Null pointer exception when invoke interface method int org.solovyev.android.checkout.BillingRequests.purchase

[jshernandez15]

java.lang.NullPointerException: Attempt to invoke interface method 'int org.solovyev.android.checkout.BillingRequests.purchase(java.lang.String, java.lang.String, java.lang.String, org.solovyev.android.checkout.PurchaseFlow)' on a null object reference at com.habitrpg.android.habitica.ui.fragments.GemsPurchaseFragment.purchaseGems(GemsPurchaseFragment.java:123) at com.habitrpg.android.habitica.ui.fragments.GemsPurchaseFragment.lambda$onViewCreated$0(GemsPurchaseFragment.java:64) at com.habitrpg.android.habitica.ui.fragments.GemsPurchaseFragment$$Lambda$1.onClick(Unknown Source) at android.view.View.performClick(View.java:5716) at android.widget.TextView.performClick(TextView.java:10926) at android.view.View.onKeyUp(View.java:10758) at android.widget.TextView.onKeyUp(TextView.java:7311) at android.view.KeyEvent.dispatch(KeyEvent.java:3290) at android.view.View.dispatchKeyEvent(View.java:9852) at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1744) at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1744) at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1744) at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1744) at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1744) at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1744) at android.support.v4.widget.NestedScrollView.dispatchKeyEvent(NestedScrollView.java:514) at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1744) at android.support.v4.view.ViewPager.dispatchKeyEvent(ViewPager.java:2761) at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1744) at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1744) at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1744) at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1744) at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1744) at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1744) at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1744) at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1744) at com.android.internal.policy.PhoneWindow$DecorView.superDispatchKeyEvent(PhoneWindow.java:2861) at com.android.internal.policy.PhoneWindow.superDispatchKeyEvent(PhoneWindow.java:1851) at android.app.Activity.dispatchKeyEvent(Activity.java:2992) at android.support.v7.app.AppCompatActivity.dispatchKeyEvent(AppCompatActivity.java:541) at android.support.v7.view.WindowCallbackWrapper.dispatchKeyEvent(WindowCallbackWrapper.java:59) at android.support.v7.app.AppCompatDelegateImplBase$AppCompatWindowCallbackBase.dispatchKeyEvent(AppCompatDelegateImplBase.java:319) at android.support.v7.view.WindowCallbackWrapper.dispatchKeyEvent(WindowCallbackWrapper.java:59) at com.android.internal.policy.PhoneWindow$DecorView.dispatchKeyEvent(PhoneWindow.java:2735) at android.view.ViewRootImpl$ViewPostImeInputStage.processKeyEvent(ViewRootImpl.java:5332) at android.view.ViewRootImpl$ViewPostImeInputStage.onProcess(ViewRootImpl.java:5285) at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4731) at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4784) at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4750) at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:4891) at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4758) at android.view.ViewRootImpl$AsyncInputStage.apply(ViewRootImpl.java:4948) at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4731) at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4784) at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4750) at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4758) at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4731) at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4784) at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4750) at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:4924) at android.view.ViewRootImpl$ImeInputStage.onFinishedInputEvent(ViewRootImpl.java:5169) at android.view.inputmethod.InputMethodManager$PendingEvent.run(InputMethodManager.java:2907) at android.view.inputmethod.InputMethodManager.invokeFinishedInputEventCallback(InputMethodManager.java:2479) at android.view.inputmethod.InputMethodManager.finishedInputEvent(InputMethodManager.java:2470) at android.view.inputmethod.InputMethodManager$ImeInputEventSender.onInputEventFinished(InputMethodManager.java:2884) at android.view.InputEventSender.dispatchInputEventFinished(InputEventSender.java:141) at android.os.MessageQueue.nativePollOnce(Native Method) at android.os.MessageQueue.next(MessageQueue.java:323) at android.os.Looper.loop(Looper.java:135) at android.app.ActivityThread.main(ActivityThread.java:7325) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)