I've got a ListActivity that's using a CursorAdapter to draw a dataset in a table format. I originally used a TableLayout (and drew the entire table) but I was concerned that this was using too much memory (and drawing the page was slow) so I'm now investigating using a CursorAdapter.
The XML layout for the body of the activity looks like this (note the use of a HorizontalScrollView, which may be a cause):
<?xml version="1.0" encoding="UTF-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical"
android:id="@+id/layout_query_viewer">
<TextView
android:id="@+id/query_table_name"
style="@style/ActivityTitle" />
<HorizontalScrollView
android:id="@+id/hsvMainContent"
android:scrollbars="none"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<LinearLayout
android:id="@+id/llMainContent"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<LinearLayout
android:id="@+id/fixed_headers"
android:layout_width="fill_parent"
android:layout_height="wrap_content" />
<ListView
android:id="@android:id/android:list"
android:layout_width="fill_parent"
android:layout_height="fill_parent"/>
</LinearLayout>
</HorizontalScrollView>
</LinearLayout>
The CursorAdapter looks like this:
private class QueryAdapter extends CursorAdapter {
public QueryAdapter(Context context) {
super(context, null);
}
@Override
public View newView(Context context, Cursor cursor, ViewGroup parent) {
/*
* I'm deliberately not inflating here as I'm synchronizing a remote
* database, so I don't know how many columns my query will return.
*/
LinearLayout layout = new LinearLayout(context);
ViewHolder holder = new ViewHolder(cursor.getColumnCount());
layout.setTag(holder);
for (int i = 1; i < cursor.getColumnCount(); i++) {
TextView cell = new TextView(context);
holder.cells[i] = cell;
cell.setBackgroundColor(Color.WHITE);
cell.setMinimumWidth(mColumnWidths[i]);
cell.setPadding(1, 1, 1, 1);
layout.addView(cell);
}
return layout;
}
@Override
public void bindView(View view, Context context, Cursor cursor) {
ViewHolder holder = (ViewHolder)view.getTag();
for (int i = 1; i < cursor.getColumnCount(); i++) {
holder.cells[i].setText(cursor.getString(i));
}
}
}
static class ViewHolder {
TextView[] cells;
public ViewHolder(int size) {
cells = new TextView[size];
}
}
I was happy with the scrolling performance when I drew the entire table but now that I've switched to the CursorAdapter the scrolling is jerky (and I mean unacceptably jerky). The CursorAdapter approach seems logically the correct decision architecturally but unless I can fix the scroll problem then I'll have to go back to drawing the entire table.
Has anyone else experienced this or can shed some light on what I doing wrong?