Separating Lists with Headers in Android 0.9

Read Time:3 Minute, 33 Second

Original Article: http://jsharkey.org/blog/2008/08/18/separating-lists-with-headers-in-android-09/

<!-- list_header.xml -->
<TextView
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/list_header_title"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:paddingTop="2dip"
android:paddingBottom="2dip"
android:paddingLeft="5dip"
style="?android:attr/listSeparatorTextViewStyle" />
<!-- list_item.xml -->
<TextView
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/list_item_title"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:paddingTop="10dip"
android:paddingBottom="10dip"
android:paddingLeft="15dip"
android:textAppearance="?android:attr/textAppearanceLarge"
/>

 

<!-- list_complex.xml -->
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:paddingTop="10dip"
android:paddingBottom="10dip"
android:paddingLeft="15dip"
>
<TextView
android:id="@+id/list_complex_title"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
/>
<TextView
android:id="@+id/list_complex_caption"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceSmall"
/>
</LinearLayout>

 
==============================

public class SeparatedListAdapter extends BaseAdapter {
public final Map<String,Adapter> sections = new LinkedHashMap<String,Adapter>();
public final ArrayAdapter<String> headers;
public final static int TYPE_SECTION_HEADER = 0;
public SeparatedListAdapter(Context context) {
headers = new ArrayAdapter<String>(context, R.layout.list_header);
}
public void addSection(String section, Adapter adapter) {
this.headers.add(section);
this.sections.put(section, adapter);
}
public Object getItem(int position) {
for(Object section : this.sections.keySet()) {
Adapter adapter = sections.get(section);
int size = adapter.getCount() + 1;
// check if position inside this section
if(position == 0) return section;
if(position < size) return adapter.getItem(position - 1);
// otherwise jump into next section
position -= size;
}
return null;
}
public int getCount() {
// total together all sections, plus one for each section header
int total = 0;
for(Adapter adapter : this.sections.values())
total += adapter.getCount() + 1;
return total;
}
public int getViewTypeCount() {
// assume that headers count as one, then total all sections
int total = 1;
for(Adapter adapter : this.sections.values())
total += adapter.getViewTypeCount();
return total;
}
public int getItemViewType(int position) {
int type = 1;
for(Object section : this.sections.keySet()) {
Adapter adapter = sections.get(section);
int size = adapter.getCount() + 1;
// check if position inside this section
if(position == 0) return TYPE_SECTION_HEADER;
if(position < size) return type + adapter.getItemViewType(position - 1);
// otherwise jump into next section
position -= size;
type += adapter.getViewTypeCount();
}
return -1;
}
public boolean areAllItemsSelectable() {
return false;
}
public boolean isEnabled(int position) {
return (getItemViewType(position) != TYPE_SECTION_HEADER);
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
int sectionnum = 0;
for(Object section : this.sections.keySet()) {
Adapter adapter = sections.get(section);
int size = adapter.getCount() + 1;
// check if position inside this section
if(position == 0) return headers.getView(sectionnum, convertView, parent);
if(position < size) return adapter.getView(position - 1, convertView, parent);
// otherwise jump into next section
position -= size;
sectionnum++;
}
return null;
}
@Override
public long getItemId(int position) {
return position;
}
}
=============================
public class ListSample extends Activity {
public final static String ITEM_TITLE = "title";
public final static String ITEM_CAPTION = "caption";
public Map<String,?> createItem(String title, String caption) {
Map<String,String> item = new HashMap<String,String>();
item.put(ITEM_TITLE, title);
item.put(ITEM_CAPTION, caption);
return item;
}
@Override
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
List<Map<String,?>> security = new LinkedList<Map<String,?>>();
security.add(createItem("Remember passwords", "Save usernames and passwords for Web sites"));
security.add(createItem("Clear passwords", "Save usernames and passwords for Web sites"));
security.add(createItem("Show security warnings", "Show warning if there is a problem with a site's security"));
// create our list and custom adapter
SeparatedListAdapter adapter = new SeparatedListAdapter(this);
adapter.addSection("Array test", new ArrayAdapter<String>(this,
R.layout.list_item, new String[] { "First item", "Item two" }));
adapter.addSection("Security", new SimpleAdapter(this, security, R.layout.list_complex,
new String[] { ITEM_TITLE, ITEM_CAPTION }, new int[] { R.id.list_complex_title, R.id.list_complex_caption }));
ListView list = new ListView(this);
list.setAdapter(adapter);
this.setContentView(list);
}
}

 

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