add support for PDF outlines

app/build.gradle.kts

@@ -86,6 +86,7 @@ android {
 dependencies {
     implementation("androidx.appcompat:appcompat:1.7.0")
     implementation("androidx.core:core-ktx:1.15.0")
+    implementation("androidx.fragment:fragment-ktx:1.8.5")
     implementation("com.google.android.material:material:1.12.0")
 }
 

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

@@ -2,6 +2,10 @@ package app.grapheneos.pdfviewer
 
 import android.content.Context
 import android.net.Uri
+import android.view.View
+import android.view.ViewGroup.MarginLayoutParams
+import androidx.core.view.ViewCompat
+import androidx.core.view.WindowInsetsCompat
 import java.io.FileNotFoundException
 import java.io.IOException
 import java.io.InputStream
@@ -14,7 +18,6 @@ import java.io.OutputStream
     OutOfMemoryError::class
 )
 fun saveAs(context: Context, existingUri: Uri, saveAs: Uri) {
-
     context.asInputStream(existingUri)?.use { inputStream ->
         context.asOutputStream(saveAs)?.use { outputStream ->
             outputStream.write(inputStream.readBytes())
@@ -23,6 +26,20 @@ fun saveAs(context: Context, existingUri: Uri, saveAs: Uri) {
 
 }
 
+fun applySystemBarMargins(view: View, applyBottom: Boolean = false) {
+    ViewCompat.setOnApplyWindowInsetsListener(view) { v: View, windowInsets: WindowInsetsCompat ->
+        val insets = windowInsets.getInsets(WindowInsetsCompat.Type.systemBars())
+        val mlp = v.layoutParams as MarginLayoutParams
+        mlp.leftMargin = insets.left
+        mlp.rightMargin = insets.right
+        if (applyBottom) {
+            mlp.bottomMargin = insets.bottom
+        }
+        v.layoutParams = mlp
+        windowInsets
+    }
+}
+
 @Throws(FileNotFoundException::class)
 private fun Context.asInputStream(uri: Uri): InputStream? = contentResolver.openInputStream(uri)
 

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

@@ -14,7 +14,6 @@
 import android.view.MenuInflater;
 import android.view.MenuItem;
 import android.view.View;
-import android.view.ViewGroup;
 import android.webkit.CookieManager;
 import android.webkit.JavascriptInterface;
 import android.webkit.WebResourceRequest;
@@ -30,32 +29,31 @@
 import androidx.activity.result.contract.ActivityResultContracts;
 import androidx.annotation.NonNull;
 import androidx.appcompat.app.AppCompatActivity;
-import androidx.core.graphics.Insets;
-import androidx.core.view.ViewCompat;
-import androidx.core.view.WindowInsetsCompat;
 import androidx.fragment.app.Fragment;
+import androidx.fragment.app.FragmentTransaction;
 import androidx.lifecycle.ViewModelProvider;
 import androidx.loader.app.LoaderManager;
 import androidx.loader.content.Loader;
 
 import com.google.android.material.snackbar.Snackbar;
 
-import app.grapheneos.pdfviewer.databinding.PdfviewerBinding;
-import app.grapheneos.pdfviewer.fragment.DocumentPropertiesFragment;
-import app.grapheneos.pdfviewer.fragment.PasswordPromptFragment;
-import app.grapheneos.pdfviewer.fragment.JumpToPageFragment;
-import app.grapheneos.pdfviewer.ktx.ViewKt;
-import app.grapheneos.pdfviewer.loader.DocumentPropertiesAsyncTaskLoader;
-import app.grapheneos.pdfviewer.viewModel.PasswordStatus;
-
+import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.InputStream;
-import java.io.FileNotFoundException;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.HashMap;
 import java.util.List;
 
+import app.grapheneos.pdfviewer.databinding.PdfviewerBinding;
+import app.grapheneos.pdfviewer.fragment.DocumentPropertiesFragment;
+import app.grapheneos.pdfviewer.fragment.JumpToPageFragment;
+import app.grapheneos.pdfviewer.fragment.PasswordPromptFragment;
+import app.grapheneos.pdfviewer.ktx.ViewKt;
+import app.grapheneos.pdfviewer.loader.DocumentPropertiesAsyncTaskLoader;
+import app.grapheneos.pdfviewer.outline.OutlineFragment;
+import app.grapheneos.pdfviewer.viewModel.PdfViewModel;
+
 public class PdfViewer extends AppCompatActivity implements LoaderManager.LoaderCallbacks<List<CharSequence>> {
     public static final String TAG = "PdfViewer";
 
