Sudoku Puzzle Image with Jetpack Compose

 To create a Sudoku puzzle image programmatically in Kotlin, you can use libraries such as Android Canvas or Jetpack Compose. Below is an example using Jetpack Compose, which is a modern toolkit for building Android UI.

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Sudoku Puzzle Image with Jetpack Compose

This code draws a 9x9 Sudoku grid with some numbers pre-filled.

import android.os.Bundle
import androidx.activity.ComponentActivity
import androidx.activity.compose.setContent
import androidx.compose.foundation.Canvas
import androidx.compose.foundation.layout.*
import androidx.compose.runtime.Composable
import androidx.compose.ui.Modifier
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.graphics.Paint
import androidx.compose.ui.text.TextStyle
import androidx.compose.ui.unit.dp
import androidx.compose.ui.unit.sp
import androidx.compose.foundation.text.BasicText

class SudokuActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent {
            SudokuGrid()
        }
    }
}

@Composable
fun SudokuGrid() {
    val puzzle = arrayOf(
        charArrayOf('5', '3', '.', '.', '7', '.', '.', '.', '.'),
        charArrayOf('6', '.', '.', '1', '9', '5', '.', '.', '.'),
        charArrayOf('.', '9', '8', '.', '.', '.', '.', '6', '.'),
        charArrayOf('8', '.', '.', '.', '6', '.', '.', '.', '3'),
        charArrayOf('4', '.', '.', '8', '.', '3', '.', '.', '1'),
        charArrayOf('7', '.', '.', '.', '2', '.', '.', '.', '6'),
        charArrayOf('.', '6', '.', '.', '.', '.', '2', '8', '.'),
        charArrayOf('.', '.', '.', '4', '1', '9', '.', '.', '5'),
        charArrayOf('.', '.', '.', '.', '8', '.', '.', '7', '9')
    )

    Box(Modifier.fillMaxSize().padding(16.dp)) {
        Canvas(modifier = Modifier.fillMaxSize()) {
            val gridSize = size.width
            val cellSize = gridSize / 9f

            val paint = Paint().apply { color = Color.Black }

            // Draw the grid lines
            for (i in 0..9) {
                val lineWidth = if (i % 3 == 0) 6f else 2f
                drawLine(
                    start = androidx.compose.ui.geometry.Offset(i * cellSize, 0f),
                    end = androidx.compose.ui.geometry.Offset(i * cellSize, gridSize),
                    paint.apply { strokeWidth = lineWidth }
                )
                drawLine(
                    start = androidx.compose.ui.geometry.Offset(0f, i * cellSize),
                    end = androidx.compose.ui.geometry.Offset(gridSize, i * cellSize),
                    paint.apply { strokeWidth = lineWidth }
                )
            }
        }

        // Fill the grid with numbers
        for (row in puzzle.indices) {
            for (col in puzzle[row].indices) {
                val number = puzzle[row][col]
                if (number != '.') {
                    BasicText(
                        text = number.toString(),
                        style = TextStyle(color = Color.Black, fontSize = 20.sp),
                        modifier = Modifier
                            .offset(x = (col * (size / 9f)).dp, y = (row * (size / 9f)).dp)
                    )
                }
            }
        }
    }
}

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How It Works:

1. Grid Drawing:
   The Canvas composable is used to draw the Sudoku grid. Thicker lines are drawn every three cells to demarcate the 3x3 sub-grids.

2. Number Placement:
   A nested loop iterates over the puzzle array and places numbers using BasicText at the correct cell coordinates.

3. Customizations:

   • Grid Size: Automatically adapts to the screen.
   • Font Size and Style: Easily customizable for better visuals.

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Output:

• A 9x9 Sudoku grid is displayed, with the given puzzle pre-filled.
• The grid uses clear lines and neatly places numbers in their respective cells.

This example provides a dynamic, scalable, and modern approach for creating Sudoku images directly in an Android app.