Initial Commit

As of now, only the illuminance value itself is beeing updated, no calculations are done.

app/src/main/java/eu/wa5p/lightmeter/LightmeterState.kt

@@ -0,0 +1,8 @@
+package eu.wa5p.lightmeter
+
+data class LightmeterState(
+    var illuminance: Double, // lux
+    var aperture: Double, // f-stops
+    var iso: Int,
+    var shutterSpeed: Double // s
+)

app/src/main/java/eu/wa5p/lightmeter/MainActivity.kt

@@ -0,0 +1,171 @@
+package eu.wa5p.lightmeter
+
+import android.content.Context
+import android.hardware.Sensor
+import android.hardware.SensorEvent
+import android.hardware.SensorEventListener
+import android.hardware.SensorManager
+import android.os.Bundle
+import android.util.Log
+import androidx.activity.ComponentActivity
+import androidx.activity.compose.setContent
+import androidx.activity.enableEdgeToEdge
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.MutableState
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.text.style.TextAlign
+import androidx.compose.ui.tooling.preview.Preview
+import androidx.compose.ui.unit.dp
+import eu.wa5p.lightmeter.ui.theme.LightMeterTheme
+
+const val TAG: String = "lightmeter MainActivity"
+
+class MainActivity : ComponentActivity(), SensorEventListener {
+    private lateinit var sensorManager: SensorManager
+    private var illuminanceSensor: Sensor? = null
+    private var lightmeterState = mutableStateOf(
+        LightmeterState(
+            illuminance = 0.0,
+            aperture = 1.8,
+            iso = 100,
+            shutterSpeed = 0.01
+        )
+    )
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        enableEdgeToEdge()
+        setContent {
+            LightMeterTheme {
+                LightmeterHomeScreen(state = lightmeterState )
+            }
+        }
+
+        // Get an instance of the sensor service, and use that to get an instance of
+        // a particular sensor.
+        sensorManager = getSystemService(Context.SENSOR_SERVICE) as SensorManager
+        illuminanceSensor = sensorManager.getDefaultSensor(Sensor.TYPE_LIGHT)
+    }
+
+    override fun onSensorChanged(event: SensorEvent?) {
+        event?.values?.let {
+            for (v in it) {
+                Log.d(TAG, "sensor changed: $v lux")
+                lightmeterState.value = lightmeterState.value.copy(illuminance = v.toDouble())
+            }
+        }
+    }
+
+    override fun onAccuracyChanged(sensor: Sensor?, accuracy: Int) {
+        Log.d(TAG, "accuracy changed: sensor: ${sensor?.name}. accuracy: $accuracy")
+    }
+
+    override fun onResume() {
+        // Register a listener for the sensor.
+        super.onResume()
+        sensorManager.registerListener(this, illuminanceSensor, SensorManager.SENSOR_DELAY_NORMAL)
+    }
+
+    override fun onPause() {
+        // Be sure to unregister the sensor when the activity pauses.
+        super.onPause()
+        sensorManager.unregisterListener(this)
+    }
+}
+
+@Composable
+fun LightmeterListItem(
+    label: String,
+    value: String,
+    unit: String
+) {
+    Row(modifier = Modifier.padding(bottom = 8.dp)) {
+        Text(
+            modifier = Modifier.weight(0.4f).padding(all = 8.dp),
+            text = label
+        )
+        Text(
+            modifier = Modifier.weight(0.4f).padding(all = 8.dp),
+            textAlign = TextAlign.Right,
+            text = value
+        )
+        Text(
+            modifier = Modifier.weight(0.2f).padding(all = 8.dp),
+            text = unit
+        )
+    }
+}
+
+@Preview(showBackground = true)
+@Composable
+fun LightmeterListItemPreview() {
+    LightMeterTheme {
+        LightmeterListItem(
+            label = "Illuminance",
+            value = "1234",
+            unit = "lux"
+        )
+    }
+}
+
+@Composable
+fun LightmeterHomeScreen(state: MutableState<LightmeterState>) {
+    Box(
+        modifier = Modifier.fillMaxSize(),
+        contentAlignment = Alignment.Center
+    ) {
+        Column(
+            verticalArrangement = Arrangement.Center
+        ) {
+            LightmeterListItem(
+                label = "Illuminance",
+                value = "%.2f".format(state.value.illuminance),
+                unit = "lux"
+            )
+            LightmeterListItem(
+                label = "ISO",
+                value = state.value.iso.toString(),
+                unit = ""
+            )
+            LightmeterListItem(
+                label = "Aperture",
+                value = "%.2f".format(state.value.aperture),
+                unit = "f"
+            )
+            LightmeterListItem(
+                label = "Shutter Speed",
+                value = "%.2f".format(state.value.shutterSpeed),
+                unit = "s"
+            )
+        }
+    }
+}
+
+@Preview(showBackground = true)
+@Composable
+fun LightmeterHomeScreenPreview() {
+    LightMeterTheme {
+        LightmeterHomeScreen(
+            state = remember {
+                mutableStateOf(
+                    LightmeterState(
+                        illuminance = 0.0,
+                        aperture = 1.8,
+                        iso = 100,
+                        shutterSpeed = 0.01
+                    )
+                )
+            }
+        )
+    }
+}

