Java.Lang.RuntimeException3Espera.Android.ViewsSettingsFragment+<PurchasePremium>d__2aMoveNext ()filename unknown

[flagbug]

at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x00000] in <filename unknown>:0 
  at Android.Runtime.JNIEnv.CallStaticObjectMethod (IntPtr jclass, IntPtr jmethod, Android.Runtime.JValue[] parms) [0x00000] in <filename unknown>:0 
  at Android.Widget.Toast.MakeText (Android.Content.Context context, Int32 resId, ToastLength duration) [0x00000] in <filename unknown>:0 
  at Espera.Android.Views.SettingsFragment+<PurchasePremium>d__2a.MoveNext () [0x00000] in <filename unknown>:0 
  --- End of managed exception stack trace ---
java.lang.NullPointerException
    at android.widget.Toast.makeText(Toast.java:265)
    at mono.java.lang.RunnableImplementor.n_run(Native Method)
    at mono.java.lang.RunnableImplementor.run(RunnableImplementor.java:29)
    at android.os.Handler.handleCallback(Handler.java:725)
    at android.os.Handler.dispatchMessage(Handler.java:92)
    at android.os.Looper.loop(Looper.java:158)
    at android.app.ActivityThread.main(ActivityThread.java:5751)
    at java.lang.reflect.Method.invokeNative(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:511)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1083)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:850)
    at dalvik.system.NativeStart.main(Native Method)

Probable explanation:
The user clicks on the "Purchase Premium" button, but immediately backs out of the settings fragment. This causes this.Activity to be null when the toast is created.