如何在Android中分别显示openweather地图数据？

Question

I am trying to learn Android Async and json data parsing. I am using openweathermap.org API for displaying current weather for a place user type. My application displayed it However, it is not flexible as it is displaying all different details such as weather description, latitude, longitude, Wind Speed , current temperature.. all in a single string so it is not reusable which we should make. Suppose if i want to display the place on google map with current temperature with a map marker, I should be able to get only what i want in this case current temperature and latitude and longitude. I want these details to display on separate textfields. I am beginner in Android. Please look into my code and suggest me with a solution and guidance.

Here is my JSONWeatherData.java

public class JSONWeatherData {
    public static String getData(String weatherJson) throws JSONException {
        String jsonResult = "";
        try {
            JSONObject JsonObject = new JSONObject(weatherJson);
            String cod = jsonHelperGetString(JsonObject, "cod");
            if(cod != null) {
                if (cod.equals("200")) {
                    jsonResult += jsonHelperGetString(JsonObject, "name") + "\n";
                    JSONObject sys = jsonHelperGetJSONObject(JsonObject, "sys");
                    if (sys != null) {
                        jsonResult += jsonHelperGetString(sys, "country") + "\n";
                    }
                    jsonResult += "\n";
                    JSONObject coord = jsonHelperGetJSONObject(JsonObject, "coord");
                    if(coord != null){
                        String lon = jsonHelperGetString(coord, "lon");
                        String lat = jsonHelperGetString(coord, "lat");
                        jsonResult += "Lon: " + lon + "\n";
                        jsonResult += "Lat: " + lat + "\n";
                    }
                    jsonResult += "\n";
                    JSONArray weather = jsonHelperGetJSONArray(JsonObject, "weather");
                    if(weather != null){
                        for(int i=0; i<weather.length(); i++){
                            JSONObject thisWeather = weather.getJSONObject(i);
                            jsonResult += "Weather " + i + ":\n";
                            jsonResult += jsonHelperGetString(thisWeather, "main") + "\n";
                            jsonResult += jsonHelperGetString(thisWeather, "description") + "\n";
                            jsonResult += "\n";
                        }
                    }
                    JSONObject main = jsonHelperGetJSONObject(JsonObject, "main");
                    if(main != null){
                        jsonResult += "temp: " + jsonHelperGetString(main, "temp") + "\n";
                        jsonResult += "\n";
                    }
                    JSONObject wind = jsonHelperGetJSONObject(JsonObject, "wind");
                    if(wind != null){
                        jsonResult += "Wind Speed: " + jsonHelperGetString(wind, "speed") + "\n";
                        jsonResult += "\n";
                    }
                }
                else if(cod.equals("404")){
                    String message = jsonHelperGetString(JsonObject, "message");
                    jsonResult += "cod 404: " + message;
                }
            } else{
                jsonResult += "cod == null\n";
            }
        } catch (JSONException e) {
            e.printStackTrace();
            Log.e(TAG, e.getMessage(), e);
            jsonResult += e.getMessage();
        }
        return jsonResult;
    }
    private static String jsonHelperGetString(JSONObject obj, String k){
        String v = null;
        try {
            v = obj.getString(k);
        } catch (JSONException e) {
            e.printStackTrace();
        }
        return v;
    }
    private static JSONObject jsonHelperGetJSONObject(JSONObject obj, String k){
        JSONObject o = null;
        try {
            o = obj.getJSONObject(k);
        } catch (JSONException e) {
            e.printStackTrace();
        }
        return o;
    }
    private static JSONArray jsonHelperGetJSONArray(JSONObject obj, String k){
        JSONArray a = null;
        try {
            a = obj.getJSONArray(k);
        } catch (JSONException e) {
            e.printStackTrace();
        }
        return a;
    }
}

