In my code I
import android.support.v4.view.ViewPager
but I get a ClassNotFoundException: android.support.v4.view.ViewPager when I set content view to this xml file:
...
<android.support.v4.app.FragmentPager
android:layout_height="0px"
android:layout_width="match_parent"
android:layout_weight="1"
android:id="@+id/pager">
</android.support.v4.app.FragmentPager>
...
You have to add compatibility library by right clicking your project and selecting Android Tools -> Add Compatibility Library. Once its added, clean your project and build again.
i'm using Android Studio Beta 0.8.6 and i had to do it this way
File -> Project Structure
Go to <Your android apk folder>\sdk\extras\android\support\v4 folder and add android-support-v4.jar to app library (or whole sdk library).
Add Support library by right clicking your project and selecting Android Tools -> Add Compatibility Library. After adding Support Library clean your project and Go to Java Build Path, Go to Order and Export [Last tab] click all currently added Jar files and libraries..press Ok and refresh your Project.. It works fine for me..
You should add android.support.v4 jar to your app.
If it is not gradle based then You should Migrate Eclipse ADT based project to Gradle based.. Import Project into android studio..
I had this problem please right click on your project and click Android Tools and now click Support Libraries and then Accept License Now Run your Project It will Work :D
RightClick==>Android Tools==>Support Libraries ==>Accept License
来源:https://stackoverflow.com/questions/10199430/android-class-not-found-exception-android-support-v4-app-fragmentpager