UPDATE: This has been fixed in MoPub 4.1.0.
MoPub 4.0 gets an InflateException if your
<application> element in AndroidManifest.xml does not have an
The problem is in
NativeAd, in MoPub 4.0 the constructor changed to
mContext = context.getApplicationContext();. So in
NativeAd.createAdView() it passes the Application Context to the ad renderer for View inflation. But application contexts in general are not required to have a theme. So it chokes when trying to resolve Android resource attributes.
My proposed fix is here: https://github.com/mopub/mopub-android-sdk/pull/184