Stuck here for more than a week, but still unable to decide! I have expandable listViewwhere the data was obtained from SQLiteand installed on expListAdapter. As soon as the arrow is pressed, two children will be displayed on it.
AddMonthlyExpenses
public class AddMonthlyExpenses extends AppCompatActivity {
ArrayList<ListObj> groupList= new ArrayList<ListObj>();;
List<String> childList;
Map<ListObj, List<String>> laptopCollection;
ExpandableListView listview;
ExpandableListAdapter expListAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.add_monthly_expenses);
laptopCollection = new LinkedHashMap<ListObj, List<String>>();
listview = (ExpandableListView) findViewById(R.id.exlistView);
expListAdapter = new ExpandableListAdapter(getApplication(), groupList, laptopCollection);
listview.setAdapter(expListAdapter);
retrieveList(name);
}
public void retrieveList(String name) {
database = mdb.getReadableDatabase();
Cursor cursor = database.rawQuery("SELECT * FROM " + MyDatabaseHelper.TABLE__TASK + " WHERE Name = ? ", new String[]{name}, null);
if (cursor != null && cursor.getCount() > 0) {
while (cursor.moveToNext()) {
groupList = new ArrayList<ListObj>();
int iD = cursor.getInt(cursor.getColumnIndex("ID"));
String month = cursor.getString(cursor.getColumnIndex("Month"));
double budget = cursor.getDouble(cursor.getColumnIndex("Budget"));
groupList.add(new ListObj(iD,month,budget));
if (expListAdapter != null) {
expListAdapter.add(iD, month, budget);
createCollection();
listview.setAdapter(expListAdapter);
}
}
}
}
private void createCollection() {
String[] options = {"Edit","Delete"};
for (ListObj laptop : groupList) {
loadChild(options);
laptopCollection.put(laptop, childList);
}
}
private void loadChild(String[] laptopModels) {
childList = new ArrayList<String>();
for (String model : laptopModels)
childList.add(model);
}
}
ExpandableListAdapter
public class ExpandableListAdapter extends BaseExpandableListAdapter {
private Context context;
Map<ListObj, List<String>> laptopCollections;
private ArrayList<ListObj> laptops;
double used = 0;
private LayoutInflater mInflater;
public ExpandableListAdapter(Context context, ArrayList<ListObj> laptops, Map<ListObj, List<String>> laptopCollections) {
this.context = context;
this.laptopCollections = laptopCollections;
this.laptops = laptops;
mInflater = LayoutInflater.from(context);
}
public Object getChild(int groupPosition, int childPosition) {
if (laptopCollections.get(laptops.get(groupPosition)).get(childPosition) != null && !laptopCollections.get(laptops.get(groupPosition)).get(childPosition).isEmpty()) {
return laptopCollections.get(laptops.get(groupPosition)).get(childPosition);
}
return 1;
}
public void add(int id, String month, double budget) {
String[] splited = month.split("\\s+");
ListObj obj = new ListObj(id, month, budget);
obj.setYear(splited[1]);
obj.setMonth(splited[0]);
obj.setBudget(budget);
obj.setID(id);
laptops.add(obj);
this.notifyDataSetChanged();
}
public long getChildId(int groupPosition, int childPosition) {
return childPosition;
}
public int getCount() {
return laptops.size();
}
public ListObj getItem(int position) {
return laptops.get(position);
}
public View getChildView(final int groupPosition, final int childPosition,
boolean isLastChild, View convertView, ViewGroup parent) {
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
final String laptop = (String) getChild(groupPosition, childPosition);
if (convertView == null) {
convertView = inflater.inflate(R.layout.child_item, null);
}
TextView edit = (TextView) convertView.findViewById(R.id.textEdit);
edit.setText(laptop);
return convertView;
}
public int getChildrenCount(int groupPosition) {
if (laptopCollections.get(laptops.get(groupPosition)) != null && ! laptopCollections.get(laptops.get(groupPosition)).isEmpty()) {
return laptopCollections.get(laptops.get(groupPosition)).size();
}
return 1;
}
public Object getGroup(int groupPosition) {
return laptops.get(groupPosition);
}
public int getGroupCount() {
return this.laptops.size();
}
public long getGroupId(int groupPosition) {
return groupPosition;
}
public View getGroupView(int groupPosition, boolean isExpanded,
View convertView, ViewGroup parent) {
ExpensesAdapter.ViewHolder holder = null;
if (convertView == null) {
convertView = mInflater.inflate(R.layout.expenses_adapter, null);
holder = new ExpensesAdapter.ViewHolder();
holder.month = (TextView) convertView.findViewById(R.id.textMonth);
holder.budget = (TextView) convertView.findViewById(R.id.textAmount);
holder.year = (TextView) convertView.findViewById(R.id.textYear);
convertView.setTag(holder);
} else {
holder = (ExpensesAdapter.ViewHolder) convertView.getTag();
}
holder.month.setText(laptops.get(groupPosition).getMonth());
holder.budget.setText(String.format("%.2f", laptops.get(groupPosition).getBudget()));
holder.year.setText(laptops.get(groupPosition).getYear());
return convertView;
}
public boolean hasStableIds() {
return true;
}
public boolean isChildSelectable(int groupPosition, int childPosition) {
return true;
}
}
Error
10-26 00: 03: 57.114 23612-23612/com.example.tony.monthlyexpenses E/AndroidRuntime: FATAL EXCEPTION: main java.lang.NullPointerException com.example.tony.monthlyexpenses.adapter.ExpandableListAdapter.getChild(ExpandableListAdapter.java:42) com.example.tony.monthlyexpenses.adapter.ExpandableListAdapter.getChildView(ExpandableListAdapter.java:87) android.widget.ExpandableListConnector.getView(ExpandableListConnector.java:451) android.widget.AbsListView.obtainView(AbsListView.java:2232) android.widget.ListView.makeAndAddView(ListView.java:1849) android.widget.ListView.fillDown(ListView.java:678) android.widget.ListView.fillSpecific(ListView.java:1339)
" "
debug, !
https://github.com/wseng92/MonthlyExpenses