Tugas 11 - Membuat ViewModel dan State Pada Compose Dengan Aplikasi Unscramble

Pada tugas kali ini, saya akan membuat aplikasi tebak kata berdasarkan kata yang diacak. Sebagai starter project, Anda dapat melakukan clone github berikut (github clone -b starter https://github.com/google-developer-training/basic-android-kotlin-compose-training-unscramble.git). 

Selanjutnya, lakukan beberapa tambahan kode program berikut.

build.gradle.kts (Module :app)

dependencies {
    implementation(platform("androidx.compose:compose-bom:2023.08.00"))
    implementation("androidx.activity:activity-compose:1.8.0")
    implementation("androidx.compose.material3:material3")
    implementation("androidx.compose.ui:ui")
    implementation("androidx.compose.ui:ui-graphics")
    implementation("androidx.compose.ui:ui-tooling-preview")
    implementation("androidx.core:core-ktx:1.12.0")
    implementation("androidx.lifecycle:lifecycle-runtime-ktx:2.6.2")
    implementation("androidx.lifecycle:lifecycle-viewmodel-compose:2.6.2")

    debugImplementation("androidx.compose.ui:ui-test-manifest")
    debugImplementation("androidx.compose.ui:ui-tooling")
}

Tambahkan file class Kotlin di dalam folder ui dengan nama GameViewModel. Tambahkan kode berikut.

/*
 * Copyright (C) 2023 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
 *
 *     https://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.unscramble.ui

import androidx.compose.runtime.getValue
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.setValue
import androidx.lifecycle.ViewModel
import com.example.unscramble.data.MAX_NO_OF_WORDS
import com.example.unscramble.data.SCORE_INCREASE
import com.example.unscramble.data.allWords
import kotlinx.coroutines.flow.MutableStateFlow
import kotlinx.coroutines.flow.StateFlow
import kotlinx.coroutines.flow.asStateFlow
import kotlinx.coroutines.flow.update

/**
 * ViewModel containing the app data and methods to process the data
 */
class GameViewModel : ViewModel() {

    // Game UI state
    private val _uiState = MutableStateFlow(GameUiState())
    val uiState: StateFlow<GameUiState> = _uiState.asStateFlow()

    var userGuess by mutableStateOf("")
        private set

    // Set of words used in the game
    private var usedWords: MutableSet<String> = mutableSetOf()
    private lateinit var currentWord: String

    init {
        resetGame()
    }

    /*
     * Re-initializes the game data to restart the game.
     */
    fun resetGame() {
        usedWords.clear()
        _uiState.value = GameUiState(currentScrambledWord = pickRandomWordAndShuffle())
    }

    /*
     * Update the user's guess
     */
    fun updateUserGuess(guessedWord: String){
        userGuess = guessedWord
    }

    /*
     * Checks if the user's guess is correct.
     * Increases the score accordingly.
     */
    fun checkUserGuess() {
        if (userGuess.equals(currentWord, ignoreCase = true)) {
            // User's guess is correct, increase the score
            // and call updateGameState() to prepare the game for next round
            val updatedScore = _uiState.value.score.plus(SCORE_INCREASE)
            updateGameState(updatedScore)
        } else {
            // User's guess is wrong, show an error
            _uiState.update { currentState ->
                currentState.copy(isGuessedWordWrong = true)
            }
        }
        // Reset user guess
        updateUserGuess("")
    }

    /*
     * Skip to next word
     */
    fun skipWord() {
        updateGameState(_uiState.value.score)
        // Reset user guess
        updateUserGuess("")
    }

    /*
     * Picks a new currentWord and currentScrambledWord and updates UiState according to
     * current game state.
     */
    private fun updateGameState(updatedScore: Int) {
        if (usedWords.size == MAX_NO_OF_WORDS){
            //Last round in the game, update isGameOver to true, don't pick a new word
            _uiState.update { currentState ->
                currentState.copy(
                    isGuessedWordWrong = false,
                    score = updatedScore,
                    isGameOver = true
                )
            }
        } else{
            // Normal round in the game
            _uiState.update { currentState ->
                currentState.copy(
                    isGuessedWordWrong = false,
                    currentScrambledWord = pickRandomWordAndShuffle(),
                    currentWordCount = currentState.currentWordCount.inc(),
                    score = updatedScore
                )
            }
        }
    }

    private fun shuffleCurrentWord(word: String): String {
        val tempWord = word.toCharArray()
        // Scramble the word
        tempWord.shuffle()
        while (String(tempWord) == word) {
            tempWord.shuffle()
        }
        return String(tempWord)
    }

    private fun pickRandomWordAndShuffle(): String {
        // Continue picking up a new random word until you get one that hasn't been used before
        currentWord = allWords.random()
        return if (usedWords.contains(currentWord)) {
            pickRandomWordAndShuffle()
        } else {
            usedWords.add(currentWord)
            shuffleCurrentWord(currentWord)
        }
    }
}

Tambahkan file class Kotlin di dalam folder ui dengan nama GameUiState. Tambahkan kode berikut.

