How do I populate an Android spinner using a JSON

问题:

How do I parse a JSON file like the one below containing school names and IDs and use the values in the "Name" field to populate the spinner lables?

I want the spinner to output the selected SchoolID to the next activity. E.g. So you see "Hill View Elementary" and if you select this the value "HVE" is output to the next activity to act on.

{
"schools": [
{
"Name": "Hill View Elementary",
"SchoolID": "HVE"},
{
"Name": "Mill View",
"SchoolID": "MVE"},
{
"Name": "Big School",
"SchoolID": "BSC"},
]
}

Here is the onCreate I'm using to attempt to read the feed...

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);  

    String readFeed = readFeed();
    try {
      JSONArray jsonArray = new
      JSONArray(readFeed);
      Log.i(MainActivity.class.getName(),
          "Number of entries " + jsonArray.length());

      for (int i = 0; i < jsonArray.length(); i++) {
        JSONObject jsonObject = jsonArray.getJSONObject(i);

        // Here instead of Logging I want to use each schools "Name" to 
        // be put into an array that I can use to populate the strings 
        // for the spinner

        Log.i(MainActivity.class.getName(), jsonObject.getString("schools"));

      }
    } catch (Exception e) {
      e.printStackTrace();
    }
}

I'm still coming up to speed on Android so clarity appreciated.

Here is readfeed:

public String readFeed() {
    StringBuilder builder = new StringBuilder();
    HttpClient client = new DefaultHttpClient();

    // domain intentionally obfuscated for security reasons
    HttpGet httpGet = new HttpGet("http://www.domain.com/schools.php");
    try 
 {
      HttpResponse response = client.execute(httpGet);
      StatusLine statusLine = response.getStatusLine();
      int statusCode = statusLine.getStatusCode();
      if (statusCode == 200) {
        HttpEntity entity = response.getEntity();
        InputStream content = entity.getContent();
        BufferedReader reader = new BufferedReader(new InputStreamReader(content));
        String
 line;
        while ((line = reader.readLine()) != null) {
          builder.append(line);
        }
      } else {
        Log.e(MainActivity.class.toString(), "Failed to download file");
      }
    } catch (ClientProtocolException e) {
      e.printStackTrace();
    } catch (IOException e)
 {
      e.printStackTrace();
    }
    return builder.toString();
  }

回答1:

I would do something like this:

public class School {
    private String name;
    private String id;

    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getId() {
        return id;
    }
    public void setId(String id) {
        this.id = id;
    }
}

On create:

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);  

    String readFeed = readFeed();

    // you can use this array to find the school ID based on name
    ArrayList<School> schools = new ArrayList<School>();
    // you can use this array to populate your spinner
    ArrayList<String> schoolNames = new ArrayList<String>();

    try {
      JSONObject json = new JSONObject(readFeed);
      JSONArray jsonArray = new JSONArray(json.optString("schools"));
      Log.i(MainActivity.class.getName(),
          "Number of entries " + jsonArray.length());

      for (int i = 0; i < jsonArray.length(); i++) {
        JSONObject jsonObject = jsonArray.getJSONObject(i);

        School school = new School();
        school.setName(jsonObject.optString("Name"));
        school.setId(jsonObject.optString("SchoolID"));
        schools.add(school);
        schoolNames.add(jsonObject.optString("Name"));

      }
    } catch (Exception e) {
      e.printStackTrace();
    }
    Spinner mySpinner = (Spinner)findViewById(R.id.my_spinner);
    mySpinner.setAdapter(new ArrayAdapter<String>(this, android.R.layout.simple_spinner_dropdown_item, schoolNames));
}

In your main_activity.xml you need a Spinner. The code above would work with a Spinner named like below:

<Spinner
    android:id="@+id/my_spinner"
    android:layout_height="wrap_content"
    android:layout_width="wrap_content"/>