Add android example app (#32)

* Add example app using SecretBox and SealedBox

* remove unnecessary files

* Fix build

* Fix existing files

* minor changes

* Fix themes

* Remove unnecesssary permissions

* Add constants for Shared Preference keys

* Fix backstack

* Add missing EOF

* Add missing EOF

* Remove unnecessary code

* Handle backstack

---------

Co-authored-by: Muzzammil <[email protected]>

android-example/build.gradle

@@ -28,6 +28,17 @@ android {
 
 dependencies {
     implementation 'androidx.appcompat:appcompat:1.6.1'
-    implementation 'com.google.android.material:material:1.12.0'
     implementation 'androidx.activity:activity:1.9.0'
+
+    implementation project(path: ':cryptology')
+
+    // Jetpack Navigation Component
+    implementation "androidx.navigation:navigation-fragment-ktx:2.7.7"
+    implementation "androidx.navigation:navigation-ui-ktx:2.7.7"
+
+    // Material Components for Android
+    implementation "com.google.android.material:material:1.12.0"
+
+    // DrawerLayout
+    implementation "androidx.drawerlayout:drawerlayout:1.2.0"
 }

android-example/src/main/AndroidManifest.xml

@@ -1,16 +1,29 @@
 <?xml version="1.0" encoding="utf-8"?>
-<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools">
+
+    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
+
+    <uses-feature
+        android:name="android.hardware.camera"
+        android:required="false" />
+
+    <uses-permission android:name="android.permission.CAMERA" />
+    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
 
     <application
-        android:allowBackup="true"
+        android:name=".util.App"
+        android:allowBackup="false"
         android:icon="@mipmap/ic_launcher"
         android:label="@string/app_name"
         android:roundIcon="@mipmap/ic_launcher_round"
         android:supportsRtl="true"
-        android:theme="@style/Theme.Cryptology">
+        android:theme="@style/Theme.Cryptology"
+        tools:targetApi="31">
+
         <activity
             android:name=".MainActivity"
-            android:exported="true" >
+            android:exported="true">
 
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />

android-example/src/main/java/io/xconn/androidexample/MainActivity.java

@@ -1,14 +1,125 @@
 package io.xconn.androidexample;
 
+import static io.xconn.androidexample.util.Helpers.bytesToHex;
+import static io.xconn.androidexample.util.Helpers.convertTo32Bytes;
+
 import android.os.Bundle;
 
+
 import androidx.appcompat.app.AppCompatActivity;
+import androidx.fragment.app.Fragment;
+import androidx.fragment.app.FragmentManager;
+import androidx.fragment.app.FragmentTransaction;
+
+import com.google.android.material.bottomnavigation.BottomNavigationView;
+
+import java.util.Objects;
+
+import io.xconn.cryptology.KeyPair;
+import io.xconn.cryptology.SealedBox;
+import io.xconn.cryptology.SecretBox;
+import io.xconn.androidexample.fragment.CameraFragment;
+import io.xconn.androidexample.fragment.GalleryFragment;
+import io.xconn.androidexample.util.App;
+import io.xconn.androidexample.util.Helpers;
 
