我知道有很多问题询问关于刷新列表时返回最后滚动的位置。但是我不知道为什么在我的情况下（适配器）给定的答案不起作用。我有一个适配器，在给定时间它会刷新新信息并将其加载到适配器中。我想要的是，当它刷新时不要再回到适配器的顶部并保存以前的状态。这是我使用的代码。
创建时
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.all_candidatos);
if (Titulacion.IsReachable1(getApplicationContext())){
new CargarCandidatos().execute();
timer();
}else{
Toast.makeText(getApplicationContext(), R.string.errorserver, Toast.LENGTH_LONG).show();
}
setListAdapter(adapter);
candidatosList = new ArrayList<HashMap<String, String>>();
asynctask 分为两部分。检索信息并将数据适配到适配器中。这是适应它的代码：
protected void onPostExecute(String file_url) {
runOnUiThread(new Runnable() {
public void run() {
adapter = new SimpleAdapter(
Monitorizacion.this, candidatosList,
R.layout.list_item, new String[] { TAG_ID,TAG_NSERIE,TAG_TABLET,
TAG_DNI, TAG_NOMBRE, TAG_TEST, TAG_PREGUNTA, TAG_BATERIA,TAG_CORRECTAS, TAG_ERRORES},
new int[] { R.id.autoid,R.id.id,R.id.tablet, R.id.dni, R.id.nombre, R.id.test, R.id.pregunta, R.id.bateria, R.id.correctas, R.id.fallos});
adapter.notifyDataSetChanged();
setListAdapter(adapter);
}
});
}
但是我应该如何保存适配器的状态，然后考虑之前的状态开始显示项目。
谢谢
编辑：我已经尝试过在返回 ListView 时保持/保存/恢复滚动位置的答案，但我无法使其工作。
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.all_candidatos);
if (Titulacion.IsReachable1(getApplicationContext())){
new CargarCandidatos().execute();
timer();
}else{
Toast.makeText(getApplicationContext(), R.string.errorserver, Toast.LENGTH_LONG).show();
}
setListAdapter(adapter);
candidatosList = new ArrayList<HashMap<String, String>>();
lv = (ListView)findViewById(android.R.id.list);
lv.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
String idd = ((TextView) view.findViewById(R.id.dni)).getText()
.toString();
Intent in = new Intent(getApplicationContext(),
MonitDetail.class);
in.putExtra("idd", idd);
startActivityForResult(in, 100);
}
});
}
//
//
public void timer(){
new CountDownTimer(tiempo, 1000) {
public void onTick(long millisUntilFinished) {
}
public void onFinish() {
index = lv.getFirstVisiblePosition();
v = lv.getChildAt(0);
top = (v == null) ? 0 : v.getTop();
if (Titulacion.IsReachable1(getApplicationContext())){
new CargarCandidatos().execute();
timer();
}else{
Toast.makeText(getApplicationContext(), R.string.errorserver, Toast.LENGTH_LONG).show();
}
}
}.start();}
class CargarCandidatos extends AsyncTask<String, Void, String> {
protected String doInBackground(String... args) {
try {
monitorizar();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();}
return null;
}
protected void onPostExecute(String file_url) {
runOnUiThread(new Runnable() {
public void run() {
adapter = new SimpleAdapter(
Monitorizacion.this, candidatosList,
R.layout.list_item, new String[] { TAG_ID,TAG_NSERIE,TAG_TABLET,
TAG_DNI, TAG_NOMBRE, TAG_TEST, TAG_PREGUNTA, TAG_BATERIA,TAG_CORRECTAS, TAG_ERRORES},
new int[] { R.id.autoid,R.id.id,R.id.tablet, R.id.dni, R.id.nombre, R.id.test, R.id.pregunta, R.id.bateria, R.id.correctas, R.id.fallos});
lv.setSelectionFromTop(index, top);
adapter.notifyDataSetChanged();
lv.setAdapter(adapter);
}
});
}
}
public void monitorizar() throws Exception{
try {
List<NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair("fecha",Titulacion.fecha()));
JSONObject json = jParser.makeHttpRequest(url_candidatos, "GET", params);
ArrayList<HashMap<String, String>> temp;
temp = new ArrayList<HashMap<String, String>>();
int success = json.getInt(TAG_SUCCESS);
if (success == 1) {
candidatos = json.getJSONArray(TAG_CANDIDATOS);
for (int i = 0; i < candidatos.length(); i++) {
JSONObject c = candidatos.getJSONObject(i);
String id = c.getString(TAG_ID);
String nserie = c.getString(TAG_NSERIE);
String tablet = c.getString(TAG_TABLET);
String dni = c.getString(TAG_DNI);
String nombre = c.getString(TAG_NOMBRE);
String test = c.getString(TAG_TEST);
String pregunta = c.getString(TAG_PREGUNTA);
String bateria = c.getString(TAG_BATERIA);
String correctas = c.getString(TAG_CORRECTAS);
String errores = c.getString(TAG_ERRORES);
HashMap<String, String> map = new HashMap<String, String>();
map.put(TAG_ID, id);
map.put(TAG_NSERIE, nserie);
map.put(TAG_TABLET, tablet);
map.put(TAG_DNI, dni);
map.put(TAG_NOMBRE, nombre);
map.put(TAG_TEST, test);
map.put(TAG_PREGUNTA, pregunta);
map.put(TAG_BATERIA, bateria);
map.put(TAG_CORRECTAS, correctas);
map.put(TAG_ERRORES, errores);
temp.add(map);
candidatosList = temp;
}
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}