Save PDF and share it

app/src/main/AndroidManifest.xml

@@ -28,6 +28,15 @@
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
         </activity>
+        <provider
+            android:name="androidx.core.content.FileProvider"
+            android:authorities="${applicationId}.fileprovider"
+            android:exported="false"
+            android:grantUriPermissions="true">
+            <meta-data
+                android:name="android.support.FILE_PROVIDER_PATHS"
+                android:resource="@xml/file_paths" />
+        </provider>
     </application>
 
 </manifest>

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

@@ -1,7 +1,11 @@
 package org.mydomain.myscan
 
+import android.content.Context
+import android.content.Intent
+import android.graphics.Bitmap
 import android.os.Bundle
 import android.util.Log
+import android.widget.Toast
 import androidx.activity.ComponentActivity
 import androidx.activity.compose.setContent
 import androidx.activity.enableEdgeToEdge
@@ -17,13 +21,16 @@ import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.tooling.preview.Preview
 import androidx.compose.ui.unit.dp
+import androidx.core.content.FileProvider
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import org.mydomain.myscan.ui.theme.MyScanTheme
 import org.mydomain.myscan.view.CameraScreen
 import org.mydomain.myscan.view.PagePreviewScreen
 import org.opencv.android.OpenCVLoader
+import java.io.File
 
 class MainActivity : ComponentActivity() {
 
@@ -37,6 +44,7 @@ class MainActivity : ComponentActivity() {
             val currentScreen by viewModel.currentScreen.collectAsState()
             // TODO should uiState own currentScreen?
             val uiState by viewModel.uiState.collectAsStateWithLifecycle()
+            val context = LocalContext.current
             MyScanTheme {
                 Scaffold { innerPadding ->
                     Column {
@@ -51,7 +59,8 @@ class MainActivity : ComponentActivity() {
                                 PagePreviewScreen (
                                     image = screen.image,
                                     isProcessing = screen.isProcessing,
-                                    onBackPressed = { viewModel.navigateTo(Screen.Camera) }
+                                    onBackPressed = { viewModel.navigateTo(Screen.Camera) },
+                                    onSavePressed = createPdfAndShare(context)
                                 )
                             }
                         }
@@ -61,6 +70,27 @@ class MainActivity : ComponentActivity() {
         }
     }
 
+    private fun createPdfAndShare(context: Context): (Bitmap) -> Unit = { bitmap ->
+        val outputDir = File(cacheDir, "pdfs").apply { mkdirs() }
+        val outputFile = File(outputDir, "scan_${System.currentTimeMillis()}.pdf")
+        val success = createPdfFromBitmaps(listOf(bitmap), outputFile)
+        if (success) {
+            val uri = FileProvider.getUriForFile(
+                context,
+                "${applicationContext.packageName}.fileprovider",
+                outputFile
+            )
+            val shareIntent = Intent(Intent.ACTION_SEND).apply {
+                type = "application/pdf"
+                putExtra(Intent.EXTRA_STREAM, uri)
+                addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION)
+            }
+            startActivity(Intent.createChooser(shareIntent, "Share PDF"))
+        } else {
+            Toast.makeText(context, "Failed to save PDF", Toast.LENGTH_SHORT).show()
+        }
+    }
+
     private fun initOpenCV() {
         if (!OpenCVLoader.initLocal()) {
             Log.e("OpenCV", "Initialization failed")

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

@@ -0,0 +1,29 @@
+package org.mydomain.myscan
+
+import android.graphics.Bitmap
+import android.graphics.pdf.PdfDocument
+import android.util.Log
+import java.io.File
+import java.io.FileOutputStream
+import java.io.IOException
+
+fun createPdfFromBitmaps(bitmaps: List<Bitmap>, outputFile: File): Boolean {
+    val document = PdfDocument()
+    try {
+        for ((index, bitmap) in bitmaps.withIndex()) {
+            val pageInfo = PdfDocument.PageInfo.Builder(bitmap.width, bitmap.height, index + 1).create()
+            val page = document.startPage(pageInfo)
+            page.canvas.drawBitmap(bitmap, 0f, 0f, null)
+            document.finishPage(page)
+        }
+        FileOutputStream(outputFile).use { outputStream ->
+            document.writeTo(outputStream)
+        }
+        return true
+    } catch (e: IOException) {
+        Log.e("MyScan", "Error writing PDF: ${e.message}")
+        return false
+    } finally {
+        document.close()
+    }
+}

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

@@ -7,6 +7,7 @@ import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.padding
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.automirrored.filled.ArrowBack
+import androidx.compose.material3.Button
 import androidx.compose.material3.CircularProgressIndicator
 import androidx.compose.material3.Icon
 import androidx.compose.material3.IconButton
@@ -22,7 +23,8 @@ import androidx.compose.ui.unit.dp
 fun PagePreviewScreen(
     image: Bitmap?,
     isProcessing: Boolean,
-    onBackPressed: () -> Unit
+    onBackPressed: () -> Unit,
+    onSavePressed: (Bitmap) -> Unit,
 ) {
     Box(modifier = Modifier.fillMaxSize()) {
         when {
@@ -39,6 +41,14 @@ fun PagePreviewScreen(
                     modifier = Modifier.fillMaxSize(),
                     contentScale = ContentScale.Fit
                 )
+                Button (
+                    onClick = { onSavePressed(image) },
+                    modifier = Modifier
+                        .align(Alignment.BottomCenter)
+                        .padding(16.dp)
+                ) {
+                    Text("Save as PDF")
+                }
             }
             else -> {
                 Text(

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

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8"?>
+<paths xmlns:android="http://schemas.android.com/apk/res/android">
+    <cache-path
+        name="pdfs"
+        path="pdfs/" />
+</paths>