-public class MainActivity extends AppCompatActivity {
+public class MainActivity extends AppCompatActivity implements Helpers.PasswordDialogListener {
+
+    private FragmentManager fragmentManager;
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
+
+        fragmentManager = getSupportFragmentManager();
+        BottomNavigationView bottomNavigationView = findViewById(R.id.bottom_navigation);
+
+        Fragment cameraFragment = new CameraFragment();
+        fragmentManager.beginTransaction().replace(R.id.frameLayout, cameraFragment).commit();
+
+        bottomNavigationView.setOnItemSelectedListener(item -> {
+            Fragment fragment = null;
+            if (item.getItemId() == R.id.menu_camera) {
+                fragment = new CameraFragment();
+            } else if (item.getItemId() == R.id.menu_gallery) {
+                fragment = new GalleryFragment();
+            }
+
+            if (fragment != null) {
+                Fragment currentFragment = fragmentManager.findFragmentById(R.id.frameLayout);
+
+                // Do nothing if already on the selected fragment
+                if (currentFragment != null && currentFragment.getClass().equals(fragment.getClass())) {
+                    return true;
+                }
+
+                // Clear the backstack
+                fragmentManager.popBackStackImmediate(null, FragmentManager.POP_BACK_STACK_INCLUSIVE);
+
+                FragmentTransaction transaction = fragmentManager.beginTransaction()
+                        .replace(R.id.frameLayout, fragment);
+
+                // Add to backstack if it's GalleryFragment
+                if (fragment instanceof GalleryFragment) {
+                    transaction.addToBackStack(null);
+                }
+
+                transaction.commit();
+                return true;
+            }
+            return false;
+        });
+
+        fragmentManager.addOnBackStackChangedListener(() -> {
+            Fragment currentFragment = fragmentManager.findFragmentById(R.id.frameLayout);
+
+            if (currentFragment instanceof CameraFragment) {
+                bottomNavigationView.setSelectedItemId(R.id.menu_camera);
+            } else if (currentFragment instanceof GalleryFragment) {
+                bottomNavigationView.setSelectedItemId(R.id.menu_gallery);
+            }
+        });
+
+        if (!App.getBoolean(App.PREF_IS_DIALOG_SHOWN)) {
+            Helpers.showPasswordDialog(this, this, false);
+        }
+    }
+
+
+    @Override
+    public boolean onPasswordSubmit(String password) {
+        if (password.isEmpty()) {
+            return false;
+        }
+
+        // Generate key pair
+        KeyPair keyPair = SealedBox.generateKeyPair();
+
+        // Convert public key to hexadecimal string and save it
+        String publicKey = bytesToHex(keyPair.getPublicKey());
+        App.saveString(App.PREF_PUBLIC_KEY, publicKey);
+
+        // Generate nonce and save it
+        byte[] nonce = SecretBox.generateNonce();
+        App.saveString(App.PREF_NONCE, bytesToHex(nonce));
+
+        // Encrypt private key with entered password and save it
+        byte[] encryptedPrivateKey = SecretBox.box(nonce, keyPair.getPrivateKey(),
+                Objects.requireNonNull(convertTo32Bytes(password)));
+        App.saveString(App.PREF_PRIVATE_KEY, bytesToHex(encryptedPrivateKey));
+
+        App.saveBoolean(App.PREF_IS_DIALOG_SHOWN, true);
+        return true;
+    }
+
+    @Override
+    public void onPasswordCancel() {
+
+    }
+
+    @Override
+    public void onDismissed(boolean dismissedAfterSubmit) {
+
     }
 }

android-example/src/main/java/io/xconn/androidexample/fragment/CameraFragment.java

