Fix the crash if stopRecording after release

camerafragment/src/main/java/com/github/florent37/camerafragment/internal/manager/impl/Camera1Manager.java

@@ -185,6 +185,9 @@ public class Camera1Manager extends BaseCameraManager<Integer, SurfaceHolder.Cal
             backgroundHandler.post(new Runnable() {
                 @Override
                 public void run() {
+                    // Tzutalin++ 2017/05. If calling release function, it should not be executed
+                    if (context == null) return;
+
                     if (prepareVideoRecorder()) {
                         videoRecorder.start();
                         isVideoRecording = true;

camerafragment/src/main/java/com/github/florent37/camerafragment/internal/manager/impl/Camera2Manager.java

@@ -267,6 +267,9 @@ public final class Camera2Manager extends BaseCameraManager<String, TextureView.
             backgroundHandler.post(new Runnable() {
                 @Override
                 public void run() {
+                    // Tzutalin++ 2017/05. If calling release function, it should not be executed
+                    if (context == null) return;
+
                     closePreviewSession();
                     if (prepareVideoRecorder()) {