Add button to show QR code

app/src/main/java/net/bierbaumer/otp_authenticator/MainActivity.java

@@ -7,6 +7,8 @@
 import android.content.DialogInterface;
 import android.content.Intent;
 import android.content.pm.PackageManager;
+import android.graphics.Bitmap;
+import android.graphics.Color;
 import android.os.Bundle;
 import android.os.Handler;
 import android.support.annotation.NonNull;
@@ -16,6 +18,7 @@
 import android.support.v4.content.ContextCompat;
 import android.support.v7.app.AppCompatActivity;
 import android.support.v7.widget.Toolbar;
+import android.util.Log;
 import android.view.ActionMode;
 import android.view.LayoutInflater;
 import android.view.Menu;
@@ -27,10 +30,15 @@
 import android.webkit.WebView;
 import android.widget.AdapterView;
 import android.widget.EditText;
+import android.widget.ImageView;
 import android.widget.ListView;
 import android.widget.ProgressBar;
 
+import com.google.zxing.BarcodeFormat;
+import com.google.zxing.MultiFormatWriter;
+import com.google.zxing.WriterException;
 import com.google.zxing.client.android.Intents;
+import com.google.zxing.common.BitMatrix;
 import com.google.zxing.integration.android.IntentIntegrator;
 
 import java.util.ArrayList;
@@ -312,6 +320,30 @@ public void onClick(DialogInterface dialog, int whichButton) {
 
             alert.show();
 
+            return true;
+        } else if (id == R.id.action_qrcode) {
+            AlertDialog.Builder alert = new AlertDialog.Builder(this);
+
+            try {
+                BitMatrix bitMatrix = new MultiFormatWriter().encode("otpauth://totp/" + adapter.getCurrentSelection().getLabel() + "?secret=" + adapter.getCurrentSelection().getSecret(), BarcodeFormat.QR_CODE, 400, 400, null);
+                int height = bitMatrix.getHeight();
+                int width = bitMatrix.getWidth();
+                Bitmap bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.RGB_565);
+                for (int x = 0; x < width; x++) {
+                    for (int y = 0; y < height; y++) {
+                        bitmap.setPixel(x, y, bitMatrix.get(x, y) ? Color.BLACK : Color.WHITE);
+                    }
+                }
+                ImageView image = new ImageView(getApplicationContext());
+                image.setImageBitmap(bitmap);
+
+                alert.setView(image);
+
+                alert.show();
+            } catch (WriterException e) {
+                Log.e(MainActivity.class.getSimpleName(), e.getMessage());
+            }
+
             return true;
         }
 

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

@@ -3,6 +3,12 @@
     xmlns:tools="http://schemas.android.com/tools"
     >
 
+    <item
+            android:id="@+id/action_qrcode"
+            android:orderInCategory="100"
+            android:icon="@android:drawable/ic_menu_view"
+            app:showAsAction="ifRoom"
+            android:title="@string/menu_qrcode" />
     <item
         android:id="@+id/action_edit"
         android:orderInCategory="100"

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

@@ -2,6 +2,7 @@
     <string name="app_name">OTP Authenticator</string>
     <string name="app_launcher">Authenticator</string>
     <string name="no_accounts">No account has been added yet</string>
+    <string name="menu_qrcode">Show QR code</string>
     <string name="menu_delete">Delete</string>
     <string name="menu_edit">Edit</string>
     <string name="menu_scan">Scan QR Code</string>