@@ -0,0 +1,171 @@
+package io.xconn.androidexample.fragment;
+
+import static android.app.Activity.RESULT_OK;
+import static io.xconn.androidexample.util.Helpers.bytesToHex;
+import static io.xconn.androidexample.util.Helpers.hexToBytes;
+
+import android.Manifest;
+import android.annotation.SuppressLint;
+import android.content.Intent;
+import android.graphics.Bitmap;
+import android.os.Bundle;
+import android.provider.MediaStore;
+import android.util.Log;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.Toast;
+
+import androidx.activity.result.ActivityResultLauncher;
+import androidx.activity.result.contract.ActivityResultContracts;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.fragment.app.Fragment;
+
+import java.io.ByteArrayOutputStream;
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.util.Objects;
+
+import io.xconn.androidexample.R;
+import io.xconn.androidexample.util.App;
+import io.xconn.cryptology.SealedBox;
+
+public class CameraFragment extends Fragment {
+
+    private ActivityResultLauncher<String> cameraPermissionLauncher;
+    private ActivityResultLauncher<Intent> cameraLauncher;
+    private ActivityResultLauncher<Intent> galleryLauncher;
+
+    @Nullable
+    @Override
+    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container,
+                             @Nullable Bundle savedInstanceState) {
+        return inflater.inflate(R.layout.fragment_camera, container, false);
+    }
+
+    @Override
+    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
+        super.onViewCreated(view, savedInstanceState);
+        view.findViewById(R.id.button_capture).setOnClickListener(v ->
+                cameraPermissionLauncher.launch(Manifest.permission.CAMERA));
+        view.findViewById(R.id.button_select_photo).setOnClickListener(v -> openGallery());
+
+        // Initialize ActivityResultLaunchers
+        cameraLauncher = registerForActivityResult(
+                new ActivityResultContracts.StartActivityForResult(),
+                result -> {
+                    if (result.getResultCode() == RESULT_OK) {
+                        handleCameraResult(result.getData());
+                    }
+                }
+        );
+
+        galleryLauncher = registerForActivityResult(
+                new ActivityResultContracts.StartActivityForResult(),
+                result -> {
+                    if (result.getResultCode() == RESULT_OK) {
+                        handleGalleryResult(result.getData());
+                    }
+                }
+        );
+
+        // Initialize camera permission launcher
+        cameraPermissionLauncher = registerForActivityResult(
+                new ActivityResultContracts.RequestPermission(),
+                isGranted -> {
+                    if (isGranted) {
+                        startCamera();
+                    } else {
+                        Toast.makeText(requireContext(), "Camera permission denied",
+                                Toast.LENGTH_SHORT).show();
+                    }
+                }
+        );
+    }
+
+    @SuppressLint("QueryPermissionsNeeded")
+    private void startCamera() {
+        Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
+        if (takePictureIntent.resolveActivity(requireActivity().getPackageManager()) != null) {
+            cameraLauncher.launch(takePictureIntent);
+        } else {
+            Toast.makeText(requireContext(), "No camera app found", Toast.LENGTH_SHORT).show();
+        }
+    }
+
+    private void openGallery() {
+        Intent intent = new Intent(Intent.ACTION_PICK, MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
+        galleryLauncher.launch(intent);
+    }
+
+    private void handleCameraResult(@Nullable Intent data) {
+        assert data != null;
+        Bitmap bitmap = (Bitmap) Objects.requireNonNull(data.getExtras()).get("data");
+        assert bitmap != null;
+        byte[] imageData = bitmapToByteArray(bitmap);
+
+        byte[] publicKey = hexToBytes(App.getString(App.PREF_PUBLIC_KEY));
+        Log.d("PublicKey", "Public Key: " + bytesToHex(publicKey));
+
+        byte[] encryptedImageData = SealedBox.seal(imageData, publicKey);
+        saveImageToFile(encryptedImageData);
+    }
+
+    private void handleGalleryResult(@Nullable Intent data) {
+        try {
+            if (data != null && data.getData() != null) {
+                Bitmap bitmap = MediaStore.Images.Media.getBitmap(
+                        requireActivity().getContentResolver(), data.getData());
+                byte[] imageData = bitmapToByteArray(bitmap);
+
+                byte[] publicKey = hexToBytes(App.getString(App.PREF_PUBLIC_KEY));
+
+                byte[] encryptedImageData = SealedBox.seal(imageData, publicKey);
+                saveImageToFile(encryptedImageData);
+            }
+        } catch (IOException e) {
+            Log.w("IOException", e.getMessage(), e);
+        }
+    }
+
+    private byte[] bitmapToByteArray(Bitmap bitmap) {
+        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        bitmap.compress(Bitmap.CompressFormat.PNG, 100, baos);
+        return baos.toByteArray();
+    }
+
+    private void saveImageToFile(byte[] data) {
+        File directory = new File(requireContext().getFilesDir(), "cryptology");
+        if (!directory.exists()) {
+            if (!directory.mkdirs()) {
+                Toast.makeText(requireContext(), "Failed to create directory",
+                        Toast.LENGTH_SHORT).show();
+                return;
+            }
+        }
+
+        String fileName = "image_" + System.currentTimeMillis() + ".dat";
+        File file = new File(directory, fileName);
+
+        FileOutputStream fos = null;
+        try {
+            fos = new FileOutputStream(file);
+            fos.write(data);
+            Toast.makeText(requireContext(), "Image saved: " + file.getAbsolutePath(),
+                    Toast.LENGTH_SHORT).show();
+            Log.d("ImagePath", "Image saved: " + file.getAbsolutePath());
+        } catch (IOException e) {
+            Log.w("IOException", e.getMessage(), e);
+        } finally {
+            if (fos != null) {
+                try {
+                    fos.close();
+                } catch (IOException e) {
+                    Log.w("IOException", e.getMessage(), e);
+                }
+            }
+        }
+    }
+}