Question

我有一个可扩展的ListView，但我遇到了两个问题。 Q1。如果标题不包含任何子项我想隐藏/从列表中删除它。为此，我有getGroupView方法。

if ( getChildrenCount( groupPosition ) == 0 ) 
{
   convertView.setVisibility(View.GONE);
}

假设我有10个标题和标题3,5，而且8没有任何子节点。当我使用上面的代码时它会隐藏3,5,8th标题，但问题是它留下了空白区域，它看起来不像列表。那么任何想法如何让它看起来像一个列表？

Q2。我想在标题没有任何子节点时显示一条Toast消息，说“数据不可用”。为此，我在getGroupView方法中使用了以下代码，

     convertView.setOnClickListener(new OnClickListener() {

                @Override
                public void onClick(View arg0) {
                    // TODO Auto-generated method stub
                    if ( getChildrenCount( groupPosition ) == 0 )
                        Toast.makeText(_context, "No data available", Toast.LENGTH_SHORT).show();

                }
            });

这显示了toast消息，但问题在于 - 当我点击它们时，有孩子的标题不会扩展。如何解决这个问题？

以下是填充数据集的代码

listDataHeader = new ArrayList<String>();
listDataChild = new HashMap<String, List<String>>();

    listDataHeader.add(dayName_first);
    listDataHeader.add(dayName_second);
    listDataHeader.add(dayName_third);
    listDataHeader.add(dayName_fourth);
    listDataHeader.add(dayName_fifth);
    listDataHeader.add(dayName_sixth);
    listDataHeader.add(dayName_seventh);

    firstDay = checkEmpty(firstDay);  // Function to check whether the list is empty or not. Do I need to check each list here and add or somewhere else?
    listDataChild.put(listDataHeader.get(0), firstDay);
    listDataChild.put(listDataHeader.get(1), secondDay);
    listDataChild.put(listDataHeader.get(2), thirdDay);
    listDataChild.put(listDataHeader.get(3), fourthDay);
    listDataChild.put(listDataHeader.get(4), fifthDay);
    listDataChild.put(listDataHeader.get(5), sixthDay);
    listDataChild.put(listDataHeader.get(6), seventhDay);

    listAdapter = new StaffExpandableListAdapter(this, listDataHeader,
            listDataChild);
    llExpandable.invalidateViews();

    llExpandable.setAdapter(listAdapter);

Answer 1

让我先回答第二个问题，因为那样更直接。

问题在于，当您设置自定义单击侦听器时，它会覆盖列表中的默认侦听器。

所以，你需要做的是先检查子计数。如果计数为零，则只添加监听器。

if ( getChildrenCount( groupPosition ) == 0 )
 convertView.setOnClickListener(new OnClickListener() {

                @Override
                public void onClick(View arg0) {
                   Toast.makeText(_context, "No data available", Toast.LENGTH_SHORT).show();

                }
            });

现在，回到第一个问题。我假设您有一个数据集，您可以在其中存储所有元素。在为可扩展列表视图创建适配器之前，循环遍历数据集并删除所有不具有子项的元素。在此之后，从数据集创建适配器。

Answer 2

试试此代码

   import java.util.HashMap;
   import java.util.List;

   import android.content.Context;
   import android.graphics.Typeface;
   import android.view.LayoutInflater;
   import android.view.View;
   import android.view.ViewGroup;
   import android.widget.BaseExpandableListAdapter;
   import android.widget.TextView;

   public class ExpandableListAdapter extends BaseExpandableListAdapter {

private Context _context;
private List<String> _listDataHeader; // header titles
// child data in format of header title, child title
private HashMap<String, List<String>> _listDataChild;

public ExpandableListAdapter(Context context, List<String> listDataHeader,
        HashMap<String, List<String>> listChildData) {
    this._context = context;
    this._listDataHeader = listDataHeader;
    this._listDataChild = listChildData;
}

@Override
public Object getChild(int groupPosition, int childPosititon) {
    return this._listDataChild.get(this._listDataHeader.get(groupPosition))
            .get(childPosititon);
}

@Override
public long getChildId(int groupPosition, int childPosition) {
    return childPosition;
}

@Override
public View getChildView(int groupPosition, final int childPosition,
        boolean isLastChild, View convertView, ViewGroup parent) {

    final String childText = (String) getChild(groupPosition, childPosition);

    if (convertView == null) {
        LayoutInflater infalInflater = (LayoutInflater) this._context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        convertView = infalInflater.inflate(R.layout.list_item, null);
    }

    TextView txtListChild = (TextView) convertView
            .findViewById(R.id.lblListItem);

    txtListChild.setText(childText);
    return convertView;
}

@Override
public int getChildrenCount(int groupPosition) {
    return this._listDataChild.get(this._listDataHeader.get(groupPosition))
            .size();
}

@Override
public Object getGroup(int groupPosition) {
    return this._listDataHeader.get(groupPosition);
}

@Override
public int getGroupCount() {
    return this._listDataHeader.size();
}

@Override
public long getGroupId(int groupPosition) {
    return groupPosition;
}

@Override
public View getGroupView(int groupPosition, boolean isExpanded,
        View convertView, ViewGroup parent) {
    String headerTitle = (String) getGroup(groupPosition);
    if (convertView == null) {
        LayoutInflater infalInflater = (LayoutInflater) this._context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        convertView = infalInflater.inflate(R.layout.list_group, null);
    }

    TextView lblListHeader = (TextView) convertView
            .findViewById(R.id.lblListHeader);
    lblListHeader.setTypeface(null, Typeface.BOLD);
    lblListHeader.setText(headerTitle);

    return convertView;
}

@Override
public boolean hasStableIds() {
    return false;
}

@Override
public boolean isChildSelectable(int groupPosition, int childPosition) {
    return true;
}

}

使用以下链接http://www.androidhive.info/2013/07/android-expandable-list-view-tutorial/如果有用，请接受ans ...给我信用

Android中的可扩展列表视图

2 个答案: