Use derived state for contrastColor in BrightDisplayActivity

app/src/main/kotlin/com/simplemobiletools/flashlight/activities/BrightDisplayActivity.kt

@@ -7,12 +7,15 @@ import android.view.WindowManager
 import androidx.activity.ComponentActivity
 import androidx.activity.compose.setContent
 import androidx.activity.viewModels
+import androidx.compose.runtime.derivedStateOf
 import androidx.compose.runtime.getValue
+import androidx.compose.runtime.remember
 import androidx.lifecycle.AndroidViewModel
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import com.simplemobiletools.commons.compose.extensions.enableEdgeToEdgeSimple
 import com.simplemobiletools.commons.compose.theme.AppThemeSurface
 import com.simplemobiletools.commons.dialogs.ColorPickerDialog
+import com.simplemobiletools.commons.extensions.getContrastColor
 import com.simplemobiletools.commons.extensions.getFormattedDuration
 import com.simplemobiletools.flashlight.extensions.config
 import com.simplemobiletools.flashlight.helpers.stopSleepTimerCountDown
@@ -41,11 +44,13 @@ class BrightDisplayActivity : ComponentActivity() {
         setContent {
             AppThemeSurface {
                 val backgroundColor by viewModel.backgroundColor.collectAsStateWithLifecycle()
+                val contrastColor by remember { derivedStateOf { backgroundColor.getContrastColor() } }
                 val timerVisible by viewModel.timerVisible.collectAsStateWithLifecycle()
                 val timerText by viewModel.timerText.collectAsStateWithLifecycle()
 
                 BrightDisplayScreen(
                     backgroundColor = backgroundColor,
+                    contrastColor = contrastColor,
                     onChangeColorPress = {
                         ColorPickerDialog(this, config.brightDisplayColor, true, currentColorCallback = {
                             viewModel.updateBackgroundColor(it)

app/src/main/kotlin/com/simplemobiletools/flashlight/screens/BrightDisplayScreen.kt

@@ -28,6 +28,7 @@ import com.simplemobiletools.flashlight.views.SleepTimer
 @Composable
 internal fun BrightDisplayScreen(
     backgroundColor: Int,
+    contrastColor: Int,
     timerText: String,
     timerVisible: Boolean,
     onChangeColorPress: () -> Unit,
@@ -44,14 +45,14 @@ internal fun BrightDisplayScreen(
                 .align(Alignment.Center)
                 .border(
                     width = 1.dp,
-                    color = Color(backgroundColor.getContrastColor()),
+                    color = Color(contrastColor),
                     shape = MaterialTheme.shapes.extraLarge
                 ),
             onClick = onChangeColorPress
         ) {
             Text(
                 text = stringResource(id = R.string.change_color),
-                color = Color(backgroundColor.getContrastColor())
+                color = Color(contrastColor)
             )
         }
 
@@ -77,6 +78,7 @@ private fun BrightDisplayScreenPreview() {
     AppThemeSurface {
         BrightDisplayScreen(
             backgroundColor = MaterialTheme.colorScheme.background.toArgb(),
+            contrastColor = MaterialTheme.colorScheme.background.toArgb().getContrastColor(),
             timerText = "00:00",
             timerVisible = true,
             onChangeColorPress = {},