我正在尝试制作自定义 ExpandableListView，但它总是给出NullPointException。我试过调试它，它总是在myExpandableList.setAdapter(listAdapter)崩溃
我搜索了其他解决方案，在“ ManagerListActivity.this ”表单中发送上下文，而“ this ”表单没有帮助。
代码示例：
公共类 ManagerListActivity 扩展 SherlockActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_manager_list);
// Get the ExpandableListView
ExpandableListView managerList = (ExpandableListView) findViewById(R.id.list_manager);
ManagerListAdapter listAdapter = new ManagerListAdapter(ManagerListActivity.this);
ArrayList<Subordinate> managers = new ArrayList<Subordinate>();
ArrayList<Employee> employees = new ArrayList<Employee>();
ArrayList<String> listDataHeader = new ArrayList<String>();
HashMap<String, List<String>> listDataChild = new HashMap<String, List<String>>();
// 我跳过了创建经理和员工的部分
for (int i = 0; i < managers.size(); i++) {
// Name the headers
listDataHeader.add(managers.get(i).getFirstName());
List<String> childList = new ArrayList<String>();
for (int j = 0; j < managers.get(i).getProjects().size(); j++) {
// Name the children
childList.add(managers.get(i).getProjects().get(j)
.getProjectName());
}
listDataChild.put(listDataHeader.get(i), childList);
}
listAdapter = new ManagerListAdapter(this, managers, listDataChild,
employees);
managerList.setAdapter(listAdapter);
}
现在适配器：
公共类 ManagerListAdapter 扩展 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;
private ArrayList<Subordinate> managers;
private ArrayList<Employee> employees;
String phone = "";
public ManagerListAdapter(Context context, ArrayList<Subordinate> managers,
HashMap<String, List<String>> listDataChild,
ArrayList<Employee> employees) {
this.context = context;
for (int i = 0; i < managers.size(); i++) {
_listDataHeader.add(managers.get(i).getFirstName());
}
this._listDataChild = listDataChild;
this.employees = employees;
}
@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_manager_child,
null);
}
TextView txtListChild = (TextView) convertView
.findViewById(R.id.manager_child);
txtListChild.setText(childText);
return convertView;
}
@Override
public View getGroupView(int pos, boolean isExpanded, View view,
ViewGroup parent) {
if (view == null) {
LayoutInflater infalInflater = (LayoutInflater) this.context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
view = infalInflater.inflate(R.layout.list_manager_item, null);
}
TextView lblListHeader = (TextView) view
.findViewById(R.id.manager_firstname);
lblListHeader.setTypeface(null, Typeface.BOLD);
lblListHeader.setText(managers.get(pos).getFirstName());
// Use the holder to pass data to the call button
RowViewHolder holder = new RowViewHolder();
holder.callImg = (ImageView) view.findViewById(R.id.gl_call);
holder.callImg.setOnClickListener(callListener);
view.setTag(holder);
phone = employees.get(pos).getContact();
return view;
}
// Call button handling
private OnClickListener callListener = new OnClickListener() {
@Override
public void onClick(View v) {
try {
Intent i = new Intent(Intent.ACTION_CALL);
i.setData(Uri.parse("tel:" + phone));
context.startActivity(i);
} catch (Exception e) {
e.printStackTrace();
}
}
};
protected static class RowViewHolder {
public ImageView callImg;
}
当然，我还实现了 BaseExpandableListAdapter 需要的所有其他必需方法。
任何帮助，将不胜感激。
更新：
Logcat 提取：
11-06 16:13:46.283: E/AndroidRuntime(924): 致命异常: main 11-06 16:13:46.283: E/AndroidRuntime(924): java.lang.RuntimeException: 无法启动活动 ComponentInfo{com. tcs.mobility.uy.rmg/com.tcs.mobility.uy.rmg.ManagerListActivity}：java.lang.NullPointerException 11-06 16:13:46.283：E/AndroidRuntime(924)：在 android.app.ActivityThread.performLaunchActivity (ActivityThread.java:2180) 11-06 16:13:46.283: E/AndroidRuntime(924): 在 android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230) 11-06 16:13:46.283: E/AndroidRuntime (924): 在 android.app.ActivityThread.access$600(ActivityThread.java:141) 11-06 16:13:46.283: E/AndroidRuntime(924): 在 android.app.ActivityThread$H.handleMessage(ActivityThread.java :1234) 11-06 16:13:46.283: E/AndroidRuntime(924): 在 android.os.Handler.dispatchMessage(Handler.java:99) 11-06 16:13:46.283: E/AndroidRuntime(924): 在 android.os.Looper.loop(Looper.java:137) 11-06 16:13:46.283: E/AndroidRuntime(924): 在android.app.ActivityThread.main(ActivityThread.java:5039) 11-06 16:13:46.283: E/AndroidRuntime(924): 在 java.lang.reflect.Method.invokeNative(Native Method) 11-06 16:13 :46.283: E/AndroidRuntime(924): at java.lang.reflect.Method.invoke(Method.java:511) 11-06 16:13:46.283: E/AndroidRuntime(924): at com.android.internal。 os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793) 11-06 16:13:46.283: E/AndroidRuntime(924): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560) 11 -06 16:13:46.283: E/AndroidRuntime(924): at dalvik.system.NativeStart.main(Native Method) 11-06 16:13:46.283: E/AndroidRuntime(924): Caused by: java.lang. NullPointerException 11-06 16:13:46.283:E/AndroidRuntime(924): 在 com.tcs.mobility.uy.rmg.ManagerListAdapter.(ManagerListAdapter.java:63) 11-06 16:13:46.283: E/AndroidRuntime(924): 在 com.tcs.mobility。 uy.rmg.ManagerListActivity.onCreate(ManagerListActivity.java:146) 11-06 16:13:46.283: E/AndroidRuntime(924): 在 android.app.Activity.performCreate(Activity.java:5104) 11-06 16: 13:46.283: E/AndroidRuntime(924): 在 android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080) 11-06 16:13:46.283: E/AndroidRuntime(924): 在 android.app.ActivityThread.performLaunchActivity (ActivityThread.java:2144) 11-06 16:13:46.283: E/AndroidRuntime(924): ... 11 更多146) 11-06 16:13:46.283: E/AndroidRuntime(924): 在 android.app.Activity.performCreate(Activity.java:5104) 11-06 16:13:46.283: E/AndroidRuntime(924): 在android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080) 11-06 16:13:46.283: E/AndroidRuntime(924): 在 android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144) 11-06 16: 13:46.283: E/AndroidRuntime(924): ... 11 更多146) 11-06 16:13:46.283: E/AndroidRuntime(924): 在 android.app.Activity.performCreate(Activity.java:5104) 11-06 16:13:46.283: E/AndroidRuntime(924): 在android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080) 11-06 16:13:46.283: E/AndroidRuntime(924): 在 android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144) 11-06 16: 13:46.283: E/AndroidRuntime(924): ... 11 更多