适配器的内容发生了变化，但ListView没有收到通知。（Android错误）

Question

这是我正在尝试做的代码的一部分，请任何人帮助我，我是 android 开发的新手

这是我得到的确切错误： java.lang.IllegalStateException：适配器的内容已更改，但 ListView 没有收到通知。确保适配器的内容不是从后台线程修改的，而只是从 UI 线程修改的。确保您的适配器在其内容更改时调用 notifyDataSetChanged()。 [在 ListView(2131165289, class android.widget.ListView) with Adapter(class android.widget.ArrayAdapter)]

ListView requestListView;

ArrayList<String> requests = new ArrayList<String>();

ArrayAdapter arrayAdapter;

LocationManager locationManager;

LocationListener locationListener;

ArrayList<Double> requestLatitude = new ArrayList<Double>();

ArrayList<Double> requestLongitude = new ArrayList<Double>();

ArrayList<String> UserNames = new ArrayList<String>();

Button refresh;

public void updateListView(Location location){

    if(location!=null) {

        requests.clear();

        ParseQuery<ParseObject> query = new ParseQuery<ParseObject>("Request");

        final ParseGeoPoint geoPointLocation = new ParseGeoPoint(location.getLatitude(), location.getLongitude());

        query.whereNear("location",geoPointLocation);

        query.whereDoesNotExist("driverUserName");

        query.setLimit(10);

        query.findInBackground(new FindCallback<ParseObject>() {
            @Override
            public void done(List<ParseObject> objects, ParseException e) {

                if(e==null){
                    if(objects.size()>0){

                        requests.clear();

                        requestLongitude.clear();

                        requestLatitude.clear();

                        for (ParseObject object:objects){

                            ParseGeoPoint requestLocation = (ParseGeoPoint) object.get("location");

                            if(requestLocation!=null) {

                                Double distanceinMiles = geoPointLocation.distanceInKilometersTo(requestLocation);

                                Double DistanceOneDP = (double) Math.round(distanceinMiles * 10) / 10;

                                requests.add(DistanceOneDP.toString() + "Km");

                                arrayAdapter.notifyDataSetChanged();

                                requestLatitude.add(requestLocation.getLatitude());

                                requestLongitude.add(requestLocation.getLongitude());

                                UserNames.add(object.getString("username"));


                            }
                        }
                    }else{

                        requests.clear();

                        requests.add("No Near By request");
                    }

                    arrayAdapter.notifyDataSetChanged();

                }
            }
        });
    }

}

Answer 1

将适配器设置为 Listview

requestListView.setAdapter(arrayAdapter); 那么

arrayAdapter.notifyDataSetChanged();

Answer 2

先试试这个方法set adapter进入listview。

requestListView.setAdapter(adapter);

之后调用 arrayAdapter.notifyDataSetChanged();