HorizontalScrollView won't scroll - android-layout

Question

I'm having problem with HorizontalScrollView, I've set the child layout (LinearLayout) to 2000dp, but still won't scroll. I set the content programmatically.
This is my Activity Layout
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".AktifitasUtama" >
<HorizontalScrollView
android:id="#+id/scroll_album_holder"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_margin="5dp"
android:fillViewport="true">
<LinearLayout
android:id="#+id/album_holder"
android:layout_width="2000dp"
android:layout_height="wrap_content"
android:orientation="horizontal"></LinearLayout>
</HorizontalScrollView>
<GridView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/thumbnail_holder"
android:numColumns="auto_fit"
android:gravity="center"
android:columnWidth="180dp"
android:verticalSpacing="10dp"
android:horizontalSpacing="10dp"
android:stretchMode="columnWidth"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</RelativeLayout>
This is my Adapter Layout
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:padding="5dp" >
<ImageView
android:id="#+id/grid_item_image"
android:layout_width="fill_parent"
android:layout_height="160dp"
android:layout_marginRight="160dp" >
</ImageView>
<TextView
android:id="#+id/grid_item_label"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#+id/label"
android:layout_marginTop="5dp"
android:textSize="15sp"
android:layout_below="#id/grid_item_image"
android:layout_centerHorizontal="true">
</TextView>
</RelativeLayout>
This is my Activity class
public class AktifitasUtama extends SherlockActivity {
Session session;
HorizontalScrollView scroll_album_holder;
LinearLayout album_holder;
List<String> album_label = new ArrayList<String>();
#Override
protected void onCreate(Bundle savedInstanceState) {
requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS);
super.onCreate(savedInstanceState);
setContentView(R.layout.aktifitas_utama);
if (Build.VERSION.SDK_INT < Build.VERSION_CODES.ICE_CREAM_SANDWICH) {
Drawable ab = getResources().getDrawable(R.drawable.header);
getSupportActionBar().setBackgroundDrawable(ab);
}
setSupportProgressBarIndeterminateVisibility(true);
getSupportActionBar().setHomeButtonEnabled(false);
getSupportActionBar().setDisplayHomeAsUpEnabled(false);
session = new Session(getApplicationContext());
scroll_album_holder = (HorizontalScrollView) findViewById(R.id.scroll_album_holder);
album_holder = (LinearLayout) findViewById(R.id.album_holder);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
MenuInflater inflater = getSupportMenuInflater();
inflater.inflate(R.menu.aktifitas_utama, menu);
return (super.onCreateOptionsMenu(menu));
}
#Override
protected void onResume(){
super.onResume();
scroll_album_holder.setVisibility(View.GONE);
if(session.is_login()){
fill_album();
} else {
startActivity(new Intent(getApplicationContext(), AktifitasMasuk.class));
finish();
}
}
public void fill_album(){
album_label.clear();
int i = 2;
if(i==1){
album_label.add("Photo From Camera");
} else if (i==2){
album_label.add("Photo From Camera");
album_label.add("Album 1");
album_label.add("Album 2");
album_label.add("Album 3");
album_label.add("Album 4");
album_label.add("Album 5");
album_label.add("Album 6");
} else if(i==3) {
album_label.add("Album 1");
album_label.add("Album 2");
album_label.add("Album 3");
album_label.add("Album 4");
album_label.add("Album 5");
album_label.add("Album 6");
}
if(!album_label.isEmpty()){
scroll_album_holder.setVisibility(View.VISIBLE);
for(int j=0;j<album_label.size();j++){
album_holder.addView(set_album(album_label.get(j)));
}
}
}
private View set_album(String label){
LayoutInflater inflater = (LayoutInflater) getApplicationContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View album = inflater.inflate(R.layout.grid, null, false);
ImageView grid_item_image = (ImageView) album.findViewById(R.id.grid_item_image);
TextView grid_item_label = (TextView) album.findViewById(R.id.grid_item_label);
Drawable grid_image = getResources().getDrawable(R.drawable.custom_menu_archive);
grid_item_image.setImageDrawable(grid_image);
grid_item_label.setText(label);
return album;
}
}
So, what do you think? any advice?