/*
 * Copyright (C) 2023 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
 *
 *     https://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.unscramble.ui

/**
 * Data class that represents the game UI state
 */
data class GameUiState(
    val currentScrambledWord: String = "",
    val currentWordCount: Int = 1,
    val score: Int = 0,
    val isGuessedWordWrong: Boolean = false,
    val isGameOver: Boolean = false
)

GameScreen.kt

/*
 * Copyright (C) 2023 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
 *
 *     https://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.unscramble.ui

import android.app.Activity
import androidx.compose.foundation.background
import androidx.compose.foundation.layout.Arrangement
import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.fillMaxWidth
import androidx.compose.foundation.layout.padding
import androidx.compose.foundation.layout.safeDrawingPadding
import androidx.compose.foundation.layout.statusBarsPadding
import androidx.compose.foundation.layout.wrapContentHeight
import androidx.compose.foundation.rememberScrollState
import androidx.compose.foundation.text.KeyboardActions
import androidx.compose.foundation.text.KeyboardOptions
import androidx.compose.foundation.verticalScroll
import androidx.compose.material3.AlertDialog
import androidx.compose.material3.Button
import androidx.compose.material3.Card
import androidx.compose.material3.CardDefaults
import androidx.compose.material3.MaterialTheme.colorScheme
import androidx.compose.material3.MaterialTheme.shapes
import androidx.compose.material3.MaterialTheme.typography
import androidx.compose.material3.OutlinedButton
import androidx.compose.material3.OutlinedTextField
import androidx.compose.material3.Text
import androidx.compose.material3.TextButton
import androidx.compose.material3.TextFieldDefaults
import androidx.compose.runtime.Composable
import androidx.compose.runtime.collectAsState
import androidx.compose.runtime.getValue
import androidx.compose.ui.Alignment
import androidx.compose.ui.Modifier
import androidx.compose.ui.draw.clip
import androidx.compose.ui.platform.LocalContext
import androidx.compose.ui.res.dimensionResource
import androidx.compose.ui.res.stringResource
import androidx.compose.ui.text.input.ImeAction
import androidx.compose.ui.text.style.TextAlign
import androidx.compose.ui.tooling.preview.Preview
import androidx.compose.ui.unit.dp
import androidx.compose.ui.unit.sp
import androidx.lifecycle.viewmodel.compose.viewModel
import com.example.unscramble.R
import com.example.unscramble.ui.theme.UnscrambleTheme

@Composable
fun GameScreen(gameViewModel: GameViewModel = viewModel()) {
    val gameUiState by gameViewModel.uiState.collectAsState()
    val mediumPadding = dimensionResource(R.dimen.padding_medium)

    Column(
        modifier = Modifier
            .statusBarsPadding()
            .verticalScroll(rememberScrollState())
            .safeDrawingPadding()
            .padding(mediumPadding),
        verticalArrangement = Arrangement.Center,
        horizontalAlignment = Alignment.CenterHorizontally
    ) {

        Text(
            text = stringResource(R.string.app_name),
            style = typography.titleLarge,
        )
        GameLayout(
            onUserGuessChanged = { gameViewModel.updateUserGuess(it) },
            wordCount = gameUiState.currentWordCount,
            userGuess = gameViewModel.userGuess,
            onKeyboardDone = { gameViewModel.checkUserGuess() },
            currentScrambledWord = gameUiState.currentScrambledWord,
            isGuessWrong = gameUiState.isGuessedWordWrong,
            modifier = Modifier
                .fillMaxWidth()
                .wrapContentHeight()
                .padding(mediumPadding)
        )
        Column(
            modifier = Modifier
                .fillMaxWidth()
                .padding(mediumPadding),
            verticalArrangement = Arrangement.spacedBy(mediumPadding),
            horizontalAlignment = Alignment.CenterHorizontally
        ) {

            Button(
                modifier = Modifier.fillMaxWidth(),
                onClick = { gameViewModel.checkUserGuess() }
            ) {
                Text(
                    text = stringResource(R.string.submit),
                    fontSize = 16.sp
                )
            }

            OutlinedButton(
                onClick = { gameViewModel.skipWord() },
                modifier = Modifier.fillMaxWidth()
            ) {
                Text(
                    text = stringResource(R.string.skip),
                    fontSize = 16.sp
                )
            }
        }

        GameStatus(score = gameUiState.score, modifier = Modifier.padding(20.dp))

        if (gameUiState.isGameOver) {
            FinalScoreDialog(
                score = gameUiState.score,
                onPlayAgain = { gameViewModel.resetGame() }
            )
        }
    }
}

@Composable
fun GameStatus(score: Int, modifier: Modifier = Modifier) {
    Card(
        modifier = modifier
    ) {
        Text(
            text = stringResource(R.string.score, score),
            style = typography.headlineMedium,
            modifier = Modifier.padding(8.dp)
        )

    }
}

@Composable
fun GameLayout(
    currentScrambledWord: String,
    wordCount: Int,
    isGuessWrong: Boolean,
    userGuess: String,
    onUserGuessChanged: (String) -> Unit,
    onKeyboardDone: () -> Unit,
    modifier: Modifier = Modifier
) {
    val mediumPadding = dimensionResource(R.dimen.padding_medium)

    Card(
        modifier = modifier,
        elevation = CardDefaults.cardElevation(defaultElevation = 5.dp)
    ) {
        Column(
            verticalArrangement = Arrangement.spacedBy(mediumPadding),
            horizontalAlignment = Alignment.CenterHorizontally,
            modifier = Modifier.padding(mediumPadding)
        ) {
            Text(
                modifier = Modifier
                    .clip(shapes.medium)
                    .background(colorScheme.surfaceTint)
                    .padding(horizontal = 10.dp, vertical = 4.dp)
                    .align(alignment = Alignment.End),
                text = stringResource(R.string.word_count, wordCount),
                style = typography.titleMedium,
                color = colorScheme.onPrimary
            )
            Text(
                text = currentScrambledWord,
                style = typography.displayMedium
            )
            Text(
                text = stringResource(R.string.instructions),
                textAlign = TextAlign.Center,
                style = typography.titleMedium
            )
            OutlinedTextField(
                value = userGuess,
                singleLine = true,
                shape = shapes.large,
                modifier = Modifier.fillMaxWidth(),
                colors = TextFieldDefaults.colors(
                    focusedContainerColor = colorScheme.surface,
                    unfocusedContainerColor = colorScheme.surface,
                    disabledContainerColor = colorScheme.surface,
                ),
                onValueChange = onUserGuessChanged,
                label = {
                    if (isGuessWrong) {
                        Text(stringResource(R.string.wrong_guess))
                    } else {
                        Text(stringResource(R.string.enter_your_word))
                    }
                },
                isError = isGuessWrong,
                keyboardOptions = KeyboardOptions.Default.copy(
                    imeAction = ImeAction.Done
                ),
                keyboardActions = KeyboardActions(
                    onDone = { onKeyboardDone() }
                )
            )
        }
    }
}

/*
 * Creates and shows an AlertDialog with final score.
 */
@Composable
private fun FinalScoreDialog(
    score: Int,
    onPlayAgain: () -> Unit,
    modifier: Modifier = Modifier
) {
    val activity = (LocalContext.current as Activity)

    AlertDialog(
        onDismissRequest = {
            // Dismiss the dialog when the user clicks outside the dialog or on the back
            // button. If you want to disable that functionality, simply use an empty
            // onCloseRequest.
        },
        title = { Text(text = stringResource(R.string.congratulations)) },
        text = { Text(text = stringResource(R.string.you_scored, score)) },
        modifier = modifier,
        dismissButton = {
            TextButton(
                onClick = {
                    activity.finish()
                }
            ) {
                Text(text = stringResource(R.string.exit))
            }
        },
        confirmButton = {
            TextButton(onClick = onPlayAgain) {
                Text(text = stringResource(R.string.play_again))
            }
        }
    )
}

@Preview(showBackground = true)
@Composable
fun GameScreenPreview() {
    UnscrambleTheme {
        GameScreen()
    }
}

strings.xml

<!--
  ~ Copyright (C) 2023 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
  ~
  ~     https://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.
  -->

<resources>
    <string name="app_name">Unscramble</string>
    <string name="instructions">Unscramble the word using all the letters.</string>
    <string name="skip">Skip</string>
    <string name="submit">Submit</string>
    <string name="score">Score: %d</string>
    <string name="word_count">%d/10</string>
    <string name="enter_your_word">Enter your word</string>
    <string name="congratulations">Congratulations!</string>
    <string name="you_scored">"You scored: %d"</string>
    <string name="exit">Exit</string>
    <string name="play_again">Play Again</string>
    <string name="wrong_guess">Wrong Guess!</string>
</resources>

Hasil dari aplikasi tersebut kurang lebih adalah sebagai berikut.