@@ -134,7 +132,7 @@ public class PdfViewer extends AppCompatActivity implements LoaderManager.Loader
     private Toast mToast;
     private Snackbar snackbar;
     private PasswordPromptFragment mPasswordPromptFragment;
-    public PasswordStatus passwordValidationViewModel;
+    public PdfViewModel viewModel;
 
     private final ActivityResultLauncher<Intent> openDocumentLauncher = registerForActivityResult(
             new ActivityResultContracts.StartActivityForResult(), result -> {
@@ -146,6 +144,7 @@ public class PdfViewer extends AppCompatActivity implements LoaderManager.Loader
                     mPage = 1;
                     mDocumentProperties = null;
                     mEncryptedDocumentPassword = "";
+                    viewModel.clearOutline();
                     loadPdf();
                     invalidateOptionsMenu();
                 }
@@ -165,6 +164,11 @@ public class PdfViewer extends AppCompatActivity implements LoaderManager.Loader
             });
 
     private class Channel {
+        @JavascriptInterface
+        public void setDocumentOutline(final String outline) {
+            viewModel.parseOutlineString(outline);
+        }
+
         @JavascriptInterface
         public int getPage() {
             return mPage;
@@ -232,17 +236,17 @@ public void showPasswordPrompt() {
             if (!getPasswordPromptFragment().isAdded()){
                 getPasswordPromptFragment().show(getSupportFragmentManager(), PasswordPromptFragment.class.getName());
             }
-            passwordValidationViewModel.passwordMissing();
+            viewModel.passwordMissing();
         }
 
         @JavascriptInterface
         public void invalidPassword() {
-            runOnUiThread(() -> passwordValidationViewModel.invalid());
+            runOnUiThread(() -> viewModel.invalid());
         }
 
         @JavascriptInterface
         public void onLoaded() {
-            passwordValidationViewModel.validated();
+            viewModel.validated();
             if (getPasswordPromptFragment().isAdded()) {
                 getPasswordPromptFragment().dismiss();
             }
@@ -261,20 +265,33 @@ protected void onCreate(Bundle savedInstanceState) {
         binding = PdfviewerBinding.inflate(getLayoutInflater());
         setContentView(binding.getRoot());
         setSupportActionBar(binding.toolbar);
-        passwordValidationViewModel = new ViewModelProvider(this, ViewModelProvider.AndroidViewModelFactory.getInstance(getApplication())).get(PasswordStatus.class);
+        viewModel = new ViewModelProvider(this, ViewModelProvider.AndroidViewModelFactory.getInstance(getApplication())).get(PdfViewModel.class);
+
+        viewModel.getOutline().observe(this, requested -> {
+            if (requested instanceof PdfViewModel.OutlineStatus.Requested) {
+                viewModel.setLoadingOutline();
+                binding.webview.evaluateJavascript("getDocumentOutline()", null);
+            }
+        });
+
+
+        getSupportFragmentManager().setFragmentResultListener(OutlineFragment.RESULT_KEY, this,
+                (requestKey, result) -> {
+            final int newPage = result.getInt(OutlineFragment.PAGE_KEY, -1);
+            if (viewModel.shouldAbortOutline()) {
+                Log.d(TAG, "aborting outline operations");
+                binding.webview.evaluateJavascript("abortDocumentOutline()", null);
+                viewModel.clearOutline();
+            } else {
+                onJumpToPageInDocument(newPage);
+            }
+        });
 
         EdgeToEdge.enable(this);
 
