mDialog = new Dialog(this, R.style.chooseUserDialogTheme);
mDialog.setTitle(R.string.choose_user);
View rootView = LayoutInflater.from(this).inflate(
    R.layout.view_simple_choose_user, null);
mDialog.setContentView(rootView);
mLinearLayoutUserList = (LinearLayout) rootView
    .findViewById(R.id.linearLayout_user_list);
mDialog.show();
mIsUserListShown = true;
DialogInterface.OnDismissListener listener = new DialogInterface.OnDismissListener() {
  @Override
  public void onDismiss(DialogInterface dialog) {
    timer.cancel();
    mIsUserListShown = false;
  }
};
mDialog.setOnDismissListener(listener);

<style name="chooseUserDialogTheme" parent="@android:style/Theme.Dialog">
    <item name="android:background">@android:color/transparent</item>
    <item name="android:textAppearance">@style/textAppearanceL</item>
    <item name="android:textColor">@android:color/white</item>
    <item name="android:windowBackground">@drawable/bg_choose_user_simple</item>
    <item name="android:popupBackground">@drawable/bg_main_activity_top_bar</item>
</style>

<?xml version="1.0" encoding="utf-8"?>
<HorizontalScrollView xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:background="@drawable/bg_main_activity_top_bar"
  android:orientation="vertical" >
  <LinearLayout
    android:id="@+id/linearLayout_user_list"
    android:layout_width="0dp"
    android:layout_height="wrap_content"
    android:orientation="horizontal" >
  </LinearLayout>
</HorizontalScrollView>