PDF generation: change to a BottomSheet, button to "open" the saved PDF

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

@@ -14,9 +14,11 @@
  */
 package org.mydomain.myscan
 
+import android.content.ActivityNotFoundException
 import android.content.Intent
 import android.content.pm.PackageManager
 import android.media.MediaScannerConnection
+import android.net.Uri
 import android.os.Bundle
 import android.os.Environment
 import android.util.Log
@@ -28,6 +30,7 @@ import androidx.activity.viewModels
 import androidx.compose.runtime.getValue
 import androidx.core.content.FileProvider
 import androidx.core.net.toFile
+import androidx.core.net.toUri
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
@@ -40,6 +43,8 @@ import org.mydomain.myscan.view.DocumentScreen
 import org.opencv.android.OpenCVLoader
 import java.io.File
 
+private const val PDF_MIME_TYPE = "application/pdf"
+
 class MainActivity : ComponentActivity() {
 
     override fun onCreate(savedInstanceState: Bundle?) {
@@ -71,9 +76,10 @@ class MainActivity : ComponentActivity() {
                                 startGeneration = viewModel::startPdfGeneration,
                                 cancelGeneration = viewModel::cancelPdfGeneration,
                                 setFilename = viewModel::setFilename,
-                                generatedPdfFlow = viewModel.generatedPdf,
+                                uiStateFlow = viewModel.pdfUiState,
                                 sharePdf = { sharePdf(viewModel.getFinalPdf()) },
-                                savePdf = { savePdf(viewModel.getFinalPdf()) },
+                                savePdf = { savePdf(viewModel.getFinalPdf(), viewModel) },
+                                openPdf = { openPdf(viewModel.pdfUiState.value.savedFileUri) }
                             ),
                             onStartNew = {
                                 viewModel.startNewDocument()
@@ -93,7 +99,7 @@ class MainActivity : ComponentActivity() {
         val authority = "${applicationContext.packageName}.fileprovider"
         val fileUri = FileProvider.getUriForFile(this, authority, file)
         val shareIntent = Intent(Intent.ACTION_SEND).apply {
-            type = "application/pdf"
+            type = PDF_MIME_TYPE
             putExtra(Intent.EXTRA_STREAM, fileUri)
             addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION)
         }
@@ -107,7 +113,7 @@ class MainActivity : ComponentActivity() {
         startActivity(chooser)
     }
 
-    private fun savePdf(generatedPdf: GeneratedPdf?) {
+    private fun savePdf(generatedPdf: GeneratedPdf?, viewModel: MainViewModel) {
         if (generatedPdf == null)
             return
         val appScope = CoroutineScope(Dispatchers.IO)
@@ -123,17 +129,13 @@ class MainActivity : ComponentActivity() {
                 val targetFile = File(downloadsDir, generatedFile.name)
                 // TODO Handle case where the target file already exists (choose a unique name)
                 generatedFile.copyTo(targetFile)
-
+                viewModel.markFileSaved(targetFile.toUri())
-                withContext(Dispatchers.Main) {
-                    // TODO Display a link to the file
-                    Toast.makeText(context, "Saved PDF in Downloads", Toast.LENGTH_SHORT).show()
-                }
 
                 suspendCancellableCoroutine { continuation ->
                     MediaScannerConnection.scanFile(
                         context,
                         arrayOf(targetFile.absolutePath),
-                        arrayOf("application/pdf")
+                        arrayOf(PDF_MIME_TYPE)
                     ) { _, _ -> continuation.resume(Unit) {} }
                 }
             } catch (e: Exception) {
@@ -145,6 +147,24 @@ class MainActivity : ComponentActivity() {
         }
     }
 
+    private fun openPdf(fileUri: Uri?) {
+        if (fileUri == null) return
+        val uri = FileProvider.getUriForFile(
+            this,
+            "${applicationContext.packageName}.fileprovider",
+            fileUri.toFile()
+        )
+        val openIntent = Intent(Intent.ACTION_VIEW).apply {
+            setDataAndType(uri, PDF_MIME_TYPE)
+            addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION)
+        }
+        try {
+            startActivity(Intent.createChooser(openIntent, "Open PDF"))
+        } catch (_: ActivityNotFoundException) {
+            Toast.makeText(this, "No app found to open PDF", Toast.LENGTH_SHORT).show()
+        }
+    }
+
     private fun initLibraries() {
         com.tom_roush.pdfbox.android.PDFBoxResourceLoader.init(applicationContext)
 