         // Margins for the toolbar are needed, so that content of the toolbar
         // is not covered by a system button navigation bar when in landscape.
-        ViewCompat.setOnApplyWindowInsetsListener(binding.toolbar, (v, windowInsets) -> {
-            Insets insets = windowInsets.getInsets(WindowInsetsCompat.Type.systemBars());
-            ViewGroup.MarginLayoutParams mlp = (ViewGroup.MarginLayoutParams) v.getLayoutParams();
-            mlp.leftMargin = insets.left;
-            mlp.rightMargin = insets.right;
-            v.setLayoutParams(mlp);
-            return windowInsets;
-        });
+        KtUtilsKt.applySystemBarMargins(binding.toolbar, false);
 
         binding.webview.setBackgroundColor(Color.TRANSPARENT);
 
@@ -446,6 +463,8 @@ public void onZoomEnd() {
         }
     }
 
+
+
     @Override
     protected void onDestroy() {
         super.onDestroy();
@@ -659,7 +678,8 @@ public boolean onPrepareOptionsMenu(@NonNull Menu menu) {
         final ArrayList<Integer> ids = new ArrayList<>(Arrays.asList(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_save_as));
+                R.id.action_view_document_properties, R.id.action_share, R.id.action_save_as,
+                R.id.action_outline));
         if (BuildConfig.DEBUG) {
             ids.add(R.id.debug_action_toggle_text_layer_visibility);
         }
@@ -713,6 +733,16 @@ public boolean onOptionsItemSelected(MenuItem item) {
         } else if (itemId == R.id.action_rotate_counterclockwise) {
             documentOrientationChanged(-90);
             return true;
+        } else if (itemId == R.id.action_outline) {
+            OutlineFragment outlineFragment =
+                    OutlineFragment.newInstance(mPage, getCurrentDocumentName());
+            getSupportFragmentManager().beginTransaction()
+                    .setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN)
+                    // fullscreen fragment, since content root view == activity's root view
+                    .add(android.R.id.content, outlineFragment)
+                    .addToBackStack(null)
+                    .commit();
+            return true;
         } else if (itemId == R.id.action_view_document_properties) {
             DocumentPropertiesFragment
                 .newInstance(mDocumentProperties)

app/src/main/java/app/grapheneos/pdfviewer/fragment/PasswordPromptFragment.kt

@@ -6,15 +6,14 @@ import android.os.Bundle
 import android.text.Editable
 import android.text.TextUtils
 import android.text.TextWatcher
-import android.view.LayoutInflater
 import android.view.WindowManager
 import android.view.inputmethod.EditorInfo.IME_ACTION_DONE
 import androidx.appcompat.app.AlertDialog
 import androidx.fragment.app.DialogFragment
 import app.grapheneos.pdfviewer.PdfViewer
 import app.grapheneos.pdfviewer.R
 import app.grapheneos.pdfviewer.databinding.PasswordDialogFragmentBinding
-import app.grapheneos.pdfviewer.viewModel.PasswordStatus
+import app.grapheneos.pdfviewer.viewModel.PdfViewModel
 import com.google.android.material.dialog.MaterialAlertDialogBuilder
 import com.google.android.material.textfield.TextInputEditText
 import com.google.android.material.textfield.TextInputLayout
@@ -50,20 +49,20 @@ class PasswordPromptFragment : DialogFragment() {
         isCancelable = false
         dialog.setCanceledOnTouchOutside(false)
         dialog.window?.setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_VISIBLE)
-        (requireActivity() as PdfViewer).passwordValidationViewModel.status.observe(
+        (requireActivity() as PdfViewer).viewModel.passwordStatus.observe(
             this
         ) {
             when (it) {
-                PasswordStatus.Status.MissingPassword -> {
+                PdfViewModel.PasswordStatus.MissingPassword -> {
                     passwordEditText.editableText.clear()
                     passwordDialogFragmentBinding.title.setText(R.string.password_prompt_description)
                 }
-                PasswordStatus.Status.InvalidPassword -> {
+                PdfViewModel.PasswordStatus.InvalidPassword -> {
                     passwordEditText.editableText.clear()
                     passwordDialogFragmentBinding.pdfPasswordTextInputLayout.error =
                         "invalid password"
                 }
-                PasswordStatus.Status.Validated -> {
+                PdfViewModel.PasswordStatus.Validated -> {
                     //Activity will dismiss the dialog
                 }
                 else -> {