我正在尝试在 Fragment 中更新 ListView，它实际工作的唯一方法是如果我将片段实例化为新的。adpter.notifyDataSetChanged() 不工作？为什么不呢？这里的代码活动和片段：
public class TimerList extends Activity{
private DataSource datasource;
TimerListFragment timerfragment;
IntervalListFragment intervalfragment;
public List<TimerObject> values;
public String name;
public String intervals;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.interval_fragment_container);
datasource = new DataSource(this);
datasource.open();
values = datasource.getAllComments();
if (savedInstanceState == null) {
Toast.makeText(getApplicationContext(), "MADE NEW FRAGMENTS", Toast.LENGTH_SHORT).show();
timerfragment = new TimerListFragment();
intervalfragment = new IntervalListFragment();
}
}
public void delete(Long position){
TimerObject timerobject = datasource.getTimerObject(position);
datasource.deleteComment(timerobject);
values = datasource.getAllComments();
}
@Override
protected void onStart() {
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.add(R.id.fragment_container, timerfragment);
fragmentTransaction.addToBackStack(null);
fragmentTransaction.commit();
super.onStart();
}
还有我的片段：
public class TimerListFragment extends ListFragment {
List<TimerObject> values ;
Activity a;
ArrayAdapter<TimerObject> adapter;
ListView lv;
@Override
public void onCreate(Bundle savedInstanceState) {
setHasOptionsMenu(true);
values = ((TimerList)getActivity()).getValues();
setBar();
adapter = new ArrayAdapter<TimerObject>(getActivity(), android.R.layout.simple_list_item_1, values);
setListAdapter(adapter);
super.onCreate(savedInstanceState);
}
@Override
public void onListItemClick(ListView l, View v, int position, long id) {
((TimerList)getActivity()).play(Long.valueOf(position));
super.onListItemClick(l, v, position, id);
}
public void setBar(){
ActionBar actionbar = getActivity().getActionBar();
actionbar.setTitle("Timer List");
}
public void update(){
setBar();
Toast.makeText(getActivity(), "UPDATE", Toast.LENGTH_LONG).show();
values = ((TimerList)getActivity()).getValues();
adapter.notifyDataSetChanged();
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.interval_timer_list,
container, false);
return view;
}
@Override
public void onStart() {
update();
lv = getListView();
lv.setOnItemLongClickListener(new OnItemLongClickListener() {
public boolean onItemLongClick(AdapterView parent, View view, int position, long id) {
final TimerObject selected = adapter.getItem(position);
final Dialog d = new Dialog(getActivity());
d.setContentView(R.layout.interval_deletetimer_dialog);
d.setTitle("Delete " + selected.getComment() + "?" );
ImageButton delete = (ImageButton) d.findViewById(R.id.delete);
delete.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
((TimerList)getActivity()).delete(Long.valueOf(selected.getId()));
update();
}
});
d.show();
return true;
}
});
super.onStart();
}