Question

这是可扩展listview的代码，其中每个grouo都有一个复选框和一个textview。有一个Select All复选框，点击它会改变所有子视图的复选框的状态，但它没有发生。有人可以解释为什么吗？

MainActivity.java

public class MainActivity extends ActionBarActivity implements OnClickListener {

     ExpandableListAdapter listAdapter;
        ExpandableListView expListView;
        List<String> listDataHeader;
        static CheckBox selectAll;
        HashMap<String, List<String>> listDataChild;

        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);

            // get the listview
            expListView = (ExpandableListView) findViewById(R.id.expandableListView1);
            selectAll=(CheckBox)findViewById(R.id.checkBox1);
            // preparing list data
            prepareListData();

            listAdapter = new ExpandableListAdapter(this, listDataHeader, listDataChild);

            // setting list adapter
            expListView.setAdapter(listAdapter);
            selectAll.setOnClickListener(this);

        }

        /*
         * Preparing the list data
         */
        private void prepareListData() {
            listDataHeader = new ArrayList<String>();
            listDataChild = new HashMap<String, List<String>>();

            // Adding child data
            listDataHeader.add("Top 250");
            listDataHeader.add("Now Showing");
            listDataHeader.add("Coming Soon..");

            // Adding child data
            List<String> top250 = new ArrayList<String>();
            top250.add("The Shawshank Redemption");
            top250.add("The Godfather");

            List<String> nowShowing = new ArrayList<String>();
            nowShowing.add("The Conjuring");
            nowShowing.add("Despicable Me 2");


            List<String> comingSoon = new ArrayList<String>();
            comingSoon.add("2 Guns");
            comingSoon.add("The Smurfs 2");


            listDataChild.put(listDataHeader.get(0), top250); // Header, Child data
            listDataChild.put(listDataHeader.get(1), nowShowing);
            listDataChild.put(listDataHeader.get(2), comingSoon);
        }

        @Override
        public void onClick(View arg0) {
            // TODO Auto-generated method stub
            CheckBox cb=(CheckBox)listAdapter.getChildView(0, 0, false, null,         null).findViewById(R.id.cb_child);
            cb.setChecked(true);
            ((BaseExpandableListAdapter) listAdapter).notifyDataSetChanged();
        }

}

ExpandableListAdapter.java

public class ExpandableListAdapter extends BaseExpandableListAdapter  {

    private Context _context;
    private List<String> _listDataHeader; // header titles
    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(final 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.child_layout, null);
        }

        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.group_layout, null);
        }

        TextView lblListHeader = (TextView) convertView
                .findViewById(R.id.textView1);
        lblListHeader.setTypeface(null, Typeface.BOLD);
        lblListHeader.setText(headerTitle);

        return convertView;
    }   

}

activity_main.xml中

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.expandablelisttest.MainActivity"
    tools:ignore="MergeRootFrame" >

    <ExpandableListView
        android:layout_marginTop="100dp"
        android:id="@+id/expandableListView1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true" >

    </ExpandableListView>

    <CheckBox
        android:id="@+id/checkBox1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:layout_marginTop="21dp"
        android:text="Select All" />

</RelativeLayout>

child_layout.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <CheckBox
        android:id="@+id/cb_child"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:layout_marginTop="18dp"
        android:text="CheckBox" 
        android:checked="false"/>

</RelativeLayout>

group_layout.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:layout_marginLeft="18dp"
        android:layout_marginTop="14dp"
        android:text="TextView" />

</RelativeLayout>

Answer 1

您不能这样做，因为您的ExpandableListAdapter只知道项目字符串而不是复选框。
您必须修改ExpandableListAdapter才能访问其中的复选框。

这可能对你有帮助---＆gt; http://www.survivingwithandroid.com/2013/01/android-expandablelistview-baseexpandablelistadapter.html。
您需要创建一个结构，其中包含列表中每个项目所需的对象。

Answer 2

方法getChildView（..）由适配器用于填充组下的可展开子视图。

我可以鼓励你创建自己的ExpandableListAdapter，它扩展自BaseExpandableListAdapter（如果你有1组= 1项，你只需使用1个arrayList和你自己的POJO对象模型）

最后，为了完整的解释，当你调用notifyDataSetChanged（）时，列表刷新视图带有适配器的数据（例子获取每个布尔值并使用那里的值进行检查或取消选中复选框）

子视图项目不令人耳目一新

2 个答案: