added feature to save document

app/src/main/java/app/grapheneos/pdfviewer/KtUtils.kt

@@ -0,0 +1,25 @@
+package app.grapheneos.pdfviewer
+
+import android.content.Context
+import android.net.Uri
+import java.io.FileNotFoundException
+import java.io.IOException
+import java.io.InputStream
+import java.io.OutputStream
+
+@Throws(FileNotFoundException::class, IOException::class)
+fun saveAs(context: Context, existingUri: Uri, saveAs: Uri) {
+
+    context.asInputStream(existingUri)?.use { inputStream ->
+        context.asOutputStream(saveAs)?.use { outputStream ->
+            outputStream.write(inputStream.readBytes())
+        }
+    }
+
+}
+
+@Throws(FileNotFoundException::class)
+private fun Context.asInputStream(uri: Uri): InputStream? = contentResolver.openInputStream(uri)
+
+@Throws(FileNotFoundException::class)
+private fun Context.asOutputStream(uri: Uri): OutputStream? = contentResolver.openOutputStream(uri)

app/src/main/java/app/grapheneos/pdfviewer/PdfViewer.java

@@ -132,6 +132,19 @@ public class PdfViewer extends AppCompatActivity implements LoaderManager.Loader
                 }
             });
 
+    private final ActivityResultLauncher<Intent> saveAsLauncher = registerForActivityResult(
+            new ActivityResultContracts.StartActivityForResult(), result -> {
+                if (result == null) return;
+                if (result.getResultCode() != RESULT_OK) return;
+                Intent resultData = result.getData();
+                if (resultData != null) {
+                    Uri path = resultData.getData();
+                    if (path != null) {
+                        saveDocumentAs(path);
+                    }
+                }
+            });
+
     private class Channel {
         @JavascriptInterface
         public int getPage() {
@@ -517,7 +530,7 @@ public class PdfViewer extends AppCompatActivity implements LoaderManager.Loader
         final int[] ids = {R.id.action_zoom_in, R.id.action_zoom_out, R.id.action_jump_to_page,
                 R.id.action_next, R.id.action_previous, R.id.action_first, R.id.action_last,
                 R.id.action_rotate_clockwise, R.id.action_rotate_counterclockwise,
-                R.id.action_view_document_properties, R.id.action_share };
+                R.id.action_view_document_properties, R.id.action_share, R.id.action_save_as};
         if (mDocumentState < STATE_LOADED) {
             for (final int id : ids) {
                 final MenuItem item = menu.findItem(id);
@@ -541,6 +554,7 @@ public class PdfViewer extends AppCompatActivity implements LoaderManager.Loader
         enableDisableMenuItem(menu.findItem(R.id.action_share), mUri != null);
         enableDisableMenuItem(menu.findItem(R.id.action_next), mPage < mNumPages);
         enableDisableMenuItem(menu.findItem(R.id.action_previous), mPage > 1);
+        enableDisableMenuItem(menu.findItem(R.id.action_save_as), mUri != null);
 
         return true;
     }
@@ -587,8 +601,42 @@ public class PdfViewer extends AppCompatActivity implements LoaderManager.Loader
         } else if (itemId == R.id.action_share) {
             shareDocument();
             return true;
+        } else if (itemId == R.id.action_save_as) {
+            saveDocument();
         }
 
         return super.onOptionsItemSelected(item);
     }
+
+    private void saveDocument() {
+        Intent intent = new Intent(Intent.ACTION_CREATE_DOCUMENT);
+        intent.addCategory(Intent.CATEGORY_OPENABLE);
+        intent.setType("application/pdf");
+        intent.putExtra(Intent.EXTRA_TITLE, getCurrentDocumentName());
+        saveAsLauncher.launch(intent);
+    }
+
+    private String getCurrentDocumentName() {
+        if (mDocumentProperties == null || mDocumentProperties.isEmpty()) return "";
+        String fileName = "";
+        String title = "";
+        for (CharSequence property : mDocumentProperties) {
+            if (property.toString().startsWith("File name:")) {
+                fileName = property.toString().replace("File name:", "");
+            }
+            if (property.toString().startsWith("Title:-")) {
+                title = property.toString().replace("Title:-", "");
+            }
+        }
+        return fileName.length() > 2 ? fileName : title;
+    }
+
+    private void saveDocumentAs(Uri uri) {
+        try {
+            KtUtilsKt.saveAs(this, mUri, uri);
+        } catch (IOException e) {
+            e.printStackTrace();
+            snackbar.setText(R.string.error_while_saving).show();
+        }
+    }
 }

app/src/main/res/drawable/ic_save_24dp.xml

@@ -0,0 +1,10 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24"
+    android:tint="?attr/colorControlNormal">
+  <path
+      android:fillColor="@android:color/white"
+      android:pathData="M17,3L5,3c-1.11,0 -2,0.9 -2,2v14c0,1.1 0.89,2 2,2h14c1.1,0 2,-0.9 2,-2L21,7l-4,-4zM19,19L5,19L5,5h11.17L19,7.83L19,19zM12,12c-1.66,0 -3,1.34 -3,3s1.34,3 3,3 3,-1.34 3,-3 -1.34,-3 -3,-3zM6,6h9v4L6,10z"/>
+</vector>

app/src/main/res/menu/pdf_viewer.xml

@@ -73,6 +73,12 @@
         android:title="@string/action_rotate_counterclockwise"
         app:showAsAction="ifRoom" />
 
+    <item
+        android:id="@+id/action_save_as"
+        android:icon="@drawable/ic_save_24dp"
+        android:title="@string/action_save_as"
+        app:showAsAction="never" />
+
     <item
         android:id="@+id/action_view_document_properties"
         android:title="@string/action_view_document_properties"

app/src/main/res/values/strings.xml

@@ -20,8 +20,10 @@
     <string name="invalid_mime_type">Cannot open file with invalid MIME type</string>
     <string name="legacy_file_uri">Cannot open legacy file paths from insecure apps</string>
     <string name="io_error">Received I/O error trying to open content</string>
+    <string name="error_while_saving">Error encountered while saving</string>
 
     <string name="webview_out_of_date_title">WebView out-of-date</string>
     <string name="webview_out_of_date_message">Your current WebView version is %d. The WebView should be at least version %d for the PDF Viewer to work.</string>
     <string name="action_share">Share</string>
+    <string name="action_save_as">Save as</string>
 </resources>