Error inflating class android.support.v4.view.ViewPager

Question

I've been trying to create a Pager for my application that runs on <uses-sdk android:minSdkVersion="10" android:targetSdkVersion="15" /> I wrote my code according to this blog post.

XML for Pager activity:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <android.support.v4.view.ViewPager
        android:id="@+id/instructionsViewPager"
        android:layout_width="match_parent"
        android:layout_height="match_parent" /> 
</LinearLayout>

Code for adapter:

public class MyPagerAdapter extends PagerAdapter {

    @Override
    public int getCount() {
        // TODO Auto-generated method stub
        return 2;
    }

    @Override
    public boolean isViewFromObject(View arg0, Object arg1) {
        return (arg0 == ((View) arg1));
    }

    @Override
    public void destroyItem(ViewGroup container, int position, Object object) {
        ((ViewPager) container).removeView((View) object);
    }

    @Override
    public Object instantiateItem(ViewGroup container, int position) {
        LayoutInflater inflater = (LayoutInflater) container.getContext()
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        int resId = 0;
        switch (position) {
        case 1:
            resId = R.layout.instructions_page1;
            break;
        case 2:
            resId = R.layout.instructions_page2;
            break;
        }
        View view = inflater.inflate(resId, null);
        ((ViewPager) container).addView(view, 0);
        return view;
    }
}

Code for activity

public class Instructions extends Activity {

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.instructions);

        MyPagerAdapter adapter = new MyPagerAdapter();
        ViewPager pager = (ViewPager) findViewById(R.id.instructionsViewPager);
        pager.setAdapter(adapter);
        pager.setCurrentItem(0);
    }
}

for some reason, when I run this app, I get this following error list:

05-28 09:38:54.535: E/AndroidRuntime(18658): FATAL EXCEPTION: main
05-28 09:38:54.535: E/AndroidRuntime(18658): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.thepoosh/com.thepoosh.Instructions}: android.view.InflateException: Binary XML file line #7: Error inflating class android.support.v4.view.ViewPager
05-28 09:38:54.535: E/AndroidRuntime(18658):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1651)
05-28 09:38:54.535: E/AndroidRuntime(18658):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1667)
05-28 09:38:54.535: E/AndroidRuntime(18658):    at android.app.ActivityThread.access$1500(ActivityThread.java:117)
05-28 09:38:54.535: E/AndroidRuntime(18658):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:935)
05-28 09:38:54.535: E/AndroidRuntime(18658):    at android.os.Handler.dispatchMessage(Handler.java:99)
05-28 09:38:54.535: E/AndroidRuntime(18658):    at android.os.Looper.loop(Looper.java:123)
05-28 09:38:54.535: E/AndroidRuntime(18658):    at android.app.ActivityThread.main(ActivityThread.java:3691)
05-28 09:38:54.535: E/AndroidRuntime(18658):    at java.lang.reflect.Method.invokeNative(Native Method)
05-28 09:38:54.535: E/AndroidRuntime(18658):    at java.lang.reflect.Method.invoke(Method.java:507)
05-28 09:38:54.535: E/AndroidRuntime(18658):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:847)
05-28 09:38:54.535: E/AndroidRuntime(18658):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:605)
05-28 09:38:54.535: E/AndroidRuntime(18658):    at dalvik.system.NativeStart.main(Native Method)
05-28 09:38:54.535: E/AndroidRuntime(18658): Caused by: android.view.InflateException: Binary XML file line #7: Error inflating class android.support.v4.view.ViewPager
05-28 09:38:54.535: E/AndroidRuntime(18658):    at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:581)
05-28 09:38:54.535: E/AndroidRuntime(18658):    at android.view.LayoutInflater.rInflate(LayoutInflater.java:623)
05-28 09:38:54.535: E/AndroidRuntime(18658):    at android.view.LayoutInflater.inflate(LayoutInflater.java:408)
05-28 09:38:54.535: E/AndroidRuntime(18658):    at android.view.LayoutInflater.inflate(LayoutInflater.java:320)
05-28 09:38:54.535: E/AndroidRuntime(18658):    at android.view.LayoutInflater.inflate(LayoutInflater.java:276)
05-28 09:38:54.535: E/AndroidRuntime(18658):    at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:207)
05-28 09:38:54.535: E/AndroidRuntime(18658):    at android.app.Activity.setContentView(Activity.java:1663)
05-28 09:38:54.535: E/AndroidRuntime(18658):    at com.thepoosh.Instructions.onCreate(Instructions.java:11)
05-28 09:38:54.535: E/AndroidRuntime(18658):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
05-28 09:38:54.535: E/AndroidRuntime(18658):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1615)
05-28 09:38:54.535: E/AndroidRuntime(18658):    ... 11 more
05-28 09:38:54.535: E/AndroidRuntime(18658): Caused by: java.lang.ClassNotFoundException: android.support.v4.view.ViewPager in loader dalvik.system.PathClassLoader[/data/app/com.thepoosh-1.apk]
05-28 09:38:54.535: E/AndroidRuntime(18658):    at dalvik.system.PathClassLoader.findClass(PathClassLoader.java:240)
05-28 09:38:54.535: E/AndroidRuntime(18658):    at java.lang.ClassLoader.loadClass(ClassLoader.java:551)
05-28 09:38:54.535: E/AndroidRuntime(18658):    at java.lang.ClassLoader.loadClass(ClassLoader.java:511)
05-28 09:38:54.535: E/AndroidRuntime(18658):    at android.view.LayoutInflater.createView(LayoutInflater.java:471)
05-28 09:38:54.535: E/AndroidRuntime(18658):    at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:570)
05-28 09:38:54.535: E/AndroidRuntime(18658):    ... 20 more

so, I know it's failing because I'm using the android.support.v4.view.ViewPager, I tried playing with that and changing to plain ViewPager and importing android.support.v13 but it didn't help...

any thoughts on how to fix this?

Answer 1

Make sure that you place your libraries in a common folder such as libs in your project.

Right click on the jar, then select Build Path and click on Add to Build Path.

That will add your library to your project. If everything is correct, you can see it in a generated "folder" in the project called "Referenced Libraries"

Answer 2

Go to Project → Properties → Java Build Path than select Order and Export tab.

Set android-support-v4.jar library checked and up it into top of the list. And clean and rebuild..It works for most of the cases

Answer 3

I simply Replaced the code with this and it worked

    <androidx.viewpager.widget.ViewPager
        android:id="@+id/main_tabPager"
        android:layout_width="match_parent">

Answer 4

When We use new adt JARS SHOULD put in folder called "libs"

Then libs -->use as source folder
and your jar > add to build path.

http://android.foxykeep.com/dev/how-to-fix-the-classdefnotfounderror-with-adt-17