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

@@ -18,6 +18,7 @@ import android.content.Context
 import android.graphics.Bitmap
 import android.graphics.BitmapFactory
 import android.net.Uri
+import android.util.Log
 import androidx.camera.core.ImageProxy
 import androidx.core.net.toFile
 import androidx.core.net.toUri
@@ -32,8 +33,10 @@ import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.asStateFlow
 import kotlinx.coroutines.flow.filterNotNull
 import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.flow.update
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.withContext
+import org.mydomain.myscan.ui.PdfGenerationUiState
 import java.io.ByteArrayOutputStream
 import java.io.File
 import java.io.FileOutputStream
@@ -208,7 +211,9 @@ class MainViewModel(
     }
 
     private val _generatedPdf = MutableStateFlow<GeneratedPdf?>(null)
-    val generatedPdf: StateFlow<GeneratedPdf?> = _generatedPdf
+
+    private val _pdfUiState = MutableStateFlow(PdfGenerationUiState())
+    val pdfUiState: StateFlow<PdfGenerationUiState> = _pdfUiState.asStateFlow()
 
     private var generationJob: Job? = null
     private var desiredFilename: String = ""
@@ -218,29 +223,56 @@ class MainViewModel(
     }
 
     fun startPdfGeneration() {
-        if (_generatedPdf.value != null) return
+        val currentState = _pdfUiState.value
+        if (currentState.isGenerating || currentState.generatedPdf != null) return
+
+        _pdfUiState.update { it.copy(isGenerating = true, errorMessage = null) }
+
         generationJob = viewModelScope.launch {
+            try {
                 val result = generatePdf()
-            _generatedPdf.value = result
+                _pdfUiState.update {
+                    it.copy(
+                        isGenerating = false,
+                        generatedPdf = result
+                    )
+                }
+            } catch (e: Exception) {
+                Log.e("MyScan", "PDF generation failed", e)
+                _pdfUiState.update {
+                    it.copy(
+                        isGenerating = false,
+                        errorMessage = "PDF generation failed"
+                    )
+                }
+            }
         }
     }
 
     fun cancelPdfGeneration() {
         generationJob?.cancel()
-        _generatedPdf.value = null
+        _pdfUiState.value = PdfGenerationUiState()
     }
 
     fun getFinalPdf(): GeneratedPdf? {
-        val temp = _generatedPdf.value ?: return null
+        val tempPdf = _pdfUiState.value.generatedPdf ?: return null
-        val tempFile = temp.uri.toFile()
+        val tempFile = tempPdf.uri.toFile()
         val newFile = File(tempFile.parentFile, desiredFilename)
         if (tempFile.absolutePath != newFile.absolutePath) {
             if (newFile.exists()) newFile.delete()
             val success = tempFile.renameTo(newFile)
             if (!success) return null
-            _generatedPdf.value = GeneratedPdf(uri = newFile.toUri(), temp.sizeInBytes, temp.pageCount)
+            _pdfUiState.update {
+                it.copy(generatedPdf = GeneratedPdf(
+                    uri = newFile.toUri(), tempPdf.sizeInBytes, tempPdf.pageCount)
+                )
             }
-        return _generatedPdf.value
+        }
+        return _pdfUiState.value.generatedPdf
+    }
+
+    fun markFileSaved(uri: Uri) {
+        _pdfUiState.update { it.copy(savedFileUri = uri) }
     }
 }
 
@@ -250,11 +282,13 @@ data class GeneratedPdf(
     val pageCount: Int,
 )
 
+// TODO Move somewhere else: ViewModel should not depend on that
 data class PdfGenerationActions(
     val startGeneration: () -> Unit,
     val cancelGeneration: () -> Unit,
     val setFilename: (String) -> Unit,
-    val generatedPdfFlow: StateFlow<GeneratedPdf?>,
+    val uiStateFlow: StateFlow<PdfGenerationUiState>,// TODO is it ok to have that here?
     val sharePdf: () -> Unit,
-    val savePdf: () -> Unit
+    val savePdf: () -> Unit,
+    val openPdf: () -> Unit,
 )

app/src/main/java/org/mydomain/myscan/ui/UiState.kt

@@ -0,0 +1,26 @@
+/*
+ * Copyright 2025 Pierre-Yves Nicolas
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation, either version 3 of the License, or (at your option)
+ * any later version.
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ * You should have received a copy of the GNU General Public License along with
+ * this program. If not, see <https://www.gnu.org/licenses/>.
+ */
+package org.mydomain.myscan.ui
+
+import android.net.Uri
+import org.mydomain.myscan.GeneratedPdf
+
+data class PdfGenerationUiState(
+    val isGenerating: Boolean = false,
+    val generatedPdf: GeneratedPdf? = null,
+    val desiredFilename: String = "",
+    val savedFileUri: Uri? = null,
+    val errorMessage: String? = null
+)