Main Activity

Public class MainActivity extends Activity {
    Button btnSubmitCity, btnMap;
    EditText editCityText;
    TextView weather_description, current_temp, wind_speed, textViewResult;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        editCityText = (EditText) findViewById(R.id.editCity);
        btnMap =(Button) findViewById(R.id.mapButton);
        btnSubmitCity = (Button) findViewById(R.id.submitCity);
        weather_description = (TextView) findViewById(R.id.weatherDescription);
        current_temp = (TextView) findViewById(R.id.currentTemp);
        wind_speed = (TextView) findViewById(R.id.windSpeed);
        //textViewResult = (TextView)findViewById(R.id.result);
        textViewResult = (TextView)findViewById(R.id.result);
        btnMap.setVisibility(View.INVISIBLE);
        btnMap.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
            }
        });
        btnSubmitCity.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //editCityText.getText().toString();
                //HttpGetTask
                String cityString = editCityText.getText().toString();
                if(TextUtils.isEmpty(cityString)) {
                    Toast.makeText(MainActivity.this, "Enter a place", Toast.LENGTH_LONG).show();
                    return;
                } else{
                    new HttpGetTask(cityString, weather_description).execute(cityString);
                    btnMap.setVisibility(View.VISIBLE);
                }
                //String cityString = city.getText().toString();
                //new HttpGetTask().execute();
                /*
                  new HttpGetTask(
                        editCityText.getText().toString(),
                        textViewResult).execute();
                 */
            }
        });
    }
    private class HttpGetTask extends AsyncTask<String, Void, String> {
        final String FORECAST_BASE_URL = "http://api.openweathermap.org/data/2.5/weather?";
        private static final String TAG = "HttpGetTask";
        String cityName;
        TextView tvResult;
        HttpGetTask(String cityName, TextView tvResult){
            this.cityName = cityName;
            this.tvResult = tvResult;
        }
        @Override
        protected String doInBackground(String... params){
            InputStream in = null;
            HttpURLConnection httpUrlConnection = null;
            String result = "";
            try {
                Uri builtUri = Uri.parse(FORECAST_BASE_URL).buildUpon()
                        .appendQueryParameter("q", cityName+",us") // city
                        .appendQueryParameter("mode", "json") // json format as result
                        .appendQueryParameter("units", "imperial") // metric unit
                        .appendQueryParameter("APPID", "Replace with your openweathermap API ID")
                        .build();
                URL url = new URL(builtUri.toString());
                httpUrlConnection = (HttpURLConnection) url.openConnection();
                in = new BufferedInputStream(
                        httpUrlConnection.getInputStream());
                String data = readStream(in);
                result = edu.uco.rawal.p6rabina.JSONWeatherData.getData(data);
            } catch (MalformedURLException exception) {
                Log.e(TAG, "MalformedURLException");
            } catch (IOException exception) {
                Log.e(TAG, "IOException");
            } catch (JSONException e) {
                Log.e(TAG, e.getMessage(), e);
                e.printStackTrace();
            } finally {
                if (null != httpUrlConnection) {
                    httpUrlConnection.disconnect();
                }
                if (in != null) {
                    try {
                        in.close();
                    } catch (final IOException e) {
                        Log.e(TAG, "Error closing stream", e);
                    }
                }
        }
            return result;
        }
        @Override
        protected void onPostExecute(String result) {
            if (result == null || result == "") {
                Toast.makeText(MainActivity.this,
                        "Invalid weather data. Possibly a wrong query",
                        Toast.LENGTH_SHORT).show();
                return;
            } else {
                //btnMap.setVisibility(View.VISIBLE);
                tvResult.setText(result);
            }

        }
        private String readStream(InputStream in) {
            BufferedReader reader = null;
            StringBuffer data = new StringBuffer("");
            try {
                reader = new BufferedReader(new InputStreamReader(in));
                String line ;
                while ((line = reader.readLine()) != null) {
                    data.append(line);
                }
            } catch (IOException e) {
                Log.e(TAG, "IOException");
            } finally {
                if (reader != null) {
                    try {
                        reader.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            }
            return data.toString();
        }
    }
}

This code runs and output current weather but its not reusuable because everything is concatenated to single string.

Answer 1

To make it reusable and easy to access to each attribute as you want, how about making a class Weather that contains those attribute and when you start parsing the json, make an instance of it and write them there.

For example, instead of just this:

String lon = jsonHelperGetString(coord, "lon");
String lat = jsonHelperGetString(coord, "lat");
jsonResult += "Lon: " + lon + "\n";
jsonResult += "Lat: " + lat + "\n";
...

change to sth like:

Weather aWeather = new Weather();
String lon = jsonHelperGetString(coord, "lon");
String lat = jsonHelperGetString(coord, "lat");
aWeather.lon = long;
aWeather.lat = lat;
...
return aWeather;

Remember to change return type onPostExcute(String string) into onPostExcute(Weather weather);