MainActivity.kt

/*
 * Copyright (C) 2020 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.example.diceroller

import android.os.Bundle
import android.widget.Button
import android.widget.ImageView
import androidx.appcompat.app.AppCompatActivity

/**
 * This activity allows the user to roll a dice and view the result
 * on the screen.
 */
class MainActivity : AppCompatActivity() {

    /**
     * This method is called when the Activity is created.
     */
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        // Find the Button in the layout
        val rollButton: Button = findViewById(R.id.button)

        // Set a click listener on the button to roll the dice when the user taps the button
        rollButton.setOnClickListener { rollDice() }

        // Do a dice roll when the app starts
        rollDice()
    }

    /**
     * Roll the dice and update the screen with the result.
     */
    private fun rollDice() {
        // Create new Dice object with 6 sides and roll it
        val dice = Dice(6)
        val diceRoll = dice.roll()

        // Find the ImageView in the layout
        val diceImage: ImageView = findViewById(R.id.imageView)
        
        // Update the ImageView with the correct drawable resource ID
        diceImage.setImageResource(

            // Determine which drawable resource ID to use based on the dice roll
            when (diceRoll) {
                1 -> R.drawable.dice_1
                2 -> R.drawable.dice_2
                3 -> R.drawable.dice_3
                4 -> R.drawable.dice_4
                5 -> R.drawable.dice_5
                else -> R.drawable.dice_6
            }

        )

        // Update the content description
        diceImage.contentDescription = diceRoll.toString()
    }
}

/**
 * Dice with a fixed number of sides.
 */
class Dice(private val numSides: Int) {

    /**
     * Do a random dice roll and return the result.
     */
    fun roll(): Int {
        return (1..numSides).random()
    }
}