将自定义ArrayAdapter添加到可扩展列表视图

Question

我尝试在可扩展列表视图中传递我的自定义数组适配器，但是我遇到了问题空点异常。在组视图中，我传递自定义arrayadapter而不是字符串，但子视图仍然是字符串。这工作正常，直到我将String转换为我的自定义Arrayadapter并在那里放置多个视图。有一个警告显示在getchild方法中对hashmap的可疑调用，我认为这是问题所在。请帮忙

这是我的logcat

   06-02 03:08:35.971 7966-7966/me.ashishgm.expandablemenu E/AndroidRuntime: FATAL EXCEPTION: main
   Process: me.ashishgm.expandablemenu, PID: 7966
   java.lang.NullPointerException: Attempt to invoke interface method 'java.lang.Object java.util.List.get(int)' on a null object reference
 at me.ashishgm.expandablemenu.ExpandableListAdapter.getChild(ExpandableListAdapter.java:31)
 at me.ashishgm.expandablemenu.ExpandableListAdapter.getChildView(ExpandableListAdapter.java:42)
 at android.widget.ExpandableListConnector.getView(ExpandableListConnector.java:451)
 at android.widget.AbsListView.obtainView(AbsListView.java:2363)
 at android.widget.ListView.makeAndAddView(ListView.java:1970)
 at android.widget.ListView.fillDown(ListView.java:704)
 at android.widget.ListView.fillSpecific(ListView.java:1412)
 at android.widget.ListView.layoutChildren(ListView.java:1708)
 at android.widget.AbsListView.onLayout(AbsListView.java:2162)
 at android.view.View.layout(View.java:17637)
 at android.view.ViewGroup.layout(ViewGroup.java:5575)
 at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1741)
 at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1585)
 at android.widget.LinearLayout.onLayout(LinearLayout.java:1494)
 at android.view.View.layout(View.java:17637)
 at android.view.ViewGroup.layout(ViewGroup.java:5575)
 at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
 at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
 at android.view.View.layout(View.java:17637)
 at android.view.ViewGroup.layout(ViewGroup.java:5575)
 at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1741)
 at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1585)
 at android.widget.LinearLayout.onLayout(LinearLayout.java:1494)
 at android.view.View.layout(View.java:17637)
 at android.view.ViewGroup.layout(ViewGroup.java:5575)
 at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
 at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
 at com.android.internal.policy.DecorView.onLayout(DecorView.java:726)
 at android.view.View.layout(View.java:17637)
 at android.view.ViewGroup.layout(ViewGroup.java:5575)
at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:2346)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2068)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1254)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6337)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:874)
at android.view.Choreographer.doCallbacks(Choreographer.java:686)
at android.view.Choreographer.doFrame(Choreographer.java:621)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:860)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6119)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)

以下是我的可扩展适配器的代码

public class ExpandableListAdapter extends BaseExpandableListAdapter {

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

ExpandableListAdapter(Context context, List<people_detail> listDataHeader,
                      HashMap<people_detail, List<String>> listChildData) {
    this._context = context;
    this._listDataHeader = listDataHeader;
    this._listDataChild = listChildData;
}
//I think i have problem in this part and this is also showing the warning Suspicious call to HashMap

@Override
public Object getChild(int groupPosition, int childPosititon) {
    return this._listDataChild.get(this._listDataChild.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 people_detail 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) {
    people_detail headerTitle = (people_detail) 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);
    TextView checktest=(TextView) convertView.findViewById(R.id.lblListHeader2);
    TextView checkok=(TextView) convertView.findViewById(R.id.lblListHeader3);
    ImageView img_vr=(ImageView)convertView.findViewById(R.id.image_view);
    lblListHeader.setTypeface(null, Typeface.BOLD);
    lblListHeader.setText(headerTitle.getPatientName());
    checktest.setText(headerTitle.gethospitalName());
    checkok.setText(headerTitle.gettimeRequired());

    switch (groupPosition)
    {
        case 0:
            checktest.setText("Nepal");
            img_vr.setImageResource(R.drawable.ic_devices_other_black_24dp);
            break;
        case 1:
            checktest.setText("India");
            img_vr.setImageResource(R.drawable.ic_phonelink_setup_black_24dp);
            break;
        case 2:
            checktest.setText("China");
            break;
        default:
            checktest.setText("Africa");
    }

    return convertView;
}

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

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

我的mainActivity在这里

public class MainActivity extends Activity {

ExpandableListAdapter listAdapter;
ExpandableListView expListView;
List<people_detail> listDataHeader;
HashMap<people_detail, 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.lvExp);

    // preparing list data
    prepareListData();

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

    // setting list adapter
    expListView.setAdapter(listAdapter);
}

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

    // Adding child data
    listDataHeader.add(new people_detail("Top 250","Nepal","Fuck",R.drawable.ic_assignment_returned_black_24dp));
    listDataHeader.add(new people_detail("Top 250","Nepal","Fuck in the sun",R.drawable.ic_assignment_returned_black_24dp));
    listDataHeader.add(new people_detail("Navana timro","Nepal","Fuck in the sun",R.drawable.ic_assignment_returned_black_24dp));
    listDataHeader.add(new people_detail("hello hello","Nepal","Fuck in the sun",R.drawable.ic_assignment_returned_black_24dp));
    listDataHeader.add(new people_detail("Yo Jindagi ho","Nepal","Fuck in the sun",R.drawable.ic_assignment_returned_black_24dp));
    listDataHeader.add(new people_detail("Top 250","Nepal","Khai k vanne ",R.drawable.ic_assignment_returned_black_24dp));
    listDataHeader.add(new people_detail("you are beast","Nepal","k navanne",R.drawable.ic_assignment_returned_black_24dp));


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

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


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

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



}

}

我的人员详细课程在这里

public class people_detail {

// Name of the Android version (e.g. Gingerbread, Honeycomb, Ice Cream Sandwich)
private String mpatientName;

// Android version number (e.g. 2.3-2.7, 3.0-3.2.6, 4.0-4.0.4)
private String mhospitalName;

private String timeRequired;

// Drawable resource ID
private int mImageResourceId;

/*
* Create a new AndroidFlavor object.
*
* @param vName is the name of the Android version (e.g. Gingerbread)
* @param vNumber is the corresponding Android version number (e.g. 2.3-2.7)
* @param image is drawable reference ID that corresponds to the Android version
* */
public people_detail(String vpatientName, String vhospitalName, String vtimeRequired , int imageResourceId)
{
    mpatientName=vpatientName;
    mhospitalName=vhospitalName;
    timeRequired=vtimeRequired;
    mImageResourceId = imageResourceId;
}

/**
 * Get the name of the Android version
 */
public String getPatientName() {
    return mpatientName ;
}

/**
 * Get the Android version number
 */
public String gethospitalName() {
    return mhospitalName;
}

/**
 * Get the hospital Name
 */
public String gettimeRequired() {
    return timeRequired;
}

/**
 * Get the image resource ID
 */
public int getImageResourceId() {
    return mImageResourceId;
}

}

Answer 1

它是this._listDataChild.get(groupPosition)处的空指针异常，您声明groupPosition是int但从未给它赋值。