feat: Implement Answer Feedback Banner

This commit introduces an `AnswerFeedbackBanner` composable that displays whether a selected answer is correct or wrong. It's integrated into the `Toolbar` section of the `QuizScreen`.

Key changes:

- **UI Layer (`ui:quiz` module):**
    - Created `AnswerFeedbackBanner.kt` composable:
        - Displays "Correct" or "Wrong" text with a green or red background respectively.
        - Uses `Surface` for elevation and `zIndex` to appear above other elements.
    - In `QuizScreen.kt`:
        - Modified the `toolbar` item to include a `Box` that layers the `Toolbar` and the new `AnswerFeedbackBanner`.
        - The `AnswerFeedbackBanner` is shown when `uiState.isAnswerCorrect` is not null.
    - In `QuizScreenViewModel.kt`:
        - Added `isAnswerCorrect: Boolean?` to `ScreenUiState.Success`.
        - Calculated `isAnswerCorrect` based on the selected choice and the correct answer for the current question.
- **Resources (`ui:quiz` module):**
    - Added new string resources for "Correct" and "Wrong" in `strings.xml`.

ui/quiz/src/main/kotlin/dev/adriankuta/kahootquiz/ui/quiz/QuizScreen.kt

@@ -32,6 +32,7 @@ import dev.adriankuta.kahootquiz.core.designsystem.KahootQuizTheme
 import dev.adriankuta.kahootquiz.domain.models.Choice
 import dev.adriankuta.kahootquiz.domain.models.Question
 import dev.adriankuta.kahootquiz.ui.quiz.components.Choices
+import dev.adriankuta.kahootquiz.ui.quiz.components.AnswerFeedbackBanner
 import dev.adriankuta.kahootquiz.ui.quiz.components.QuestionContent
 import dev.adriankuta.kahootquiz.ui.quiz.components.TimerBar
 import dev.adriankuta.kahootquiz.ui.quiz.components.Toolbar
@@ -115,16 +116,26 @@ private fun QuizScreenSuccess(
 
 private fun LazyListScope.toolbar(
     uiState: ScreenUiState.Success,
+    modifier: Modifier = Modifier,
 ) {
     item(key = "toolbar") {
-        Toolbar(
-            modifier = Modifier
-                .fillMaxWidth()
-                .height(72.dp)
-                .padding(8.dp),
-            currentQuestionIndex = uiState.currentQuestionIndex,
-            totalQuestions = uiState.totalQuestions,
-        )
+        Box(
+            modifier = modifier
+                .height(72.dp),
+        ) {
+            Toolbar(
+                modifier = Modifier
+                    .fillMaxSize()
+                    .padding(8.dp),
+                currentQuestionIndex = uiState.currentQuestionIndex,
+                totalQuestions = uiState.totalQuestions,
+            )
+            uiState.isAnswerCorrect?.let { isCorrect ->
+                AnswerFeedbackBanner(
+                    isCorrect = isCorrect,
+                )
+            }
+        }
     }
 }
 

ui/quiz/src/main/kotlin/dev/adriankuta/kahootquiz/ui/quiz/QuizScreenViewModel.kt

@@ -61,6 +61,9 @@ class QuizScreenViewModel @Inject constructor(
             QuizUiState.Loading -> ScreenUiState.Loading
             is QuizUiState.Success -> {
                 val currentQuestion = quizState.quiz.questions.getOrNull(currentQuestionIndex)
+                val isAnswerCorrect = selectedChoiceIndex?.let { idx ->
+                    currentQuestion?.choices?.getOrNull(idx)?.correct == true
+                }
 
                 ScreenUiState.Success(
                     currentQuestion = currentQuestion,
@@ -71,6 +74,7 @@ class QuizScreenViewModel @Inject constructor(
                         remainingTimeSeconds = remainingTimeSeconds,
                         totalTimeSeconds = currentQuestion?.time?.inWholeSeconds?.toInt() ?: 0,
                     ),
+                    isAnswerCorrect = isAnswerCorrect,
                 )
             }
         }
@@ -148,6 +152,7 @@ sealed interface ScreenUiState {
         val currentQuestionIndex: Int = 0,
         val totalQuestions: Int = 0,
         val timerState: TimerState = TimerState(),
+        val isAnswerCorrect: Boolean? = null,
     ) : ScreenUiState
 }
 

ui/quiz/src/main/kotlin/dev/adriankuta/kahootquiz/ui/quiz/components/CorrectnessBanner.kt

@@ -0,0 +1,40 @@
+package dev.adriankuta.kahootquiz.ui.quiz.components
+
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.text.style.TextAlign
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.zIndex
+import dev.adriankuta.kahootquiz.core.designsystem.Green
+import dev.adriankuta.kahootquiz.core.designsystem.Red
+import dev.adriankuta.kahootquiz.ui.quiz.R
+
+@Composable
+fun AnswerFeedbackBanner(
+    isCorrect: Boolean,
+    modifier: Modifier = Modifier,
+) {
+    Surface(
+        modifier = modifier
+            .fillMaxSize()
+            .zIndex(10f),
+        shadowElevation = 8.dp,
+        color = if (isCorrect) Green else Red,
+        contentColor = Color.White,
+    ) {
+        Box {
+            Text(
+                text = stringResource(if (isCorrect) R.string.correct else R.string.wrong),
+                textAlign = TextAlign.Center,
+                modifier = Modifier.align(Alignment.Center),
+            )
+        }
+    }
+}

ui/quiz/src/main/res/values/strings.xml

@@ -2,4 +2,6 @@
 <resources>
     <string name="quiz">Quiz</string>
     <string name="continue_text">Continue</string>
+    <string name="correct">Correct</string>
+    <string name="wrong">Wrong</string>
 </resources>