notifyDataSetChanged（）無法更新適配器onClick

Question

我正在ExpandableListViews上關注本教程 。 我希望我的實現顯示點擊按鈕后添加的新值。 但是，我沒有嘗試過。 除了嘗試使用notifyDataSetChanged（）之外，我還嘗試了notifyDataSetInvalidated（）並實例化一個新的適配器，這在類似的文章中有所建議。 未顯示的新數據在我的onClick方法下。

關於修復的任何建議嗎？

public class ClassesFragment extends Fragment implements OnClickListener {
private View v;

 Integer term;
 String termSelection;

 ListView myList;
 EditText editText1;
 Spinner spinner;

 MyExpandableListAdapter adapter;
 ExpandableListView listView;

 SparseArray<Group> groups = new SparseArray<Group>();

 Group fall2013 = new Group("Fall 2013");
 Group winter2014 = new Group("Winter 2014");
 Group spring2014 = new Group("Spring 2014");
 Group summer2014 = new Group("Summer 2014");


@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    v = inflater.inflate(R.layout.fragment_classes, container, false);

    editText1 = (EditText) v.findViewById(R.id.editText1);

    Spinner spinner = (Spinner) v.findViewById(R.id.spinner1);
    spinner.setOnItemSelectedListener(new SpinnerItemSelectedListener());



    Button add = (Button) v.findViewById(R.id.button1);
    add.setOnClickListener(this);

    createData();
    listView = (ExpandableListView) v.findViewById(R.id.expandableListView1);
    adapter = new MyExpandableListAdapter(getActivity(), groups);
    listView.setAdapter(adapter);
    return v;              
}

public void createData() {      
    groups.append(0, fall2013);
    groups.append(1, winter2014);
    groups.append(2, spring2014);
    groups.append(3, summer2014);

}

@SuppressWarnings("boxing")
public void onClick(View v) {
    switch (v.getId()) {           
        case R.id.button1:                  

            Integer crn = Integer.parseInt(editText1.getText().toString());
            editText1.setText("");

            if (termSelection.toString() == "Fall 2013") {                      

                fall2013.children.add(crn.toString());
                adapter.notifyDataSetChanged();
            }

            break;

            case R.id.button2:
                Toast.makeText(getActivity(), "Clicked on delete button", Toast.LENGTH_LONG).show();
                break;  

        }
   }


   public class SpinnerItemSelectedListener implements OnItemSelectedListener {
        public void onItemSelected(AdapterView<?> parent, View view, int pos, long id) {
            termSelection = parent.getItemAtPosition(pos).toString();
        }

        public void onNothingSelected(AdapterView parent) {
        }
    }
}

我的自定義適配器：

public class MyExpandableListAdapter extends BaseExpandableListAdapter {

  private final SparseArray<Group> groups;
  public LayoutInflater inflater;
  public Activity activity;

  public MyExpandableListAdapter(Activity act, SparseArray<Group> groups) {
    activity = act;
    this.groups = groups;
    inflater = act.getLayoutInflater();
  }

  @Override
  public Object getChild(int groupPosition, int childPosition) {
    return groups.get(groupPosition).children.get(childPosition);
  }

  @Override
  public long getChildId(int groupPosition, int childPosition) {
    return 0;
  }

  @Override
  public View getChildView(int groupPosition, final int childPosition,
      boolean isLastChild, View convertView, ViewGroup parent) {
    final String children = (String) getChild(groupPosition, childPosition);
    TextView text = null;
    if (convertView == null) {
      convertView = inflater.inflate(R.layout.listrow_details, null);
    }
    text = (TextView) convertView.findViewById(R.id.textView1);
    text.setText(children);
    convertView.setOnClickListener(new OnClickListener() {
      @Override
      public void onClick(View v) {
        Toast.makeText(activity, children,
            Toast.LENGTH_SHORT).show();
      }
    });
    return convertView;
  }

  @Override
  public int getChildrenCount(int groupPosition) {
    return groups.get(groupPosition).children.size();
  }

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

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

  @Override
  public void onGroupCollapsed(int groupPosition) {
    super.onGroupCollapsed(groupPosition);
  }

  @Override
  public void onGroupExpanded(int groupPosition) {
    super.onGroupExpanded(groupPosition);
  }

  @Override
  public long getGroupId(int groupPosition) {
    return 0;
  }

  @Override
  public View getGroupView(int groupPosition, boolean isExpanded,
      View convertView, ViewGroup parent) {
    if (convertView == null) {
      convertView = inflater.inflate(R.layout.listrow_group, null);
    }
    Group group = (Group) getGroup(groupPosition);
    ((CheckedTextView) convertView).setText(group.string);
    ((CheckedTextView) convertView).setChecked(isExpanded);
    return convertView;
  }

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

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

Answer 1

這種方法對我也不起作用（我不確定為什么。我的猜測是它僅適用於Contnet提供程序）。 代替使用notifyDataSetChanged()您可以僅向groups重新查詢/添加新數據並重置adapter 。

adapter = new MyExpandableListAdapter(getActivity(), groups);
listView.setAdapter(adapter);

Answer 2

您的if語句可能永遠不會被調用：

 if (termSelection.toString() == "Fall 2013")

應該

 if (termSelection.toString().equals("Fall 2013"))

編輯：

==使用字符串時檢查對象身份。 您很可能是說等於。

另外，我建議您熟悉調試器和/或LogCat / Log.d（），這將為您省去很多麻煩；

Answer 3

您可以再次嘗試設置列表適配器：

listView.setAdapter(adapter);

Answer 4

嘗試用runOnUIThread（new Runnable（...））來包圍您的notifysetchange。 由於您使用listView進行了更改，因此應該在您的UI線程中進行更新。 如果您不熟悉斷點，這也是一個好方法，請嘗試使用if語句記錄日志，並查看您的條件是否設置為true。