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

@@ -67,6 +67,7 @@ import kotlinx.coroutines.flow.MutableStateFlow
 import net.engawapg.lib.zoomable.rememberZoomState
 import net.engawapg.lib.zoomable.zoomable
 import org.mydomain.myscan.PdfGenerationActions
+import org.mydomain.myscan.ui.PdfGenerationUiState
 import org.mydomain.myscan.ui.theme.MyScanTheme
 
 @OptIn(ExperimentalMaterial3Api::class)
@@ -292,8 +293,8 @@ fun DocumentScreenPreview() {
             toCameraScreen = {},
             pdfActions = PdfGenerationActions(
                 {}, {}, {},
-                MutableStateFlow(null),
+                MutableStateFlow(PdfGenerationUiState()),
-                {}, {}),
+                {}, {}, {}),
             onStartNew = {},
             onDeleteImage = { _ -> {} }
         )

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

@@ -0,0 +1,215 @@
+/*
+ * Copyright 2025 Pierre-Yves Nicolas
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation, either version 3 of the License, or (at your option)
+ * any later version.
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ * You should have received a copy of the GNU General Public License along with
+ * this program. If not, see <https://www.gnu.org/licenses/>.
+ */
+package org.mydomain.myscan.view
+
+import android.content.Context
+import android.text.format.Formatter
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.width
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.automirrored.filled.OpenInNew
+import androidx.compose.material3.Button
+import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.material3.Icon
+import androidx.compose.material3.LinearProgressIndicator
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.ModalBottomSheet
+import androidx.compose.material3.OutlinedButton
+import androidx.compose.material3.OutlinedTextField
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.tooling.preview.Preview
+import androidx.compose.ui.unit.dp
+import androidx.core.net.toUri
+import org.mydomain.myscan.GeneratedPdf
+import org.mydomain.myscan.PdfGenerationActions
+import org.mydomain.myscan.ui.PdfGenerationUiState
+import org.mydomain.myscan.ui.theme.MyScanTheme
+import java.text.SimpleDateFormat
+import java.util.Date
+import java.util.Locale
+
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+fun PdfGenerationDialogWrapper(
+    onDismiss: () -> Unit,
+    pdfActions: PdfGenerationActions,
+    modifier: Modifier = Modifier,
+) {
+    var filename by remember { mutableStateOf(defaultFilename()) }
+    val uiState by pdfActions.uiStateFlow.collectAsState()
+    LaunchedEffect(Unit) {
+        pdfActions.setFilename(filename)
+        pdfActions.startGeneration()
+    }
+
+    ModalBottomSheet(
+        onDismissRequest = onDismiss,
+        modifier = modifier
+    ) {
+        PdfGenerationBottomSheet(
+            filename = filename,
+            onFilenameChange = {
+                filename = it
+                pdfActions.setFilename(it)
+            },
+            uiState = uiState,
+            onDismiss = {
+                pdfActions.cancelGeneration()
+                onDismiss()
+            },
+            onShare = { pdfActions.sharePdf() },
+            onSave = { pdfActions.savePdf() },
+            onOpen = { pdfActions.openPdf() },
+        )
+    }
+}
+
+// TODO Handle error in PDF generation
+@Composable
+fun PdfGenerationBottomSheet(
+    filename: String,
+    onFilenameChange: (String) -> Unit,
+    uiState: PdfGenerationUiState,
+    onDismiss: () -> Unit,
