Android conflict after change package name. build.graden - > applicationId || Provider

I created an app with Android Studio and I have a problem now. To publish the app I have to change the package names so I have changed it.(before: com.example..). The app it's working perfect but in the build.graden the applicationId still having com.example. So when I change it I get the error below.

21:48:47 Session 'app': error

pkg: /data/local/tmp/wk.gon250.gonzalo.dublinweather
Failure [INSTALL_FAILED_CONFLICTING_PROVIDER]

Also I think the problem is on the ´Manifest´ with the provider. Take a look below:

 <provider
     android:authorities="wk.gon250.gonzalo.dublinweather.app"
     android:name=".data.WeatherProvider"
     android:exported="false"
     android:syncable="true" />

Note:

it´s working perfectly with:

    defaultConfig {
      applicationId "com.example.gonzalo.dublinweather.app"
      minSdkVersion 10
      targetSdkVersion 21
      versionCode 2
      versionName "1.1"
    }

but I need applicationId "wk.gon250.gonzalo.dublinweather.app"

I think the problem is with the database(sql lite) and I really don't know how to fix it.

I hope someone can help me! Thanks.