Avoid a possible crash when deleting an image

app/src/main/java/org/mydomain/myscan/ImageRepository.kt

@@ -39,12 +39,12 @@ class ImageRepository(appFilesDir: File) {
         fileNames.add(fileName)
     }
 
-    fun getContent(id: String): ByteArray {
+    fun getContent(id: String): ByteArray? {
         if (fileNames.contains(id)) {
             val file = File(scanDir, id)
             return file.readBytes()
         }
-        throw IllegalArgumentException("No image for id: $id")
+        return null
     }
 
     fun delete(id: String) {

app/src/main/java/org/mydomain/myscan/MainViewModel.kt

@@ -137,14 +137,15 @@ class MainViewModel(
 
     fun pageCount(): Int = pageIds.value.size
 
-    fun getBitmap(id: String): Bitmap {
+    fun getBitmap(id: String): Bitmap? {
         val bytes = imageRepository.getContent(id)
-        return BitmapFactory.decodeByteArray(bytes, 0, bytes.size)
+        return bytes?.let { BitmapFactory.decodeByteArray(it, 0, it.size) }
     }
 
     fun createPdf(outputStream: OutputStream) {
         val jpegs = imageRepository.imageIds().asSequence()
             .map { id -> imageRepository.getContent(id) }
+            .filterNotNull()
         writePdfFromJpegs(jpegs, outputStream)
     }
 }

app/src/main/java/org/mydomain/myscan/view/DocumentScreen.kt

@@ -74,7 +74,7 @@ import org.mydomain.myscan.ui.theme.MyScanTheme
 @Composable
 fun DocumentScreen(
     pageIds: List<String>,
-    imageLoader: (String) -> Bitmap,
+    imageLoader: (String) -> Bitmap?,
     toCameraScreen: () -> Unit,
     onSavePressed: () -> Unit,
     onSharePressed: () -> Unit,
@@ -135,7 +135,7 @@ fun DocumentScreen(
 @Composable
 private fun DocumentPreview(
     pageIds: List<String>,
-    imageLoader: (String) -> Bitmap,
+    imageLoader: (String) -> Bitmap?,
     currentPageIndex: MutableIntState,
     onDeleteImage: (String) -> Unit,
     padding: PaddingValues,
@@ -151,21 +151,24 @@ private fun DocumentPreview(
             modifier = Modifier.fillMaxSize()
         ) {
             val bitmap = imageLoader(imageId)
-            val imageBitmap = bitmap.asImageBitmap()
+            if (bitmap != null) {
-            val zoomState = rememberZoomState(
+                val imageBitmap = bitmap.asImageBitmap()
-                contentSize = Size(bitmap.width.toFloat(), bitmap.height.toFloat()))
+                val zoomState = rememberZoomState(
+                    contentSize = Size(bitmap.width.toFloat(), bitmap.height.toFloat())
+                )
 
-            LaunchedEffect(imageId) {
+                LaunchedEffect(imageId) {
-                zoomState.reset()
+                    zoomState.reset()
+                }
+                Image(
+                    bitmap = imageBitmap,
+                    contentDescription = null,
+                    modifier = Modifier
+                        .padding(4.dp)
+                        .align(Alignment.Center)
+                        .zoomable(zoomState)
+                )
             }
-            Image(
-                bitmap = imageBitmap,
-                contentDescription = null,
-                modifier = Modifier
-                    .padding(4.dp)
-                    .align(Alignment.Center)
-                    .zoomable(zoomState)
-            )
             SmallFloatingActionButton(
                 onClick = { onDeleteImage(imageId) },
                 modifier = Modifier.align(Alignment.TopEnd).padding(4.dp)
@@ -186,7 +189,7 @@ private fun DocumentPreview(
 @Composable
 private fun PageList(
     pageIds: List<String>,
-    imageLoader: (String) -> Bitmap,
+    imageLoader: (String) -> Bitmap?,
     currentPageIndex: MutableState<Int>,
     toCameraScreen: () -> Unit
 ) {
@@ -202,22 +205,26 @@ private fun PageList(
         ) {
             itemsIndexed (pageIds) { index, id ->
                 // TODO Use small images rather than big ones
-                val bitmap = imageLoader(id).asImageBitmap()
+                val image = imageLoader(id)
-                val isSelected = index == currentPageIndex.value
+                if (image != null) {
-                val borderColor = if (isSelected) MaterialTheme.colorScheme.primary else Color.Transparent
+                    val bitmap = image.asImageBitmap()
-                val modifier =
+                    val isSelected = index == currentPageIndex.value
-                    if (bitmap.height > bitmap.width)
+                    val borderColor =
-                        Modifier.height(120.dp)
+                        if (isSelected) MaterialTheme.colorScheme.primary else Color.Transparent
-                    else
+                    val modifier =
-                        Modifier.width(120.dp)
+                        if (bitmap.height > bitmap.width)
-                Image(
+                            Modifier.height(120.dp)
-                    bitmap = bitmap,
+                        else
-                    contentDescription = null,
+                            Modifier.width(120.dp)
-                    modifier = modifier
+                    Image(
-                        .padding(4.dp)
+                        bitmap = bitmap,
-                        .border(2.dp, borderColor)
+                        contentDescription = null,
-                        .clickable { currentPageIndex.value = index }
+                        modifier = modifier
-                )
+                            .padding(4.dp)
+                            .border(2.dp, borderColor)
+                            .clickable { currentPageIndex.value = index }
+                    )
+                }
             }
         }
         SmallFloatingActionButton(

app/src/test/java/org/mydomain/myscan/ImageRepositoryTest.kt

@@ -14,7 +14,6 @@
  */
 package org.mydomain.myscan
 
-import org.assertj.core.api.Assertions
 import org.assertj.core.api.Assertions.assertThat
 import org.junit.Rule
 import org.junit.Test
@@ -73,10 +72,9 @@ class ImageRepositoryTest {
     }
 
     @Test
-    fun `should throw on invalid id`() {
+    fun `should return null on invalid id`() {
         val repo = repo()
         assertThat(repo.imageIds()).isEmpty()
-        Assertions.assertThatThrownBy { repo.getContent("x") }
+        assertThat(repo.getContent("x")).isNull()
-            .isInstanceOf(IllegalArgumentException::class.java)
     }
 }