SecurityException: Permission Denial requires null

I would like to launch the market from a preference screen but when I try to do this I obain a java.lang.SecurityException: Permission Denial: starting Intent { cmp=com.action.test/.ui开发者_如何学Python.activities.Test } from ProcessRecord{44db1300 3697:com.pippo.pluto/10067} (pid=3697, uid=10067) requires null. This is my code:

startActivity(new Intent(Intent.ACTION_VIEW,Uri.parse("market://search?q=pname:com.action.test")));

what am I doing wrong?

Thanks in advance Tobia

I did the following:

private class SupportDevListener implements OnPreferenceClickListener
{
    @Override
    public boolean onPreferenceClick(Preference preference) 
    {
        try
        {
            Intent launchIntent = new Intent(Intent.ACTION_VIEW);
            launchIntent.setData(Uri.parse(getString(R.string.market_search_url)));
            startActivity(launchIntent);
        }
        catch (ActivityNotFoundException e)
        {
            Toast.makeText(AppSwipePreferences.this, R.string.error_launching_app, Toast.LENGTH_SHORT).show();
        }

        return true;
    }
}

My R.string.market_search_url is defined as: market://search?q=magouyaware

I chose to put it in a try block because there are some Android phones that do not have the Android Market (they are not Google Experience devices). If the Market app can't be found then a toast message is displayed telling the user that the application couldn't be found.

Hope this helps...