fix: 添加 DebugLogger 日志库，修复启动图标缺失及多处崩溃

app/src/main/java/com/example/androidruler/RulerApplication.kt

@@ -1,5 +1,11 @@
 package com.example.androidruler
 
 import android.app.Application
+import com.example.androidruler.util.DebugLogger
 
-class RulerApplication : Application()
+class RulerApplication : Application() {
+    override fun onCreate() {
+        super.onCreate()
+        DebugLogger.init(this)
+    }
+}

app/src/main/java/com/example/androidruler/theme/Theme.kt

@@ -25,7 +25,8 @@ fun AndroidRulerTheme(
     val view = LocalView.current
     if (!view.isInEditMode) {
         SideEffect {
-            val window = (view.context as Activity).window
+            val activity = view.context as? Activity ?: return@SideEffect
+            val window = activity.window
             window.statusBarColor = colorScheme.primary.toArgb()
             WindowCompat.getInsetsController(window, view).isAppearanceLightStatusBars = !darkTheme
         }

app/src/main/java/com/example/androidruler/ui/RulerCanvas.kt

@@ -31,6 +31,8 @@ fun RulerCanvas(
     val textMeasurer = rememberTextMeasurer()
     val isPortrait = LocalConfiguration.current.screenHeightDp > LocalConfiguration.current.screenWidthDp
 
+    if (pixelPerCm <= 0f) return
+
     val scrollModifier = if (isPortrait) {
         Modifier
             .fillMaxWidth()

app/src/main/java/com/example/androidruler/ui/RulerScreen.kt

@@ -10,6 +10,10 @@ import androidx.compose.material3.Icon
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.Color
@@ -26,8 +30,24 @@ fun RulerScreen(
     val context = LocalContext.current
 
     LaunchedEffect(Unit) {
-        val dpi = context.resources.displayMetrics.xdpi
-        viewModel.calculatePixelPerCm(dpi)
+        try {
+            val dpi = context.resources.displayMetrics.xdpi
+            viewModel.calculatePixelPerCm(dpi)
+        } catch (e: Exception) {
+            android.util.Log.e("RulerScreen", "Failed to calculate pixel per cm", e)
+        }
+    }
+
+    // guard: don't render ruler until pixelPerCm is ready
+    if (viewModel.pixelPerCm <= 0f) {
+        Box(modifier = modifier.fillMaxSize()) {
+            Text(
+                text = "初始化中...",
+                modifier = Modifier.align(Alignment.Center),
+                fontSize = 16.sp
+            )
+        }
+        return
     }
 
     val measuredDistance = viewModel.measuredDistance

app/src/main/java/com/example/androidruler/ui/photo/CameraCapture.kt

@@ -26,8 +26,8 @@ import androidx.compose.ui.platform.LocalLifecycleOwner
 import androidx.compose.ui.unit.dp
 import androidx.compose.ui.viewinterop.AndroidView
 import androidx.core.content.ContextCompat
+import com.example.androidruler.util.DebugLogger
 import java.nio.ByteBuffer
-import java.util.concurrent.Executors
 
 @Composable
 fun CameraCapture(
@@ -55,20 +55,29 @@ fun CameraCapture(
 
         Button(
             onClick = {
-                cameraController.takePicture(
-                    ContextCompat.getMainExecutor(context),
-                    object : ImageCapture.OnImageCapturedCallback() {
-                        override fun onCaptureSuccess(image: ImageProxy) {
-                            val bitmap = imageProxyToBitmap(image)
-                            image.close()
-                            bitmap?.let { onPhotoTaken(it) }
-                        }
+                try {
+                    cameraController.takePicture(
+                        ContextCompat.getMainExecutor(context),
+                        object : ImageCapture.OnImageCapturedCallback() {
+                            override fun onCaptureSuccess(image: ImageProxy) {
+                                try {
+                                    val bitmap = imageProxyToBitmap(image)
+                                    bitmap?.let { onPhotoTaken(it) }
+                                } catch (e: Exception) {
+                                    DebugLogger.e("CameraCapture", "Failed to process captured image", e)
+                                } finally {
+                                    image.close()
+                                }
+                            }
 
