Null activity on dialog

[daniele-athome]

Use the context variable defined in the outer scope.

java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.res.Resources android.content.Context.getResources()' on a null object reference
       at android.support.v4.content.ContextCompat.getColor(ContextCompat.java:434)
       at com.afollestad.materialdialogs.util.DialogUtils.getColor(DialogUtils.java:125)
       at com.afollestad.materialdialogs.MaterialDialog$Builder.<init>(MaterialDialog.java:519)
       at org.kontalk.ui.ComposeMessageFragment$9.onClick(ComposeMessageFragment.java:914)
       at org.kontalk.ui.AbstractComposeFragment$19.onActionClicked(AbstractComposeFragment.java:1686)
       at com.nispok.snackbar.Snackbar$4.onClick(Snackbar.java:677)
       at android.view.View.performClick(View.java:4781)
       at android.view.View$PerformClick.run(View.java:19874)
       at android.os.Handler.handleCallback(Handler.java:739)
       at android.os.Handler.dispatchMessage(Handler.java:95)
       at android.os.Looper.loop(Looper.java:135)
       at android.app.ActivityThread.main(ActivityThread.java:5254)
       at java.lang.reflect.Method.invoke(Method.java)
       at java.lang.reflect.Method.invoke(Method.java:372)
       at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:904)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:699)