用數據庫條目填充ExpendableListView

Question

我正在使用一些示例到ExpendableList，我被困在項目的最後。

我不會粘貼整個代碼，因爲沒有人會閱讀它。有些部分可能會出現問題。

適配器我認爲有問題。當我爲ListViev設置它時，我得到一個blan頁面。沒有例外，一切似乎都在起作用。活動開始，但列表爲空。

片段我的活動類

adapter = new ExpandableListAdapter(this, new ArrayList<String>(), 
       new ArrayList<ArrayList<Expense>>());   

     //database cursor 
     Cursor cursor = db.SQLDb.rawQuery("SELECT "+db.EXPENSE_CATEGORY+","+db.EXPENSE_DATE+ 
       ", SUM("+db.EXPENSE_VALUE+") 'SUM' , STRFTIME('%m', "+db.EXPENSE_DATE+") \"MONTH\", STRFTIME('%Y', "+db.EXPENSE_DATE+ 
       ") \"YEAR\" FROM "+db.TABLE_EXPENSES+ " GROUP BY "+db.EXPENSE_CATEGORY+ ", MONTH, YEAR ORDER BY MONTH DESC, YEAR DESC" , null); 

    //geting values from table    
     if (cursor.moveToFirst()) { 
      do{ 

       String category = cursor.getString(cursor.getColumnIndex(db.EXPENSE_CATEGORY));    
       double sum = cursor.getFloat(cursor.getColumnIndex("SUM")); 
       String date = cursor.getString(cursor.getColumnIndex(db.EXPENSE_DATE)); 
       String month = cursor.getString(cursor.getColumnIndex("MONTH")) + " " +cursor.getString(cursor.getColumnIndex("YEAR")); ;  

//adding new object to adapter 
       adapter.addExpense(new Expense(category, sum, date, month)); 


      }while (cursor.moveToNext()); 
     }  

//seting the adapter for ListView 
    listView.setAdapter(adapter); 

片段ExpendalbeListAdapter類的

公共類ExpandableListAdapter擴展BaseExpandableListAdapter {

private Context context; 
private ArrayList<String> groups; 
private ArrayList<ArrayList<Expense>> children; 

public ExpandableListAdapter(Context context, ArrayList<String> groups, ArrayList<ArrayList<Expense>> children) { 
    this.context = context; 
    this.groups = groups; 
    this.children = children; 
} 

public void addExpense(Expense expense) { 
    if (!groups.contains(expense.getMonth())) { 
     groups.add(expense.getMonth()); 
    } 
    int index = groups.indexOf(expense.getMonth()); 
    if (children.size() < index + 1) { 
     children.add(new ArrayList<Expense>()); 
    } 
    children.get(index).add(expense); 
} 

// Return a child view. You can load your custom layout here. 
@Override 
public View getChildView(int groupPosition, int childPosition, 
     boolean isLastChild, View convertView, ViewGroup parent) { 
    Expense expense = (Expense) getChild(groupPosition, childPosition); 
    if (convertView == null) { 
     LayoutInflater infalInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
     convertView = infalInflater.inflate(R.layout.summary_child, null); 
    } 
    TextView tv = (TextView) convertView.findViewById(R.id.tvChild); 
    tv.setText(" " + expense.getCategory());   

    return convertView; 
} 

@Override 
public View getGroupView(int groupPosition, boolean isExpanded, 
     View convertView, ViewGroup parent) { 
    String group = (String) getGroup(groupPosition); 
    if (convertView == null) { 
     LayoutInflater infalInflater = (LayoutInflater) context 
     .getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
     convertView = infalInflater.inflate(R.layout.summary_group, null); 
    } 
    TextView tv = (TextView) convertView.findViewById(R.id.tvGroup); 
    tv.setText(group); 
    return convertView; 
} 

費用類

public class Expense { 
     private String category; 
     private double value; 
     private String date; 
     private String month; 

     public Expense(String category, double value, String date, String month){ 
      this.category = category; 
      this.value = value; 
      this.date = date; 
      this.month = month; 
     } 
    } 

佈局

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
     android:orientation="vertical" android:layout_width="fill_parent" 
     android:layout_height="fill_parent"> 
     <ExpandableListView android:id="@+id/listView" 
       android:layout_width="fill_parent" android:layout_height="fill_parent" android:scrollbars="none"></ExpandableListView> 
</LinearLayout> 

<LinearLayout android:id="@+id/LinearLayout01" 
     android:layout_width="fill_parent" android:layout_height="45dip" 
     xmlns:android="http://schemas.android.com/apk/res/android"> 
     <ImageView android:id="@+id/ImageView01" android:src="@drawable/icon" 
       android:layout_height="40dip" android:layout_width="40dip" android:layout_marginLeft="40dip"></ImageView> 
     <TextView android:id="@+id/tvGroup" android:layout_width="fill_parent" 
       android:layout_height="45dip" android:text="Groups" android:gravity="center_vertical|right" 
       android:paddingLeft="5dip" android:paddingRight="5dip" 
       android:textColor="#ffffffff" android:textStyle="bold" 
       android:textSize="17dip"></TextView> 
</LinearLayout> 

<LinearLayout android:id="@+id/LinearLayout01" 
     android:layout_width="fill_parent" android:layout_height="45dip" 
     xmlns:android="http://schemas.android.com/apk/res/android"> 
     <ImageView android:id="@+id/ImageView01" android:src="@drawable/icon" 
       android:layout_height="40dip" android:layout_width="40dip" android:layout_marginLeft="40dip"></ImageView> 
     <TextView android:layout_width="fill_parent" 
       android:layout_height="45dip" android:paddingLeft="5dip" 
       android:paddingRight="5dip" android:textStyle="bold" android:textSize="17dip" 
       android:gravity="center_vertical" android:id="@+id/tvChild" 
       android:text="Children" android:textColor="#ffCCCC22"></TextView> 
</LinearLayout> 

Answer 1

我錯過了在ExpendableListAdapter類的一些方法，但一般現在的工作。但是，Pepi說這不是最有效的方式，所以請自行承擔風險。

這裏是例子我跟着 http://techdroid.kbeanie.com/2010/09/expandablelistview-on-android.html