Support switching to the front-facing camera in ScannerActivity

Close #8

app/src/main/java/me/impy/aegis/ui/ScannerActivity.java

@@ -2,7 +2,10 @@ package me.impy.aegis.ui;
 
 import android.content.Context;
 import android.content.Intent;
+import android.hardware.Camera;
 import android.os.Bundle;
+import android.view.Menu;
+import android.view.MenuItem;
 import android.widget.Toast;
 
 import com.google.zxing.BarcodeFormat;
@@ -12,14 +15,20 @@ import java.util.Collections;
 
 import me.dm7.barcodescanner.core.IViewFinder;
 import me.dm7.barcodescanner.zxing.ZXingScannerView;
+import me.impy.aegis.R;
 import me.impy.aegis.crypto.KeyInfo;
 import me.impy.aegis.crypto.KeyInfoException;
 import me.impy.aegis.db.DatabaseEntry;
 import me.impy.aegis.helpers.SquareFinderView;
 import me.impy.aegis.ui.views.KeyProfile;
 
+import static android.hardware.Camera.CameraInfo.CAMERA_FACING_BACK;
+import static android.hardware.Camera.CameraInfo.CAMERA_FACING_FRONT;
+
 public class ScannerActivity extends AegisActivity implements ZXingScannerView.ResultHandler {
     private ZXingScannerView _scannerView;
+    private Menu _menu;
+    private int _facing = CAMERA_FACING_BACK;
 
     @Override
     protected void onCreate(Bundle state) {
@@ -33,11 +42,51 @@ public class ScannerActivity extends AegisActivity implements ZXingScannerView.R
         };
         _scannerView.setResultHandler(this);
         _scannerView.setFormats(Collections.singletonList(BarcodeFormat.QR_CODE));
-        _scannerView.startCamera();
+
+        int camera = getRearCameraId();
+        if (camera == -1) {
+            camera = getFrontCameraId();
+            if (camera == -1) {
+                Toast.makeText(this, "No cameras available", Toast.LENGTH_LONG).show();
+                finish();
+            }
+            _facing = CAMERA_FACING_FRONT;
+        }
+        _scannerView.startCamera(camera);
 
         setContentView(_scannerView);
     }
 
+    @Override
+    public boolean onCreateOptionsMenu(Menu menu) {
+        _menu = menu;
+        getMenuInflater().inflate(R.menu.menu_scanner, menu);
+        updateCameraIcon();
+        return true;
+    }
+
+    @Override
+    public boolean onOptionsItemSelected(MenuItem item) {
+        switch (item.getItemId()) {
+            case R.id.action_camera:
+                _scannerView.stopCamera();
+                switch (_facing) {
+                    case CAMERA_FACING_BACK:
+                        _facing = CAMERA_FACING_FRONT;
+                        break;
+                    case CAMERA_FACING_FRONT:
+                        _facing = CAMERA_FACING_BACK;
+                        break;
+                }
+                _scannerView.startCamera(getCameraId(_facing));
+                updateCameraIcon();
+                return true;
+            case R.id.action_lock:
+            default:
+                return super.onOptionsItemSelected(item);
+        }
+    }
+
     @Override
     protected void setPreferredTheme(boolean nightMode) {
 
@@ -46,6 +95,7 @@ public class ScannerActivity extends AegisActivity implements ZXingScannerView.R
     @Override
     public void onResume() {
         super.onResume();
+        _scannerView.startCamera();
     }
 
     @Override
@@ -72,4 +122,42 @@ public class ScannerActivity extends AegisActivity implements ZXingScannerView.R
 
         _scannerView.resumeCameraPreview(this);
     }
+
+    private void updateCameraIcon() {
+        if (_menu != null) {
+            MenuItem item = _menu.findItem(R.id.action_camera);
+            boolean dual = getFrontCameraId() != -1 && getRearCameraId() != -1;
+            if (dual) {
+                switch (_facing) {
+                    case CAMERA_FACING_BACK:
+                        item.setIcon(R.drawable.ic_camera_front_24dp);
+                        break;
+                    case CAMERA_FACING_FRONT:
+                        item.setIcon(R.drawable.ic_camera_rear_24dp);
+                        break;
+                }
+            }
+            item.setVisible(dual);
+        }
+    }
+
+    private static int getCameraId(int facing) {
+        Camera.CameraInfo info = new Camera.CameraInfo();
+        for (int i = 0; i < Camera.getNumberOfCameras(); ++i) {
+            Camera.getCameraInfo(i, info);
+            if (info.facing == facing) {
+                return i;
+            }
+        }
+
+        return -1;
+    }
+
+    private static int getRearCameraId() {
+        return getCameraId(CAMERA_FACING_BACK);
+    }
+
+    private static int getFrontCameraId() {
+        return getCameraId(CAMERA_FACING_FRONT);
+    }
 }

app/src/main/res/drawable/ic_camera_front_24dp.xml

@@ -0,0 +1,7 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:height="24dp"
+    android:width="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24">
+    <path android:fillColor="#fff" android:pathData="M7,2H17V12.5C17,10.83 13.67,10 12,10C10.33,10 7,10.83 7,12.5M17,0H7A2,2 0 0,0 5,2V16A2,2 0 0,0 7,18H17A2,2 0 0,0 19,16V2A2,2 0 0,0 17,0M12,8A2,2 0 0,0 14,6A2,2 0 0,0 12,4A2,2 0 0,0 10,6A2,2 0 0,0 12,8M14,20V22H19V20M10,20H5V22H10V24L13,21L10,18V20Z" />
+</vector>

app/src/main/res/drawable/ic_camera_rear_24dp.xml

@@ -0,0 +1,7 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:height="24dp"
+    android:width="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24">
+    <path android:fillColor="#fff" android:pathData="M12,6C10.89,6 10,5.1 10,4A2,2 0 0,1 12,2C13.09,2 14,2.9 14,4A2,2 0 0,1 12,6M17,0H7A2,2 0 0,0 5,2V16A2,2 0 0,0 7,18H17A2,2 0 0,0 19,16V2A2,2 0 0,0 17,0M14,20V22H19V20M10,20H5V22H10V24L13,21L10,18V20Z" />
+</vector>

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

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="utf-8"?>
+<menu
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    tools:context="me.impy.aegis.ui.ScannerActivity">
+    <item
+        android:id="@+id/action_camera"
+        android:icon="@drawable/ic_camera_front_24dp"
+        android:title="Switch camera"
+        app:showAsAction="always"/>
+
+</menu>