这是我的代码。
mainactivity.java
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_callplan);
// lv = getListView();
city = (Spinner) findViewById(R.id.city_spinner);
peopleList = new ArrayList<HashMap<String, String>>();
cityList = new ArrayList<City>();
city.setOnItemSelectedListener(this);
new GetCity().execute();
}
private void populateSpinner() {
// txtCategory.setText("");
for (int i = 0; i < cityList.size(); i++) {
cities.add(cityList.get(i).getName());
}
// Creating adapter for spinner
ArrayAdapter<String> spinnerAdapter = new ArrayAdapter<String>(this,
android.R.layout.simple_spinner_item, cities);
// Drop down layout style - list view with radio button
spinnerAdapter
.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
// attaching data adapter to spinner
city.setAdapter(spinnerAdapter);
}
public void onItemSelected(AdapterView<?> parent, View view, int position,
long id) {
// TODO Auto-generated method stub
// new GetCategories().execute();
Spinner city1 = (Spinner) parent;
if (city1.getId() == R.id.city_spinner) {
cityselected = cities.get(position);
Toast.makeText(getApplicationContext(), cityselected,
Toast.LENGTH_LONG).show();
new GetDoctorsDetails().execute();
} else {
Toast.makeText(getApplicationContext(),
"Please Select City from Dropdown Box", Toast.LENGTH_LONG)
.show();
}
}
Asynctask从数据库获取微调数据..
private class GetCity extends AsyncTask<Void, Void, Void> {
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(CallplanActivity.this);
pDialog.setMessage("Fetching cities..");
pDialog.setCancelable(false);
pDialog.show();
}
@Override
protected Void doInBackground(Void... arg0) {
ServiceHandler jsonParser = new ServiceHandler();
String json = jsonParser.makeServiceCall(URL_CITY,
ServiceHandler.GET);
Log.e("Response: ", "> " + json);
if (json != null) {
try {
JSONObject jsonObj = new JSONObject(json);
if (jsonObj != null) {
JSONArray categories = jsonObj
.getJSONArray("doctors_details");
for (int i = 0; i < categories.length(); i++) {
JSONObject catObj = (JSONObject) categories.get(i);
City cat = new City(catObj.getString("city"));
cityList.add(cat);
}
}
} catch (JSONException e) {
e.printStackTrace();
}
} else {
Log.e("JSON Data", "Didn't receive any data from server!");
}
return null;
}
@Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
if (pDialog.isShowing())
pDialog.dismiss();
populateSpinner();
}
}
这是根据在微调器中选择的值从数据库加载listview项的另一个asynctask。
class GetDoctorsDetails extends AsyncTask<String, String, JSONObject> {
JSONObject jsonObject;
@Override
protected void onPreExecute() {
super.onPreExecute();
}
@Override
protected JSONObject doInBackground(String... params) {
// TODO Auto-generated method stub
String city_name = cityselected.toString();
List<NameValuePair> params1 = new ArrayList<NameValuePair>();
params1.add(new BasicNameValuePair("city", city_name));
jsonObject = jParser.makeHttpRequest(URL_DOCTORS, "POST", params1);
return jsonObject;
}
@Override
protected void onPostExecute(JSONObject json) {
if (json != null) {
try {
doctors_info = json.getJSONArray(TAG_DOCDETAILS);
for (int i = 0; i < doctors_info.length(); i++) {
JSONObject c = doctors_info.getJSONObject(i);
String doc_name = c.getString(TAG_DOC_NAME);
String qualification = c.getString(TAG_DOC_QUALI);
HashMap<String, String> map = new HashMap<String, String>();
map.put(TAG_DOC_NAME, doc_name);
map.put(TAG_DOC_QUALI, qualification);
peopleList.add(map);
}
} catch (JSONException e) {
e.printStackTrace();
}
runOnUiThread(new Runnable() {
@Override
public void run() {
// TODO Auto-generated method stub
listview = (ListView) findViewById(R.id.listview);
// Pass the results into ListViewAdapter.java
adapter = new ListViewAdapter(CallplanActivity.this,
peopleList);
// Set the adapter to the ListView
listview.setAdapter(adapter);
adapter.notifyDataSetChanged();
listview.notify();
}
});
}
pDialog.dismiss();
}
}
现在正在加载spinner数据并且listview数据也正确加载但问题是当我从spinner中选择不同的值时，将追加listview中的数据而不是更新。两个微调器数据的值都附加在一个列表视图中。我想在微调器值上显示每个选择的不同数据。
提前感谢。
答案 0 :(得分：0)
在onPostExecute()异步任务的GetDoctorsDetails方法中，在将新结果添加到其中之前，您永远不会清除peopleList数组。整个onPostExecute()方法也在UI线程上执行，因此不需要runOnUiThread。
我要做的是先将listview = (ListView) findViewById(R.id.listview);移至onCreate()方法，以避免在每个微调器更改时都搜索它。
您没有使用peopleList本地数组，为什么不直接将项目添加到适配器？因此，使用onPostExecute()启动adapter.clear()。然后使用adapter.add()将所有项目直接添加到适配器（注意 - 根据您实施适配器的方式，您可能需要对add()进行一些小的更改）。最后，只需执行adapter.notifyDataSetChanged()一次即可完成。
同样不需要额外的peopleList代码也会更具可读性。
答案 1 :(得分：0)
这就是我为解决问题而做的事情
public void onItemSelected(AdapterView<?> parent, View view, int position,
long id) {
// TODO Auto-generated method stub
// new GetCategories().execute();
Spinner city1 = (Spinner) parent;
if (city1.getId() == R.id.city_spinner) {
cityselected = cities.get(position);
Toast.makeText(getApplicationContext(), cityselected,
Toast.LENGTH_LONG).show();
listview = (ListView) findViewById(R.id.listview);
// Pass the results into ListViewAdapter.java
adapter = new ListViewAdapter(CallplanActivity.this, peopleList);
// Set the adapter to the ListView
listview.setAdapter(adapter);
adapter.data.clear();
adapter.notifyDataSetChanged();
new GetDoctorsDetails().execute();
} else {
Toast.makeText(getApplicationContext(),
"Please Select City from Dropdown Box", Toast.LENGTH_LONG)
.show();
}
}