I think what you're trying to do should be done with multiple Activities. If you're learning Android, understanding Activities is something you're going to have to tackle. Trying to write a whole app with just one Activity will end up being a lot more difficult. Read this article to get yourself started, then you should end up with something more like this:
View.OnClickListener handler = new View.OnClickListener(){
public void onClick(View v) {
switch (v.getId()) {
case R.id.DownloadView:
// doStuff
startActivity(new Intent(ThisActivity.this, DownloadActivity.class));
break;
case R.id.AppView:
// doStuff
startActivity(new Intent(ThisActivity.this, AppActivity.class));
break;
}
}
};
findViewById(R.id.DownloadView).setOnClickListener(handler);
findViewById(R.id.AppView).setOnClickListener(handler);