How to take a scrolling screenshot of a Fragment in Android using View.MeasureSpec?

Question

I want to take a screenshot programmatically of a Fragment. The screenshot must include even the portion that is yet to be seen by the user, i.e. the unscrolled portion of the activity.

Method 1

I have referred to this question on StackOverflow and implemented this code:

public boolean takeScreenShot() {
    Bitmap bitmap = getScreenBitmap();
    return saveBitmap(bitmap); // function to save the screenshot as a JPEG on the device
}

public Bitmap getScreenBitmap() {
    if (mFragment == null) return null; //mFragment is the Fragment whose screenshot I need
    View v = mFragment.getView(); //getView returns the rootView of the Fragment
    v.setDrawingCacheEnabled(true);
    /*The line causing trouble: v.measure(MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED), MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED));*/
    v.layout(0, 0, v.getMeasuredWidth(), v.getMeasuredHeight());

    Bitmap bitmap = Bitmap.createBitmap(v.getMeasuredWidth(), v.getMeasuredHeight(), Bitmap.Config.ARGB_8888);
    Canvas c = new Canvas(bitmap);
    v.draw(c);
    v.setDrawingCacheEnabled(false);
    return bitmap;
}

If I execute the above code with the v.measure() line commented, I get a regular screenshot (excluding the yet-to-be-scrolled portion).

If I remove the comment and execute, the app crashes and I get this error:

java.lang.IllegalArgumentException: width and height must be > 0
    at android.graphics.Bitmap.createBitmap(Bitmap.java:810)
    at android.graphics.Bitmap.createBitmap(Bitmap.java:789)
    at android.graphics.Bitmap.createBitmap(Bitmap.java:756)
    at com.company.mypackage.custom.MyTestActivity.getScreenBitmap(MyTestActivity.java:180)

Method 2

If I replace the createBitmap line in the above code snippet with

Bitmap b = Bitmap.createBitmap(v.getDrawingCache());

I get a NullPointerException at this line because v.getDrawingCache() returns null.

Method 3

I have tried PGSSoft's scrollscreenshot tool and executed this command after downloading the necessary packages (I have checked that the device number for my emulator is 5, and that I am executing it in the correct directory)

java -cp scrollscreenshot-latest.jar com.pgssoft.scrollscreenshot.ScrollScreenShot -i 5

This gives me this error:

Error: Could not find or load main class com.pgssoft.scrollscreenshot.ScrollScreenShot

Could anyone guide me as to how to proceed?