-                        override fun onError(exception: ImageCaptureException) {
-                            exception.printStackTrace()
+                            override fun onError(exception: ImageCaptureException) {
+                                DebugLogger.e("CameraCapture", "Capture error", exception)
+                            }
                         }
-                    }
-                )
+                    )
+                } catch (e: Exception) {
+                    DebugLogger.e("CameraCapture", "takePicture failed", e)
+                }
             },
             modifier = Modifier
                 .align(Alignment.BottomCenter)
@@ -83,13 +92,25 @@ fun CameraCapture(
 }
 
 private fun imageProxyToBitmap(image: ImageProxy): Bitmap? {
-    val buffer: ByteBuffer = image.planes[0].buffer
-    val bytes = ByteArray(buffer.remaining())
-    buffer.get(bytes)
+    return try {
+        if (image.planes.isEmpty()) {
+            DebugLogger.w("CameraCapture", "ImageProxy has no planes")
+            return null
+        }
+        val buffer: ByteBuffer = image.planes[0].buffer
+        val bytes = ByteArray(buffer.remaining())
+        buffer.get(bytes)
 
-    val bitmap = BitmapFactory.decodeByteArray(bytes, 0, bytes.size) ?: return null
-    val matrix = Matrix().apply {
-        postRotate(image.imageInfo.rotationDegrees.toFloat())
+        val bitmap = BitmapFactory.decodeByteArray(bytes, 0, bytes.size) ?: run {
+            DebugLogger.w("CameraCapture", "Failed to decode image bytes")
+            return null
+        }
+        val matrix = Matrix().apply {
+            postRotate(image.imageInfo.rotationDegrees.toFloat())
+        }
+        Bitmap.createBitmap(bitmap, 0, 0, bitmap.width, bitmap.height, matrix, true)
+    } catch (e: Exception) {
+        DebugLogger.e("CameraCapture", "imageProxyToBitmap failed", e)
+        null
     }
-    return Bitmap.createBitmap(bitmap, 0, 0, bitmap.width, bitmap.height, matrix, true)
 }

app/src/main/java/com/example/androidruler/util/DebugLogger.kt

@@ -0,0 +1,115 @@
+package com.example.androidruler.util
+
+import android.content.Context
+import android.os.Build
+import android.os.Environment
+import java.io.File
+import java.io.FileWriter
+import java.io.PrintWriter
+import java.io.StringWriter
+import java.text.SimpleDateFormat
+import java.util.Date
+import java.util.Locale
+import kotlin.system.exitProcess
+
+object DebugLogger {
+
+    private var logFile: File? = null
+    private val dateFormat = SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS", Locale.US)
+    private var initialized = false
+
+    fun init(context: Context) {
+        if (initialized) return
+        initialized = true
+
+        try {
+            val logDir = File(context.getExternalFilesDir(null), "logs")
+            logDir.mkdirs()
+            logFile = File(logDir, "ruler_debug_${System.currentTimeMillis()}.log")
+            logFile?.createNewFile()
+
+            d("DebugLogger", "Logger initialized. SDK=${Build.VERSION.SDK_INT}, Model=${Build.MODEL}, Manufacturer=${Build.MANUFACTURER}")
+
+            // global crash handler
+            val defaultHandler = Thread.getDefaultUncaughtExceptionHandler()
+            Thread.setDefaultUncaughtExceptionHandler { thread, throwable ->
+                e("CrashHandler", "Uncaught exception in thread '${thread.name}'", throwable)
+                flush()
+                // pass to default handler
+                defaultHandler?.uncaughtException(thread, throwable)
+                // if no default handler, kill process
+                exitProcess(1)
+            }
+        } catch (e: Exception) {
+            android.util.Log.e("DebugLogger", "Failed to initialize logger", e)
+        }
+    }
+
+    @JvmStatic
+    fun d(tag: String, message: String) {
+        log("DEBUG", tag, message, null)
+    }
+
+    @JvmStatic
+    fun i(tag: String, message: String) {
+        log("INFO", tag, message, null)
+    }
+
+    @JvmStatic
+    fun w(tag: String, message: String, throwable: Throwable? = null) {
+        log("WARN", tag, message, throwable)
+    }
+
+    @JvmStatic
+    fun e(tag: String, message: String, throwable: Throwable? = null) {
+        log("ERROR", tag, message, throwable)
+    }
+
+    private fun log(level: String, tag: String, message: String, throwable: Throwable?) {
+        val timestamp = synchronized(dateFormat) { dateFormat.format(Date()) }
+        val sb = StringBuilder()
+        sb.append("$timestamp [$level] $tag: $message")
+
+        if (throwable != null) {
+            sb.append("\n")
+            val sw = StringWriter()
+            throwable.printStackTrace(PrintWriter(sw))
+            sb.append(sw.toString())
+        }
+
+        val line = sb.toString()
+
+        // write to android logcat
+        when (level) {
+            "DEBUG" -> android.util.Log.d(tag, line)
+            "INFO" -> android.util.Log.i(tag, line)
+            "WARN" -> android.util.Log.w(tag, line)
+            "ERROR" -> android.util.Log.e(tag, line)
+        }
+
+        // write to file
+        try {
+            logFile?.let { file ->
+                FileWriter(file, true).use { writer ->
+                    writer.appendLine(line)
+                }
+            }
+        } catch (_: Exception) {
+            // best effort
+        }
+    }
+
+    fun flush() {
+        // file writes are already flushed via use{}
+    }
+
+    fun getLogFilePath(): String? = logFile?.absolutePath
+
+    fun getRecentLogs(maxLines: Int = 200): String {
+        return try {
+            logFile?.readLines()?.takeLast(maxLines)?.joinToString("\n") ?: "No logs available"
+        } catch (e: Exception) {
+            "Failed to read logs: ${e.message}"
+        }
+    }
+}

