Crash : IllegalStateException

[AndroidDeveloperLB]

Got this exception while pressing the middle button twice in a row:

12-23 20:53:17.510 4883-4883/? E/AndroidRuntime: FATAL EXCEPTION: main
Process: uk.co.nickbutcher.adaptiveiconplayground, PID: 4883
java.lang.IllegalStateException: The specified child already has a parent. You must call removeView() on the child's parent first.
at android.view.ViewGroup.addViewInner(ViewGroup.java:4937)
at android.view.ViewGroup.addView(ViewGroup.java:4768)
at android.view.ViewGroup.addView(ViewGroup.java:4708)
at android.support.v7.widget.RecyclerView$5.addView(RecyclerView.java:751)
at android.support.v7.widget.ChildHelper.addView(ChildHelper.java:107)
at android.support.v7.widget.RecyclerView$LayoutManager.addViewInt(RecyclerView.java:7995)
at android.support.v7.widget.RecyclerView$LayoutManager.addView(RecyclerView.java:7953)
at android.support.v7.widget.RecyclerView$LayoutManager.addView(RecyclerView.java:7941)
at android.support.v7.widget.GridLayoutManager.layoutChunk(GridLayoutManager.java:579)
at android.support.v7.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1498)
at android.support.v7.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:591)
at android.support.v7.widget.GridLayoutManager.onLayoutChildren(GridLayoutManager.java:170)
at android.support.v7.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:3691)
at android.support.v7.widget.RecyclerView.dispatchLayout(RecyclerView.java:3408)
at android.support.v7.widget.RecyclerView.onLayout(RecyclerView.java:3960)
at android.view.View.layout(View.java:19659)
at android.view.ViewGroup.layout(ViewGroup.java:6075)
at android.support.design.widget.CoordinatorLayout.layoutChild(CoordinatorLayout.java:1166)
at android.support.design.widget.CoordinatorLayout.onLayoutChild(CoordinatorLayout.java:851)
at android.support.design.widget.CoordinatorLayout.onLayout(CoordinatorLayout.java:870)
at android.view.View.layout(View.java:19659)
at android.view.ViewGroup.layout(ViewGroup.java:6075)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
at android.view.View.layout(View.java:19659)
at android.view.ViewGroup.layout(ViewGroup.java:6075)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1791)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1635)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1544)
at android.view.View.layout(View.java:19659)
at android.view.ViewGroup.layout(ViewGroup.java:6075)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
at android.view.View.layout(View.java:19659)
at android.view.ViewGroup.layout(ViewGroup.java:6075)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1791)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1635)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1544)
at android.view.View.layout(View.java:19659)
at android.view.ViewGroup.layout(ViewGroup.java:6075)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
at com.android.internal.policy.DecorView.onLayout(DecorView.java:761)
at android.view.View.layout(View.java:19659)
at android.view.ViewGroup.layout(ViewGroup.java:6075)
at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:2496)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2212)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1392)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6752)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:911)
at android.view.Choreographer.doCallbacks(Choreographer.java:723)
at android.view.Choreographer.doFrame(Choreographer.java:658)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:897)
at android.os.Handler.handleCallback(Handler.java:790)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:164)
12-23 20:53:17.510 4883-4883/? E/AndroidRuntime: at android.app.ActivityThread.main(ActivityThread.java:6494)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)