如何在微调器中设置初始文本而不是 json 响应的第一项

Question

我在我的应用程序中使用 json 解析，我从 json 获取国家名称，问题出在我的 json 响应中，第一个国家是 "Andorra"，但默认情况下我想显示 "Select Country"，以下是我的 json 响应和代码，有人可以帮助我吗？？

[{"user_status":"1","country_id":"1","country":"Andorra"},{"user_status":"1","country_id":"2","country":"United Arab Emirates"},{"user_status":"1","country_id":"3","country":"Afghanistan"},{"user_status":"1","country_id":"4","country":"Antigua and Barbuda"},{"user_status":"1","country_id":"5","country":"Anguilla"},{"user_status":"1","country_id":"6","country":"Albania"},{"user_status":"1","country_id":"7","country":"Armenia"},{"user_status":"1","country_id":"8","country":"Angola"},]

我的代码

class Logincity extends
            AsyncTask<String, String, ArrayList<HashMap<String, String>>> {
        private ProgressDialog pDialog;
        private String test;

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            pDialog = new ProgressDialog(Registration.this);
            pDialog.setMessage("Please wait..");
            pDialog.setIndeterminate(true);
            pDialog.setIndeterminateDrawable(getResources().getDrawable(R.drawable.custom_progress));
            pDialog.setCancelable(true);
            pDialog.show();
        }
        protected ArrayList<HashMap<String, String>> doInBackground(
                String... args) {
            ServiceHandler sh = new ServiceHandler();
            // Making a request to url and getting response
            citydata = new ArrayList<HashMap<String, String>>();
            String jsonStr = sh.makeServiceCall(CITY_URL, ServiceHandler.GET);
            Log.d("Response: ", "> " + jsonStr);
            if (jsonStr != null) {
                try {
                    jsonObjcitys = new JSONArray(jsonStr);
                    // state_list = jsonObj.getJSONArray(COUNTRY_LIST);
                    // looping through All Contacts
                    for (int i = 0; i < jsonObjcitys.length(); i++) {
                        JSONObject c = jsonObjcitys.getJSONObject(i);
                        // creating new HashMap
                        HashMap<String, String> map = new HashMap<String, String>();
                        // adding each child node to HashMap key => value
                        //map.put(CITY_NAME, c.getString(CITY_NAME));

                        map.put(CITY_NAME, c.getString(CITY_NAME));
                        //  map.put(PRESET_TITLES, c.getString(PRESET_TITLES));
                        citydata.add(map);

                    }
                } catch (JSONException e) {
                    e.printStackTrace();
                }
            } else {
                Log.e("ServiceHandler", "Couldn't get any data from the url");
            }
            return citydata;
        }
        protected void onPostExecute(ArrayList<HashMap<String, String>> result) {
            super.onPostExecute(result);
            pDialog.dismiss();
            arrallcitiies = new String[citydata.size()];
            for (int index = 0; index < citydata.size(); index++) {
                HashMap<String, String> map = citydata.get(index);
                arrallcitiies[index] = map.get(CITY_NAME);
            }
            // pass arrConuntry array to ArrayAdapter<String> constroctor :
            adapterallcities = new ArrayAdapter<String>(
                    Registration.this,
                    android.R.layout.simple_spinner_dropdown_item, arrallcitiies);
            spinrcountry.setAdapter(adapterallcities);

            spinrcountry.setPrompt("Select City");
            spinrcountry.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
                @Override
                public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) {
                    cityspitems = spinrcountry.getSelectedItem().toString();
                    System.out.println("PresetEVent selected" + cityspitems);
                }

                @Override
                public void onNothingSelected(AdapterView<?> adapterView) {
                }
            });




