazyVerticalGrid(columns = GridCells.Adaptive(3)) { /* images */ }

D. LazyVerticalGrid(columns = GridCells.Adaptive(120.dp)) { /* images */ }

Solution

1. Step 1: Understand adaptive columns

   GridCells.Adaptive sets columns based on minimum item size, adapting to screen width.

2. Step 2: Match requirement to code

   LazyVerticalGrid(columns = GridCells.Adaptive(120.dp)) { /* images */ } uses GridCells.Adaptive(120.dp), which fits the requirement of minimum 120.dp per item and adapts columns.

3. Final Answer:

   LazyVerticalGrid(columns = GridCells.Adaptive(120.dp)) { /* images */ } -> Option D

4. Quick Check:

   Adaptive columns use minimum size = A [OK]

Hint: Use GridCells.Adaptive(minSize) for responsive columns [OK]

Common Mistakes:

• Using Fixed with pixel count instead of dp
• Confusing number of columns with minimum size
• Using Adaptive with integer instead of dp