app/src/main/java/eu/wa5p/lightmeter/ui/theme/Color.kt

@@ -0,0 +1,11 @@
+package eu.wa5p.lightmeter.ui.theme
+
+import androidx.compose.ui.graphics.Color
+
+val Purple80 = Color(0xFFD0BCFF)
+val PurpleGrey80 = Color(0xFFCCC2DC)
+val Pink80 = Color(0xFFEFB8C8)
+
+val Purple40 = Color(0xFF6650a4)
+val PurpleGrey40 = Color(0xFF625b71)
+val Pink40 = Color(0xFF7D5260)

app/src/main/java/eu/wa5p/lightmeter/ui/theme/Theme.kt

@@ -0,0 +1,58 @@
+package eu.wa5p.lightmeter.ui.theme
+
+import android.app.Activity
+import android.os.Build
+import androidx.compose.foundation.isSystemInDarkTheme
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.darkColorScheme
+import androidx.compose.material3.dynamicDarkColorScheme
+import androidx.compose.material3.dynamicLightColorScheme
+import androidx.compose.material3.lightColorScheme
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.platform.LocalContext
+
+private val DarkColorScheme = darkColorScheme(
+    primary = Purple80,
+    secondary = PurpleGrey80,
+    tertiary = Pink80
+)
+
+private val LightColorScheme = lightColorScheme(
+    primary = Purple40,
+    secondary = PurpleGrey40,
+    tertiary = Pink40
+
+    /* Other default colors to override
+    background = Color(0xFFFFFBFE),
+    surface = Color(0xFFFFFBFE),
+    onPrimary = Color.White,
+    onSecondary = Color.White,
+    onTertiary = Color.White,
+    onBackground = Color(0xFF1C1B1F),
+    onSurface = Color(0xFF1C1B1F),
+    */
+)
+
+@Composable
+fun LightMeterTheme(
+    darkTheme: Boolean = isSystemInDarkTheme(),
+    // Dynamic color is available on Android 12+
+    dynamicColor: Boolean = true,
+    content: @Composable () -> Unit
+) {
+    val colorScheme = when {
+        dynamicColor && Build.VERSION.SDK_INT >= Build.VERSION_CODES.S -> {
+            val context = LocalContext.current
+            if (darkTheme) dynamicDarkColorScheme(context) else dynamicLightColorScheme(context)
+        }
+
+        darkTheme -> DarkColorScheme
+        else -> LightColorScheme
+    }
+
+    MaterialTheme(
+        colorScheme = colorScheme,
+        typography = Typography,
+        content = content
+    )
+}

app/src/main/java/eu/wa5p/lightmeter/ui/theme/Type.kt

@@ -0,0 +1,34 @@
+package eu.wa5p.lightmeter.ui.theme
+
+import androidx.compose.material3.Typography
+import androidx.compose.ui.text.TextStyle
+import androidx.compose.ui.text.font.FontFamily
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.unit.sp
+
+// Set of Material typography styles to start with
+val Typography = Typography(
+    bodyLarge = TextStyle(
+        fontFamily = FontFamily.Default,
+        fontWeight = FontWeight.Normal,
+        fontSize = 16.sp,
+        lineHeight = 24.sp,
+        letterSpacing = 0.5.sp
+    )
+    /* Other default text styles to override
+    titleLarge = TextStyle(
+        fontFamily = FontFamily.Default,
+        fontWeight = FontWeight.Normal,
+        fontSize = 22.sp,
+        lineHeight = 28.sp,
+        letterSpacing = 0.sp
+    ),
+    labelSmall = TextStyle(
+        fontFamily = FontFamily.Default,
+        fontWeight = FontWeight.Medium,
+        fontSize = 11.sp,
+        lineHeight = 16.sp,
+        letterSpacing = 0.5.sp
+    )
+    */
+)