我有一个使用自定义适配器填充列表视图的 android 应用程序。此适配器将部分添加到带有标题的列表视图中。该适配器如下图所示:
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;
}
}
然后由以下代码调用:
SeparatedListAdapter adapter;
public Map<String,?> createItem(String name) {
Map<String,String> item = new HashMap<String,String>();
item.put(ITEM_VALUE, name);
return item;
}
List<Map<String,?>> item = new LinkedList<Map<String,?>>();
item.add(createItem("value"));
adapter.addSection("Header", new SimpleAdapter(this, item, R.layout.list_item, new String[] { "value" }, new int[] { R.id.lblValue }));
listview.setAdapter(adapter);
现在直到最近,我的list_header
xml 文件还有一个TextView
根元素。在这一点上,它工作得很好。但后来我想扩展标题以包含多个视图。的新根元素list_header
现在是RelativeLayout
.
现在,当我尝试开始活动时,出现以下异常: IllegalStateException: ArrayAdapter requires the resource ID to be a Text View
. 我理解这个错误,但由于我对 Android 比较陌生,我不确定如何解决这个问题。如何修改我的适配器以处理包含 aRelativeLayout
作为根元素而不是 a 的标头TextView
?
编辑:我相信答案在于适配器的构造方法?