我为我的英语道歉但是用谷歌翻译过来。我的应用程序需要帮助,我使用ExpandableListView
3个不同的组,2个组使用静态项目,并使用包含项目的组应该在AsyncTask
之后更新。
当我第一次运行应用程序时,具有动态项目的组为空,而第二次是可见。我如何实时更新动态项目?
我的应用程序是以这种方式构建的,我有一个实例化ExpandableListView
的主要活动,另一个执行AsyncTask
的类,然后我有一个扩展BaseExpandableListAdapter
的类。我尝试在主要活动中使用方法notifyDataSetChanged()
,但它不起作用。
我希望我足够清楚,我希望答案同样清楚,不幸的是我一直在互联网上,但找不到我想要的答案。在此先感谢那些能帮助我的人。
MainActivity.java
public class MainActivity extends Activity {
private ExpandableListView expListView;
private ExpandableListAdapter listAdapter;
List<String> listDataHeader;
HashMap<String, List<String>> listDataChild;
static ArrayList<String> allResults = new ArrayList<String>(5);
@Override
public void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
prepareListData();
expListView = (ExpandableListView) findViewById(R.id.explist);
listAdapter = new ExpandableListAdapter(this, listDataHeader, listDataChild);
expListView.setAdapter(listAdapter);
}
private void prepareListData() {
GetResults getResults = new GetResults();
getResults.execute();
allResults = getResults.getAllResults();
listDataHeader = new ArrayList<String>();
listDataChild = new HashMap<String, List<String>>();
/** header visualization */
listDataHeader.add(getString(R.string.drawer_title_advanced));
listDataHeader.add(getString(R.string.drawer_title_visualization));
listDataHeader.add(getString(R.string.drawer_title_route));
// Adding child data
List<String> settings = new ArrayList<String>();
List<String> visualization = new ArrayList<String>();
List<String> routes = new ArrayList<String>();
items1.add("Group 1");
items2.add("Group 2");
for (int i = 0; i < allResults.size(); i++) {
items3.add(allResults.get(i));
}
listDataChild.put(listDataHeader.get(0), items1);
listDataChild.put(listDataHeader.get(1), items2);
listDataChild.put(listDataHeader.get(2), items3);
}
}
GetResults.java
public class GetResults extends AsyncTask<String, Void, String> {
private static ArrayList<String> allResults = new ArrayList<String>(5);
@Override
protected String doInBackground(String... params) {
//
}
@Override
protected void onPostExecute(String res) {
JSONArray JsonArrayResult = new JSONArray(res);
for (int i = 0; i < JsonArrayResult.length(); i++) {
JSONObject JsonObjectResult = JsonArrayResult.getJSONObject(i);
allResults.add(JsonObjectResult.getString("results"););
}
}
public ArrayList<String> getAllResults() {
return allResults;
}
}
ExpandableListAdapter.java
public class ExpandableListAdapter extends BaseExpandableListAdapter {
private Context _context;
private List<String> _listDataHeader; // header titles
private HashMap<String, List<String>> _listDataChild;
private LayoutInflater infalInflater;
public ExpandableListAdapter(Context context,
List<String> listDataHeader,
HashMap<String, List<String>> listChildData) {
this._context = context;
this._listDataHeader = listDataHeader;
this._listDataChild = listChildData;
}
@Override
public int getGroupCount() {
// TODO Auto-generated method stub
return this._listDataHeader.size();
}
@Override
public int getChildrenCount(int groupPosition) {
// TODO Auto-generated method stub
return this._listDataChild.get(this._listDataHeader.get(groupPosition))
.size();
}
@Override
public Object getGroup(int groupPosition) {
// TODO Auto-generated method stub
return this._listDataHeader.get(groupPosition);
}
@Override
public Object getChild(int groupPosition, int childPosition) {
return this._listDataChild.get(this._listDataHeader.get(groupPosition))
.get(childPosition);
}
@Override
public long getGroupId(int groupPosition) {
// TODO Auto-generated method stub
return 3;
}
@Override
public long getChildId(int groupPosition, int childPosition) {
// TODO Auto-generated method stub
return childPosition;
}
@Override
public boolean hasStableIds() {
// TODO Auto-generated method stub
return false;
}
@Override
public View getGroupView(int groupPosition, boolean isExpanded,
View convertView, ViewGroup parent) {
String headerTitle = (String) getGroup(groupPosition);
View v = null;
if (convertView != null)
v = convertView;
else {
// if (convertView == null) {
LayoutInflater infalInflater = (LayoutInflater) this._context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
v = infalInflater.inflate(R.layout.list_group1, null);
}
TextView lblListHeader = (TextView) v.findViewById(R.id.lblListHeader);
// lblListHeader.setTypeface(null, Typeface.BOLD);
lblListHeader.setText(headerTitle);
return v;
}
@Override
public View getChildView(int groupPosition, int childPosition,
boolean isLastChild, View convertView, ViewGroup parent) {
View v = null;
infalInflater = (LayoutInflater) this._context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
if (convertView == null) {
if (groupPosition == 0) {
v = infalInflater.inflate(R.layout.adv_item, null);
}
if (groupPosition == 1) {
v = infalInflater.inflate(R.layout.visual_item, null);
}
if (groupPosition == 2) {
v = infalInflater.inflate(R.layout.routes_item, null);
}
} else {
v = convertView;
}
return v;
}
}
答案 0 :(得分:1)
从AsyncTask中删除getAllResults();
。这是个坏主意。在onCreate
开始你的asynctask。然后在onPostExecute中构建列表并设置适配器。
所以几乎所有的代码都应该在onPostExecute中完成。