        }
    }

Answer 1

只需要在该数组的第一个位置添加 "Select Country" 和 length=response items + 1

    arrallcitiies = new String[citydata.size()+1];
    arrallcitiies[0]="Select Country"; //item at pos 0
    int j=1;
    for (int index = 0; index < citydata.size(); index++) {
    HashMap<String, String> map = citydata.get(index);
    arrallcitiies[j++] = map.get(CITY_NAME);
    }

    adapterallcities = new ArrayAdapter<String>(Registration.this,
                        android.R.layout.simple_spinner_dropdown_item, arrallcitiies);
    spinrcountry.setAdapter(adapterallcities);

Answer 2

您可以编辑

   // Making a request to url and getting response
            citydata = new ArrayList<HashMap<String, String>>();
            String jsonStr = sh.makeServiceCall(CITY_URL, ServiceHandler.GET);

吼叫：

// Making a request to url and getting response
            citydata = new ArrayList<HashMap<String, String>>();
            HashMap<String, String> map_select_country = new HashMap<String, String>();
            map_select_country.put("0","Select country");
            citydata.add(map_select_country); //add new this
            String jsonStr = sh.makeServiceCall(CITY_URL, ServiceHandler.GET);

Answer 3

尝试使用此代码

ArrayList<String> listcountry_id,listcountry;

listcountry_id=new ArrayList<String>();
listcountry=new ArrayList<String>();

 try {  
        JSONArray jarr=new JSONArray("your responce data here");

        for(int i=0;i<jarr.length();i++){

            JSONObject jobj=jarr.getJSONObject(i);
            listcountry_id.add(jobj.getString("country_id"));
            listcountry.add(jobj.getString("country"));              
        }       
    BindSpinnerData();      
    } catch (JSONException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }       
}

 spnData.setOnItemSelectedListener(new OnItemSelectedListener() {

        @Override
        public void onItemSelected(AdapterView<?> parent, View view,
                int position, long id) {
            // TODO Auto-generated method stub
            String ids = String.valueOf(position);
        }

        @Override
        public void onNothingSelected(AdapterView<?> arg0) {
            // TODO Auto-generated method stub

        }
    });

private void BindSpinnerData() {
    // TODO Auto-generated method stub
    ArrayAdapter<String> spinnerLocation = new ArrayAdapter<String>(
            getApplicationContext(), R.layout.spinneritem, listcountry);
    spinnerLocation.setDropDownViewResource(R.layout.spinnerpopup);
    spnData.setAdapter(spinnerLocation); 
}

//spinneritem,spinnerpopup 是textview布局，可以设置文字颜色和背景颜色

Answer 4

在 doInBackground()

中更改以下内容

HashMap<String, String> map = new HashMap<String, String>();

for (int i = 0; i < jsonObjcitys.length(); i++) {
    JSONObject c = jsonObjcitys.getJSONObject(i);
    // creating new HashMap

    // adding each child node to HashMap key => value
    //map.put(CITY_NAME, c.getString(CITY_NAME));

    map.put(CITY_NAME, c.getString(CITY_NAME));
    //  map.put(PRESET_TITLES, c.getString(PRESET_TITLES));
    citydata.add(map);

}
map.put("Select_City", "Select City");
citydata.add(map);

在 onPostExecute()
中更改以下内容
- 设置微调器适配器后添加下面一行。
```
spinrcountry.setSelection(adapter.getCount());
```

您必须创建自定义适配器

public class HintAdapter extends ArrayAdapter < Objects > {


public HintAdapter(Context theContext, int theLayoutResId, String[] objects) {
    super(theContext, theLayoutResId, R.id.text1, objects);
}

@Override
public int getCount() {
    // don't display last item. It is used as hint.
    int count = super.getCount();
    return count > 0 ? count - 1 : count;
}
}

将 onPostExecute() 中的 setAdapter 行更改为以下-

adapterallcities = new HintAdapter(
            Registration.this,
            android.R.layout.simple_spinner_dropdown_item, arrallcitiies);

以上解决方案将显示默认 "Select City" 值，并且在微调器选择时将仅显示城市名称列表，没有默认值。

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