+    onShare: () -> Unit,
+    onSave: () -> Unit,
+    onOpen: () -> Unit,
+) {
+    Column(
+        modifier = Modifier
+            .fillMaxWidth()
+            .padding(24.dp)
+    ) {
+        Text("Generate PDF", style = MaterialTheme.typography.headlineSmall)
+
+        Spacer(Modifier.height(16.dp))
+
+        OutlinedTextField(
+            value = filename,
+            onValueChange = onFilenameChange,
+            label = { Text("Filename") },
+            singleLine = true,
+            modifier = Modifier.fillMaxWidth()
+        )
+
+        Spacer(Modifier.height(8.dp))
+
+        val pdf = uiState.generatedPdf
+        if (uiState.isGenerating) {
+            LinearProgressIndicator(modifier = Modifier.fillMaxWidth())
+        } else if (pdf != null) {
+            val context = LocalContext.current
+            Text("${pdf.pageCount} pages · ${formatFileSize(pdf.sizeInBytes, context)}")
+        }
+
+        Spacer(Modifier.height(24.dp))
+
+        Row(
+            horizontalArrangement = Arrangement.spacedBy(8.dp),
+            modifier = Modifier.fillMaxWidth()
+        ) {
+            OutlinedButton(
+                onClick = onDismiss,
+                modifier = Modifier.weight(1f)
+            ) { Text("Close") }
+
+            OutlinedButton(
+                onClick = onShare,
+                enabled = pdf != null,
+                modifier = Modifier.weight(1f)
+            ) { Text("Share") }
+
+            OutlinedButton(
+                onClick = onSave,
+                enabled = pdf != null,
+                modifier = Modifier.weight(1f)
+            ) { Text("Save") }
+        }
+        if (uiState.savedFileUri != null) {
+            Spacer(modifier = Modifier.height(16.dp))
+            Text(
+                text = "PDF saved to Downloads",
+                style = MaterialTheme.typography.bodyMedium
+            )
+            Spacer(modifier = Modifier.height(8.dp))
+            Button(onClick = onOpen) {
+                Icon(Icons.AutoMirrored.Filled.OpenInNew, contentDescription = null)
+                Spacer(Modifier.width(8.dp))
+                Text("Open")
+            }
+        }
+
+    }
+}
+
+fun defaultFilename(): String {
+    val timestamp = SimpleDateFormat("yyyyMMdd_HHmmss", Locale.getDefault()).format(Date())
+    return "scan_$timestamp.pdf"
+}
+
+fun formatFileSize(sizeInBytes: Long?, context: Context): String {
+    return if (sizeInBytes == null) "Unknown size"
+    else Formatter.formatShortFileSize(context, sizeInBytes)
+}
+
+@Preview(showBackground = true)
+@Composable
+fun PreviewPdfGenerationDialogDuringGeneration() {
+    MyScanTheme {
+        PdfGenerationBottomSheet(
+            filename = "scan_20250702_174042.pdf",
+            uiState = PdfGenerationUiState(isGenerating = true),
+            onFilenameChange = {},
+            onDismiss = {},
+            onShare = {},
+            onSave = {},
+            onOpen = {},
+        )
+    }
+}
+
+@Preview(showBackground = true)
+@Composable
+fun PreviewPdfGenerationDialogAfterGeneration() {
+    MyScanTheme {
+        PdfGenerationBottomSheet(
+            filename = "scan_20250702_174042.pdf",
+            uiState = PdfGenerationUiState(
+                isGenerating = false,
+                generatedPdf = GeneratedPdf("file://fake.pdf".toUri(), 42897L, 3)
+            ),
+            onFilenameChange = {},
+            onDismiss = {},
+            onShare = {},
+            onSave = {},
+            onOpen = {},
+        )
+    }
+}

