Add Android PDF export with share sheet delivery

android/app/src/main/java/android/print/PdfPrintAdapterDriver.java

@@ -0,0 +1,105 @@
+package android.print;
+
+import android.os.Bundle;
+import android.os.CancellationSignal;
+import android.os.ParcelFileDescriptor;
+
+/**
+ * Drives a PrintDocumentAdapter straight to a PDF file, without the system
+ * print dialog. Lives in the android.print package because the
+ * LayoutResultCallback / WriteResultCallback constructors are package-private:
+ * both classes are public SDK types on the greylist, and same-package
+ * compilation is the established way apps subclass them (the technique behind
+ * the common WebView-to-PDF converters). Runs on whichever thread the adapter
+ * expects — for WebView adapters that is the main thread.
+ *
+ * The caller owns the CancellationSignal: cancelling it aborts an in-flight
+ * layout or write, and the cancelled callbacks below still close the adapter
+ * lifecycle and report through the listener (the caller's completion guard
+ * drops duplicate deliveries). Synchronous adapter failures are reported the
+ * same way instead of escaping as uncaught exceptions.
+ */
+public final class PdfPrintAdapterDriver {
+
+    public interface Listener {
+        void onSuccess();
+        void onFailure(String message);
+    }
+
+    private PdfPrintAdapterDriver() {}
+
+    public static void print(
+        final PrintDocumentAdapter adapter,
+        PrintAttributes attributes,
+        final ParcelFileDescriptor destination,
+        final CancellationSignal cancellationSignal,
+        final Listener listener
+    ) {
+        try {
+            adapter.onStart();
+            adapter.onLayout(
+                null,
+                attributes,
+                cancellationSignal,
+                new PrintDocumentAdapter.LayoutResultCallback() {
+                    @Override
+                    public void onLayoutFinished(PrintDocumentInfo info, boolean changed) {
+                        try {
+                            adapter.onWrite(
+                                new PageRange[] { PageRange.ALL_PAGES },
+                                destination,
+                                cancellationSignal,
+                                new PrintDocumentAdapter.WriteResultCallback() {
+                                    @Override
+                                    public void onWriteFinished(PageRange[] pages) {
+                                        finish(adapter);
+                                        listener.onSuccess();
+                                    }
+
+                                    @Override
+                                    public void onWriteFailed(CharSequence error) {
+                                        finish(adapter);
+                                        listener.onFailure(error == null ? "PDF write failed" : error.toString());
+                                    }
+
+                                    @Override
+                                    public void onWriteCancelled() {
+                                        finish(adapter);
+                                        listener.onFailure("PDF write cancelled");
+                                    }
+                                }
+                            );
+                        } catch (RuntimeException ex) {
+                            finish(adapter);
+                            listener.onFailure("PDF write could not start: " + ex);
+                        }
+                    }
+
+                    @Override
+                    public void onLayoutFailed(CharSequence error) {
+                        finish(adapter);
+                        listener.onFailure(error == null ? "PDF layout failed" : error.toString());
+                    }
+
+                    @Override
+                    public void onLayoutCancelled() {
+                        finish(adapter);
+                        listener.onFailure("PDF layout cancelled");
+                    }
+                },
+                new Bundle()
+            );
+        } catch (RuntimeException ex) {
+            finish(adapter);
+            listener.onFailure("PDF print could not start: " + ex);
+        }
+    }
+
+    private static void finish(PrintDocumentAdapter adapter) {
+        try {
+            adapter.onFinish();
+        } catch (RuntimeException ignored) {
+            // The adapter may already be torn down with its WebView.
+        }
+    }
+}

android/app/src/main/java/io/github/renakoni/marktextandroid/AndroidDocumentsPlugin.java

@@ -326,6 +326,97 @@ public void shareMarkdownDocuments(PluginCall call) {
         }
     }
 
+    @PluginMethod
+    public void exportMarkdownPdf(PluginCall call) {
+        Activity activity = getActivity();
+        if (activity == null) {
+            call.reject("No Android activity is available for sharing", "SHARE_TARGET_UNAVAILABLE");
+            return;
+        }
+
+        String html = call.getString("html", null);
+        if (html == null || html.trim().length() == 0) {
+            call.reject("Rendered document content is required", "PDF_EXPORT_FAILED");
+            return;
+        }
+
+        String suggestedName = SharePreparation.normalizeSuggestedPdfName(call.getString("suggestedName", ""));
+        File outputFile;
+        try {
+            File exportDirectory = SharePreparation.getPdfExportCacheDirectory(getContext());
+            outputFile = new File(exportDirectory, suggestedName);
+            if (!SharePreparation.isFileInDirectory(outputFile, exportDirectory)) {
+                throw new SecurityException("PDF export path escaped the expected directory");
+            }
+        } catch (IOException | SecurityException ex) {
+            Log.e(TAG, "Failed to prepare PDF export directory", ex);
+            call.reject("Could not prepare the PDF file for sharing", "PDF_WRITE_FAILED", ex);
+            return;
+        }
+
+        final File pdfFile = outputFile;
+        final String displayName = suggestedName;
+        activity.runOnUiThread(() ->
+            PdfExporter.export(activity, html, displayName, pdfFile, new PdfExporter.Callback() {
+                @Override
+                public void onSuccess() {
+                    sharePdfExport(call, activity, pdfFile, displayName);
+                }
+
+                @Override
+                public void onFailure(String code, String message) {
+                    call.reject(message, code);
+                }
+            })
+        );
+    }
+
+    private void sharePdfExport(PluginCall call, Activity activity, File pdfFile, String displayName) {
+        try {
+            Uri pdfUri = FileProvider.getUriForFile(
+                getContext(),
+                getContext().getPackageName() + ".fileprovider",
+                pdfFile
+            );
+            Intent shareIntent = new Intent(Intent.ACTION_SEND);
+            shareIntent.setType("application/pdf");
+            shareIntent.putExtra(Intent.EXTRA_STREAM, pdfUri);
+            shareIntent.putExtra(Intent.EXTRA_TITLE, displayName);
+            shareIntent.putExtra(Intent.EXTRA_SUBJECT, displayName);
+            shareIntent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
+            ArrayList<Uri> streamUris = new ArrayList<>();
+            streamUris.add(pdfUri);
+            shareIntent.setClipData(SharePreparation.buildShareClipData(getContext(), displayName, streamUris));
+
+            Intent chooser = Intent.createChooser(shareIntent, "Share PDF");
+            chooser.putExtra(
+                Intent.EXTRA_EXCLUDE_COMPONENTS,
+                new ComponentName[] { new ComponentName(getContext(), MainActivity.class) }
+            );
+            chooser.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
+            activity.startActivity(chooser);
+
+            JSObject result = new JSObject();
+            result.put("displayName", displayName);
+            result.put("mimeType", "application/pdf");
+            result.put("bytes", pdfFile.length());
+            Log.i(
+                TAG,
+                "Opened Android share sheet for exported PDF: " +
+                safeForLog(displayName) +
+                ", bytes=" +
+                pdfFile.length()
+            );
+            call.resolve(result);
+        } catch (ActivityNotFoundException ex) {
+            Log.w(TAG, "No Android share target is available", ex);
+            call.reject("No Android share target is available", "SHARE_TARGET_UNAVAILABLE", ex);
+        } catch (RuntimeException ex) {
+            Log.e(TAG, "Failed to share exported PDF", ex);
+            call.reject("Could not prepare the PDF file for sharing", "PDF_WRITE_FAILED", ex);
+        }
+    }
+
     @PluginMethod
     public void renameMarkdownDocument(PluginCall call) {
         String sourceUri = call.getString("sourceUri", "");