Fix camera initialization

zxing-android-embedded/src/com/journeyapps/barcodescanner/CameraPreview.java

@@ -91,6 +91,11 @@ public interface StateListener {
     private boolean previewActive = false;
 
     private RotationListener rotationListener;
+    private int openedOrientation = -1;
+
+    // Delay after rotation change is detected before we reorientate ourselves.
+    // This is to avoid double-reinitialization when the Activity is destroyed and recreated.
+    private static final int ROTATION_LISTENER_DELAY_MS = 250;
 
     private List<StateListener> stateListeners = new ArrayList<>();
 
@@ -195,12 +200,12 @@ public boolean handleMessage(Message message) {
         @Override
         public void onRotationChanged(int rotation) {
             // Make sure this is run on the main thread.
-            stateHandler.post(new Runnable() {
+            stateHandler.postDelayed(new Runnable() {
                 @Override
                 public void run() {
                     rotationChanged();
                 }
-            });
+            }, ROTATION_LISTENER_DELAY_MS);
         }
     };
 
@@ -263,8 +268,11 @@ protected void initializeAttributes(AttributeSet attrs) {
     }
 
     private void rotationChanged() {
-        pause();
-        resume();
+        // Confirm that it did actually change
+        if(isActive() && getDisplayRotation() != openedOrientation) {
+            pause();
+            resume();
+        }
     }
 
     private void setupSurfaceView() {
@@ -550,6 +558,7 @@ public void pause() {
         Util.validateMainThread();
         Log.d(TAG, "pause()");
 
+        openedOrientation = -1;
         if (cameraInstance != null) {
             cameraInstance.close();
             cameraInstance = null;
@@ -640,11 +649,15 @@ private void initCamera() {
 
         cameraInstance.setReadyHandler(stateHandler);
         cameraInstance.open();
+
+        // Keep track of the orientation we opened at, so that we don't reopen the camera if we
+        // don't need to.
+        openedOrientation = getDisplayRotation();
     }
 
 
     private void startCameraPreview(CameraSurface surface) {
-        if (!previewActive) {
+        if (!previewActive && cameraInstance != null) {
             Log.i(TAG, "Starting preview");
             cameraInstance.setSurface(surface);
             cameraInstance.startPreview();

zxing-android-embedded/src/com/journeyapps/barcodescanner/camera/CameraManager.java

@@ -138,6 +138,9 @@ public void open() {
      * Must be called from camera thread.
      */
     public void configure() {
+        if(camera == null) {
+            throw new RuntimeException("Camera not open");
+        }
         setParameters();
     }
 
@@ -355,7 +358,7 @@ private void setParameters() {
         } catch (Exception e) {
             // Failed, use safe mode
             try {
-                setDesiredParameters(false);
+                setDesiredParameters(true);
             } catch (Exception e2) {
                 // Well, darn. Give up
                 Log.w(TAG, "Camera rejected even safe-mode parameters! No configuration");

zxing-android-embedded/src/com/journeyapps/barcodescanner/camera/CameraThread.java

@@ -33,13 +33,35 @@ private CameraThread() {
     }
 
     /**
-     * Call from main thread.
+     * Call from main thread or camera thread.
      *
      * Enqueues a task on the camera thread.
      *
      * @param runnable the task to enqueue
      */
     protected void enqueue(Runnable runnable) {
+        synchronized (LOCK) {
+            checkRunning();
+            this.handler.post(runnable);
+        }
+    }
+
+    /**
+     * Call from main thread or camera thread.
+     *
+     * Enqueues a task on the camera thread.
+     *
+     * @param runnable the task to enqueue
+     * @param delayMillis the delay in milliseconds before executing the runnable
+     */
+    protected void enqueueDelayed(Runnable runnable, long delayMillis) {
+        synchronized (LOCK) {
+            checkRunning();
+            this.handler.postDelayed(runnable, delayMillis);
+        }
+    }
+
+    private void checkRunning() {
         synchronized (LOCK) {
             if (this.handler == null) {
                 if (openCount <= 0) {
@@ -49,7 +71,6 @@ protected void enqueue(Runnable runnable) {
                 this.thread.start();
                 this.handler = new Handler(thread.getLooper());
             }
-            this.handler.post(runnable);
         }
     }