我使用
JSON从数据库中获取值并将它们插入到微调器中.此过程已成功运行.
但是当我点击旋转器时,我收到了两次Spinner提示;如何从微调器中删除第一个默认值…
但是当我点击旋转器时,我收到了两次Spinner提示;如何从微调器中删除第一个默认值…
这是快照： – 希望你了解我的问题：
这是我的代码： –
private class GetCategories extends AsyncTask<Void,Void,Void> {
protected void onPreExecute() {
super.onPreExecute();
}
@Override
protected Void doInBackground(Void... arg0) {
ServiceHandler jsonParser = new ServiceHandler();
String json = jsonParser.makeServiceCall(URL_CATEGORIES,ServiceHandler.GET);
if (json != null) {
try {
JSONObject jsonObj = new JSONObject(json);
if (jsonObj != null) {
JSONArray categories = jsonObj
.getJSONArray("categories");
categoriesList.clear();
for (int i = 0; i < categories.length(); i++) {
JSONObject catObj = (JSONObject) categories.get(i);
Category cat = new Category(
catObj.getString("bus_type_id"),catObj.getString("bus_type"));
categoriesList.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);
populateSpinner();
}
}
private void populateSpinner() {
List<String> lables = new ArrayList<String>();
lables.add("Choose Type");
for (int i = 0; i < categoriesList.size(); i++) {
lables.add(categoriesList.get(i).getbus_type());
}
// Creating adapter for spinner
ArrayAdapter<String> spinnerAdapter = new ArrayAdapter<String>(this,android.R.layout.simple_spinner_item,lables);
// Drop down layout style - list view with radio button
spinnerAdapter
.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
// attaching data adapter to spinner
typeSpinner.setAdapter(spinnerAdapter);
typeSpinner.setonItemSelectedListener(typeSelectedListener);
}
private OnItemSelectedListener typeSelectedListener = new OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parent,View view,int position,long id) {
if (typeSpinner.getSelectedItem().toString() == "Choose Type") {
str = "";
typeSpinnercity.getSelectedView();
typeSpinnercity.setEnabled(false);
} else {
ok.setEnabled(true);
str = typeSpinner.getSelectedItem().toString();
typeSpinnercity.getSelectedView();
typeSpinnercity.setEnabled(true);
if (Utils.checkInternet(CutomerOfferActivity.this)) {
new GetCategoriesCity().execute();
}
}
}
@Override
public void onnothingSelected(AdapterView<?> parent) {
}
};
解决方法
使用ArrayAdapter并覆盖方法 – getDropDownView ..
ArrayAdapter<String> spinnerAdapter = new ArrayAdapter<String>(this,lables){
@Override
public View getDropDownView(int position,View convertView,ViewGroup parent) {
View v = null;
if (position == 0) {
TextView tv = new TextView(getContext());
tv.setHeight(0);
tv.setVisibility(View.GONE);
v = tv;
}
else {
v = super.getDropDownView(position,null,parent);
}
parent.setVerticalScrollBarEnabled(false);
return v;
}
};
使用上面提到的代码并删除下拉列表中的默认值.