Question

I do have lots of plain old activity-based apps in the Play Store. Since two days I try to do my first steps with Fragments. I still don’t get it. I’ve read mostly all docs and blogs and guides about Fragments but my stupid simple test app refuses to start with an ClassNotFoundException on MyActivity.

So here’s what I did so far:

The starting FragmentActivity called MyActivity:

public class MyActivity extends FragmentActivity {

    @Override
    public void onCreate(Bundle bundle) {
        super.onCreate(bundle);

        setContentView(R.layout.myactivity);
    }
}

Here’s the layout/myactivity.xml:

<LinearLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="horizontal" >

    <fragment
        class="com.test.app.Table1List"
        android:id="@+id/table1list"
        android:layout_height="match_parent"
        android:layout_width="match_parent" />
</LinearLayout>

This is the ListFragment with its XML file:

public class Table1List extends ListFragment {

    @Override
    public View onCreateView(LayoutInflater layoutInflater, ViewGroup viewGroup, Bundle bundle) {
        if (viewGroup == null) {
            return null;
        }

        return layoutInflater.inflate(R.layout.table1list, viewGroup);
    }
}

<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal" >

    <ListView
        android:drawSelectorOnTop="false"
        android:fastScrollEnabled="true" 
        android:id="@id/android:list"
        android:layout_height="fill_parent"
        android:layout_width="fill_parent" />

    <TextView
        style="@style/TextViewMedium"
        android:id="@id/android:empty"
        android:text="@string/txt_noresult" />
</LinearLayout>

Call me stupid but I always do get an ActivityNotFoundException during start of the FragmentActivity called MyActivity.

Any help is highly appreciated.

EDIT:

I took the latest v4 Compatibility Package from several days ago. I issued clean projects nearly every 10 minutes – no go.

Here’s the Manifest:

<manifest
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:versionCode="1"
    android:versionName="1.0"
    package="com.test.app" >

    <uses-sdk
        android:minSdkVersion="7"
        android:targetSdkVersion="11" />

    <application
        android:hardwareAccelerated="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/txt_appname" >

        <activity
            android:label="@string/txt_appname"
            android:name="MyActivity" >

            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>
</manifest>

EDIT 2: Here’s the LogCat:

Unable to resolve superclass of Lcom/test/app/MyActivity; (25)
Link of class 'Lcom/test/app/MyActivity;' failed
Shutting down VM
threadid=3: thread exiting with uncaught exception (group=0x4001b188)
    Uncaught handler: thread main exiting due to uncaught exception
    java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.test.app/com.test.app.MyActivity}: java.lang.ClassNotFoundException: com.test.app.MyActivity in loader dalvik.system.PathClassLoader@44bfda38
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2417)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2512)
    at android.app.ActivityThread.access$2200(ActivityThread.java:119)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1863)
    at android.os.Handler.dispatchMessage(Handler.java:99)
    at android.os.Looper.loop(Looper.java:123)
    at android.app.ActivityThread.main(ActivityThread.java:4363)
    at java.lang.reflect.Method.invokeNative(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:521)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
    at dalvik.system.NativeStart.main(Native Method)
    Caused by: java.lang.ClassNotFoundException: com.test.app.MyActivity in loader dalvik.system.PathClassLoader@44bfda38
    at dalvik.system.PathClassLoader.findClass(PathClassLoader.java:243)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:573)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:532)
    at android.app.Instrumentation.newActivity(Instrumentation.java:1021)
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2409)
    ... 11 more

EDIT 3: I did re-install the support package, created a new project with Compatability Package v4, stripped down everything to just the MyActivity and one fragment –> same error. I even tested with the previous Support v4 package (Release 6).

These are my first steps with Fragments after nearly three years with Android development (lots of apps in the market). Seems that this whole thing is broken.

This is the project tree in eclipse – any help still highly required.

Answer 1

I don’t know if this will fix your problem but looking at your screenshot, everything looks correct to me except the Referenced Libraries item. That shouldn’t be there any more because the latest ADT version 17 automatically detects all jars in the libs folder. You can get rid of the Referenced Libraries item by removing the explicit reference to the android support jar from your build path.

I had a very similar problem and was completely stumped for a while until I read this blog post which has a lot of information about this issue so it might be worth a read even if removing the Referenced Libraries doesn’t work.