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

@@ -1,167 +0,0 @@
-/*
- * Copyright 2025 Pierre-Yves Nicolas
- *
- * This program is free software: you can redistribute it and/or modify it
- * under the terms of the GNU General Public License as published by the Free
- * Software Foundation, either version 3 of the License, or (at your option)
- * any later version.
- * This program is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
- * more details.
- * You should have received a copy of the GNU General Public License along with
- * this program. If not, see <https://www.gnu.org/licenses/>.
- */
-package org.mydomain.myscan.view
-
-import android.content.Context
-import android.text.format.Formatter
-import androidx.compose.foundation.layout.Arrangement
-import androidx.compose.foundation.layout.Column
-import androidx.compose.foundation.layout.Row
-import androidx.compose.foundation.layout.Spacer
-import androidx.compose.foundation.layout.fillMaxWidth
-import androidx.compose.foundation.layout.size
-import androidx.compose.foundation.layout.width
-import androidx.compose.material3.AlertDialog
-import androidx.compose.material3.CircularProgressIndicator
-import androidx.compose.material3.OutlinedTextField
-import androidx.compose.material3.Text
-import androidx.compose.material3.TextButton
-import androidx.compose.runtime.Composable
-import androidx.compose.runtime.LaunchedEffect
-import androidx.compose.runtime.collectAsState
-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.platform.LocalContext
-import androidx.compose.ui.tooling.preview.Preview
-import androidx.compose.ui.unit.dp
-import androidx.core.net.toUri
-import org.mydomain.myscan.GeneratedPdf
-import org.mydomain.myscan.PdfGenerationActions
-import org.mydomain.myscan.ui.theme.MyScanTheme
-import java.text.SimpleDateFormat
-import java.util.Date
-import java.util.Locale
-
-@Composable
-fun PdfGenerationDialogWrapper(
-    onDismiss: () -> Unit,
-    pdfActions: PdfGenerationActions,
-) {
-    var filename by remember { mutableStateOf(defaultFilename()) }
-    val generatedPdf by pdfActions.generatedPdfFlow.collectAsState()
-    LaunchedEffect(Unit) {
-        pdfActions.setFilename(filename)
-        pdfActions.startGeneration()
-    }
-
-    PdfGenerationDialog(
-        filename = filename,
-        onFilenameChange = {
-            filename = it
-            pdfActions.setFilename(it)
-        },
-        pdf = generatedPdf,
-        onDismiss = {
-            pdfActions.cancelGeneration()
-            onDismiss()
-        },
-        onShare = { pdfActions.sharePdf() },
-        onSave = { pdfActions.savePdf() },
-    )
-}
-
-// TODO Handle error in PDF generation
-@Composable
-fun PdfGenerationDialog(
-    filename: String,
-    onFilenameChange: (String) -> Unit,
-    pdf: GeneratedPdf?,
-    onDismiss: () -> Unit,
-    onShare: () -> Unit,
-    onSave: () -> Unit,
-) {
-    AlertDialog(
-        onDismissRequest = onDismiss,
-        title = { Text("Generate PDF") },
-        text = {
-            Column(verticalArrangement = Arrangement.spacedBy(8.dp)) {
-                OutlinedTextField(
-                    value = filename,
-                    onValueChange = onFilenameChange,
-                    label = { Text("Filename") },
-                    modifier = Modifier.fillMaxWidth()
-                )
-                if (pdf == null) {
-                    Row(verticalAlignment = Alignment.CenterVertically) {
-                        CircularProgressIndicator(
-                            modifier = Modifier.size(24.dp),
-                            strokeWidth = 2.dp
-                        )
-                        Spacer(Modifier.width(8.dp))
-                        Text("Generating PDF…")
-                    }
-                } else {
-                    val context = LocalContext.current
-                    Text("${pdf.pageCount} pages – ${formatFileSize(pdf.sizeInBytes, context)}")
-                }
-            }
-        },
-        confirmButton = {
-            if (pdf != null) {
-                Row(horizontalArrangement = Arrangement.spacedBy(8.dp)) {
-                    TextButton(onClick = onShare) { Text("Share") }
-                    TextButton(onClick = onSave) { Text("Save") }
-                }
-            }
-        },
-        dismissButton = {
-            TextButton(onClick = onDismiss) { Text("Close") }
-        }
-    )
-}
-
-fun defaultFilename(): String {
-    val timestamp = SimpleDateFormat("yyyyMMdd_HHmmss", Locale.getDefault()).format(Date())
-    return "scan_$timestamp.pdf"
-}
-
-fun formatFileSize(sizeInBytes: Long?, context: Context): String {
-    return if (sizeInBytes == null) "Unknown size"
-    else Formatter.formatShortFileSize(context, sizeInBytes)
-}
-
-@Preview
-@Composable
-fun PreviewPdfGenerationDialogDuringGeneration() {
-    MyScanTheme {
-        PdfGenerationDialog(
-            filename = "scan_20250702_174042.pdf",
-            pdf = null,
-            onFilenameChange = {},
-            onDismiss = {},
-            onShare = {},
-            onSave = {},
-        )
-    }
-}
-
-@Preview
-@Composable
-fun PreviewPdfGenerationDialogAfterGeneration() {
-    MyScanTheme {
-        PdfGenerationDialog(
-            filename = "scan_20250702_174042.pdf",
-            pdf = GeneratedPdf("file://fake.pdf".toUri(), 42897L, 3),
-            onFilenameChange = {},
-            onDismiss = {},
-            onShare = {},
-            onSave = {},
-        )
-    }
-}

app/src/main/res/xml/file_paths.xml

@@ -3,4 +3,7 @@
     <cache-path
         name="pdfs"
         path="pdfs/" />
+    <external-path
+        name="external_files"
+        path="." />
 </paths>