Crash in Dragger.java line 246

[RoboErikG]

We're somehow finding a connection candidate without a view associated with its block. This shouldn't be possible but it seems our view and model hierarchy can get out of sync.

02-29 17:14:54.574 5518-5518/com.google.blockly.demo D/AndroidRuntime: Shutting down VM
02-29 17:14:54.584 5518-5518/com.google.blockly.demo E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.google.blockly.demo, PID: 5518
java.lang.NullPointerException: Attempt to invoke virtual method 'void com.google.blockly.ui.BlockView.setHighlightedConnection(com.google.blockly.model.Connection)' on a null object reference
at com.google.blockly.control.Dragger.continueDragging(Dragger.java:246)
at com.google.blockly.control.Dragger$1.onDrag(Dragger.java:102)
at android.view.View.dispatchDragEvent(View.java:18321)
at android.view.ViewGroup.dispatchDragEvent(ViewGroup.java:1492)
at android.view.ViewGroup.dispatchDragEvent(ViewGroup.java:1441)
at android.view.ViewGroup.dispatchDragEvent(ViewGroup.java:1441)
at android.view.ViewGroup.dispatchDragEvent(ViewGroup.java:1441)
at android.view.ViewGroup.dispatchDragEvent(ViewGroup.java:1441)
at android.view.ViewGroup.dispatchDragEvent(ViewGroup.java:1441)
at android.view.ViewGroup.dispatchDragEvent(ViewGroup.java:1441)
at android.view.ViewGroup.dispatchDragEvent(ViewGroup.java:1441)
at android.view.ViewGroup.dispatchDragEvent(ViewGroup.java:1441)
at android.view.ViewGroup.dispatchDragEvent(ViewGroup.java:1441)
at android.view.ViewGroup.dispatchDragEvent(ViewGroup.java:1441)
at android.view.ViewGroup.dispatchDragEvent(ViewGroup.java:1441)
at android.view.ViewGroup.dispatchDragEvent(ViewGroup.java:1441)
at android.view.ViewRootImpl.handleDragEvent(ViewRootImpl.java:5073)
at android.view.ViewRootImpl.access$700(ViewRootImpl.java:99)
at android.view.ViewRootImpl$ViewRootHandler.handleMessage(ViewRootImpl.java:3271)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)

[RoboErikG]

I'm relatively certain this is a bug in the code that restores the workspace. We seem to be getting into a state where we have an extra copy of the blocks that were in the workspace previously, but they're not being added to the view.

[AnmAtAnm]

Fixed in #95