implement basic error handling

cameraview/src/main/java/com/otaliastudios/cameraview/CameraController.java

@@ -98,8 +98,7 @@ abstract class CameraController implements CameraPreview.SurfaceCallback {
                     mCameraCallbacks.dispatchOnCameraOpened(mOptions);
 
                 } catch (Exception e) {
-                    LOG.e("Error while starting the camera engine.", e);
+                    mCameraCallbacks.onError("Error while starting the camera engine.", e);
-                    throw new RuntimeException(e);
                 }
             }
         });
@@ -122,8 +121,7 @@ abstract class CameraController implements CameraPreview.SurfaceCallback {
                     mCameraCallbacks.dispatchOnCameraClosed();
 
                 } catch (Exception e) {
-                    LOG.e("Error while stopping the camera engine.", e);
+                    mCameraCallbacks.onError("Error while stopping the camera engine.", e);
-                    throw new RuntimeException(e);
                 }
             }
         });
@@ -140,8 +138,8 @@ abstract class CameraController implements CameraPreview.SurfaceCallback {
             LOG.i("Stop immediately. Stopped. State is:", ss());
         } catch (Exception e) {
             // Do nothing.
-            LOG.i("Stop immediately. Exception while stopping.", e);
             mState = STATE_STOPPED;
+            mCameraCallbacks.onError("Stop immediately. Exception while stopping.", e);
         }
     }
 
@@ -170,9 +168,7 @@ abstract class CameraController implements CameraPreview.SurfaceCallback {
                     mCameraCallbacks.dispatchOnCameraOpened(mOptions);
 
                 } catch (Exception e) {
-                    LOG.e("Error while restarting the camera engine.", e);
+                    mCameraCallbacks.onError("Error while restarting the camera engine.", e);
-                    throw new RuntimeException(e);
-
                 }
             }
         });

cameraview/src/main/java/com/otaliastudios/cameraview/CameraException.java

@@ -0,0 +1,11 @@
+package com.otaliastudios.cameraview;
+
+/**
+ * An object of this class describes an error that occurred during the normal runtime of the camera.
+ */
+public class CameraException extends RuntimeException {
+
+    public CameraException(String message, Throwable cause) {
+        super(message, cause);
+    }
+}

cameraview/src/main/java/com/otaliastudios/cameraview/CameraListener.java

@@ -130,4 +130,17 @@ public abstract class CameraListener {
 
     }
 
+    /**
+     * Notifies that an error occurred in any of the previously called methods.
+     *
+     * The default implementation will just throw the original exception again to prevent missing
+     * error handling. Override this method without calling the super method in order to implement
+     * custom error handling.
+     *
+     * @param exception the caught exception
+     */
+    @UiThread
+    public void onError(CameraException exception) {
+        throw exception;
+    }
 }

cameraview/src/main/java/com/otaliastudios/cameraview/CameraView.java

@@ -1308,6 +1308,7 @@ public class CameraView extends FrameLayout {
         void dispatchOnFocusEnd(@Nullable Gesture trigger, boolean success, PointF where);
         void dispatchOnZoomChanged(final float newValue, final PointF[] fingers);
         void dispatchOnExposureCorrectionChanged(float newValue, float[] bounds, PointF[] fingers);
+        void onError(String message, Exception cause);
     }
 
     private class Callbacks implements CameraCallbacks {
@@ -1555,6 +1556,24 @@ public class CameraView extends FrameLayout {
                 }
             });
         }
+
+        /**
+         * Log and redirect the given error information to the CameraListeners.
+         *
+         * @param message a message describing which camera action failed
+         * @param cause the original exception that caused the error
+         */
+        @Override
+        public void onError(String message, Exception cause) {
+            // log
+            LOG.e(message, cause);
+
+            // redirect
+            CameraException cameraException = new CameraException(message, cause);
+            for (CameraListener listener : mListeners) {
+                listener.onError(cameraException);
+            }
+        }
     }
 
     //endregion