app/src/main/java/com/example/androidruler/viewmodel/RulerViewModel.kt

@@ -9,6 +9,7 @@ import androidx.compose.runtime.setValue
 import androidx.lifecycle.AndroidViewModel
 import androidx.lifecycle.viewModelScope
 import com.example.androidruler.data.SettingsRepository
+import com.example.androidruler.util.DebugLogger
 import kotlinx.coroutines.flow.first
 import kotlinx.coroutines.launch
 import kotlin.math.abs
@@ -36,10 +37,15 @@ class RulerViewModel(application: Application) : AndroidViewModel(application) {
 
     init {
         viewModelScope.launch {
-            cmCorrectionFactor = repo.correctionFactor.first()
-            isCalibrated = repo.isCalibrated.first()
-            defaultOrientation = repo.defaultOrientation.first()
-            overlayRulerLength = repo.defaultRulerLength.first()
+            try {
+                cmCorrectionFactor = repo.correctionFactor.first()
+                isCalibrated = repo.isCalibrated.first()
+                defaultOrientation = repo.defaultOrientation.first()
+                overlayRulerLength = repo.defaultRulerLength.first()
+                DebugLogger.i("RulerViewModel", "Settings loaded: correctionFactor=$cmCorrectionFactor, calibrated=$isCalibrated")
+            } catch (e: Exception) {
+                DebugLogger.e("RulerViewModel", "Failed to load settings, using defaults", e)
+            }
         }
     }
 
@@ -77,13 +83,18 @@ class RulerViewModel(application: Application) : AndroidViewModel(application) {
         correctionFactor: Float
     ) {
         viewModelScope.launch {
-            defaultOrientation = orientation
-            overlayRulerLength = rulerLength
-            cmCorrectionFactor = correctionFactor
-            repo.setDefaultOrientation(orientation)
-            repo.setDefaultRulerLength(rulerLength)
-            repo.setCorrectionFactor(correctionFactor)
-            isCalibrated = true
+            try {
+                defaultOrientation = orientation
+                overlayRulerLength = rulerLength
+                cmCorrectionFactor = correctionFactor
+                repo.setDefaultOrientation(orientation)
+                repo.setDefaultRulerLength(rulerLength)
+                repo.setCorrectionFactor(correctionFactor)
+                isCalibrated = true
+                DebugLogger.i("RulerViewModel", "Settings saved: orientation=$orientation, length=$rulerLength, factor=$correctionFactor")
+            } catch (e: Exception) {
+                DebugLogger.e("RulerViewModel", "Failed to save settings", e)
+            }
         }
     }