android.content.ActivityNotFoundException:

Maybe you need to check that you added the new activity to the manifest.xml file

Example:

<activity
      android:name=".className" 
      android:label="@string/app_name" > 
</activity>

If other people are encountering something similar and arrive at this post, an issue I had may save you some time. May not be related to the OP's problem but def related to the ActivityNotFound exception.

I was trying to load an activity by using:

Intent intent = new Intent( this, class );

However I continuously kept getting the ActivityNotFoundException even though I had checked and rechecked the code multiple times.

This exception I was getting wasn't actually being caused by the intent but some code I was running inside the loaded activity throwing a RuntimeException. (my issue was caused by Typeface.createFromAsset())

It is possible you are running into a similar RuntimeException in your activity.

To see if this is the case, put your intent code in try catch blocks. Like so:

try {
    /* your code */
    ...
} catch ( ActivityNotFoundException e) {
    e.printStackTrace();
}

Run your app again, and check your LogCat, if it's the same issue, you'll get a RuntimeException with a "Caused By:" entry pointing to your actual issue.

I spent a good hour trying to figure this out. Hopefully this may save someone some time.

The activity you are calling should appear not only in the Manifest for its own package, but in the Manifest for the CALLING package, too.

Delete your activity from the manifest and then add it again. This type do not write type the XML directly. Instead, go to Application > Application nodes > add, choose the Activity, and then browse for the file source.

This worked for me.

intent.setClass takes parameters as "Package Context" and "Class". an example would be:

intent.setClass(CurrentActivity.this, TargetActivity.class);

also you need to check if the activity is registered in manifest file.