java 阳光网络2

Posted 2021-05-08

package com.example.android.sunshine.utilities;

import android.content.ContentValues;
import android.content.Context;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import java.net.HttpURLConnection;

/**
 * Utility functions to handle OpenWeatherMap JSON data.
 */
public final class OpenWeatherJsonUtils {

    /**
     * This method parses JSON from a web response and returns an array of Strings
     * describing the weather over various days from the forecast.
     * <p/>
     * Later on, we'll be parsing the JSON into structured data within the
     * getFullWeatherDataFromJson function, leveraging the data we have stored in the JSON. For
     * now, we just convert the JSON into human-readable strings.
     *
     * @param forecastJsonStr JSON response from server
     *
     * @return Array of Strings describing weather data
     *
     * @throws JSONException If JSON data cannot be properly parsed
     */
    public static String[] getSimpleWeatherStringsFromJson(Context context, String forecastJsonStr)
            throws JSONException {

        /* Weather information. Each day's forecast info is an element of the "list" array */
        final String OWM_LIST = "list";

        /* All temperatures are children of the "temp" object */
        final String OWM_TEMPERATURE = "temp";

        /* Max temperature for the day */
        final String OWM_MAX = "max";
        final String OWM_MIN = "min";

        final String OWM_WEATHER = "weather";
        final String OWM_DESCRIPTION = "main";

        final String OWM_MESSAGE_CODE = "cod";

        /* String array to hold each day's weather String */
        String[] parsedWeatherData = null;

        JSONObject forecastJson = new JSONObject(forecastJsonStr);

        /* Is there an error? */
        if (forecastJson.has(OWM_MESSAGE_CODE)) {
            int errorCode = forecastJson.getInt(OWM_MESSAGE_CODE);

            switch (errorCode) {
                case HttpURLConnection.HTTP_OK:
                    break;
                case HttpURLConnection.HTTP_NOT_FOUND:
                    /* Location invalid */
                    return null;
                default:
                    /* Server probably down */
                    return null;
            }
        }

        JSONArray weatherArray = forecastJson.getJSONArray(OWM_LIST);

        parsedWeatherData = new String[weatherArray.length()];

        long localDate = System.currentTimeMillis();
        long utcDate = SunshineDateUtils.getUTCDateFromLocal(localDate);
        long startDay = SunshineDateUtils.normalizeDate(utcDate);

        for (int i = 0; i < weatherArray.length(); i++) {
            String date;
            String highAndLow;

            /* These are the values that will be collected */
            long dateTimeMillis;
            double high;
            double low;
            String description;

            /* Get the JSON object representing the day */
            JSONObject dayForecast = weatherArray.getJSONObject(i);

            /*
             * We ignore all the datetime values embedded in the JSON and assume that
             * the values are returned in-order by day (which is not guaranteed to be correct).
             */
            dateTimeMillis = startDay + SunshineDateUtils.DAY_IN_MILLIS * i;
            date = SunshineDateUtils.getFriendlyDateString(context, dateTimeMillis, false);

            /*
             * Description is in a child array called "weather", which is 1 element long.
             * That element also contains a weather code.
             */
            JSONObject weatherObject =
                    dayForecast.getJSONArray(OWM_WEATHER).getJSONObject(0);
            description = weatherObject.getString(OWM_DESCRIPTION);

            /*
             * Temperatures are sent by Open Weather Map in a child object called "temp".
             *
             * Editor's Note: Try not to name variables "temp" when working with temperature.
             * It confuses everybody. Temp could easily mean any number of things, including
             * temperature, temporary and is just a bad variable name.
             */
            JSONObject temperatureObject = dayForecast.getJSONObject(OWM_TEMPERATURE);
            high = temperatureObject.getDouble(OWM_MAX);
            low = temperatureObject.getDouble(OWM_MIN);
            highAndLow = SunshineWeatherUtils.formatHighLows(context, high, low);

            parsedWeatherData[i] = date + " - " + description + " - " + highAndLow;
        }

        return parsedWeatherData;
    }

    /**
     * Parse the JSON and convert it into ContentValues that can be inserted into our database.
     *
     * @param context         An application context, such as a service or activity context.
     * @param forecastJsonStr The JSON to parse into ContentValues.
     *
     * @return An array of ContentValues parsed from the JSON.
     */
    public static ContentValues[] getFullWeatherDataFromJson(Context context, String forecastJsonStr) {
        /** This will be implemented in a future lesson **/
        return null;
    }
}

package com.example.android.sunshine.utilities;

import android.net.Uri;
import android.util.Log;

import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Scanner;

/**
 * These utilities will be used to communicate with the weather servers.
 */
public final class NetworkUtils {

    private static final String TAG = NetworkUtils.class.getSimpleName();

    private static final String DYNAMIC_WEATHER_URL =
            "https://andfun-weather.udacity.com/weather";

    private static final String STATIC_WEATHER_URL =
            "https://andfun-weather.udacity.com/staticweather";

    private static final String FORECAST_BASE_URL = STATIC_WEATHER_URL;

    /*
     * NOTE: These values only effect responses from OpenWeatherMap, NOT from the fake weather
     * server. They are simply here to allow us to teach you how to build a URL if you were to use
     * a real API.If you want to connect your app to OpenWeatherMap's API, feel free to! However,
     * we are not going to show you how to do so in this course.
     */

    /* The format we want our API to return */
    private static final String format = "json";
    /* The units we want our API to return */
    private static final String units = "metric";
    /* The number of days we want our API to return */
    private static final int numDays = 14;

    final static String QUERY_PARAM = "q";
    final static String LAT_PARAM = "lat";
    final static String LON_PARAM = "lon";
    final static String FORMAT_PARAM = "mode";
    final static String UNITS_PARAM = "units";
    final static String DAYS_PARAM = "cnt";

    /**
     * Builds the URL used to talk to the weather server using a location. This location is based
     * on the query capabilities of the weather provider that we are using.
     *
     * @param locationQuery The location that will be queried for.
     * @return The URL to use to query the weather server.
     */
    public static URL buildUrl(String locationQuery) {
        // COMPLETED (1) Fix this method to return the URL used to query Open Weather Map's API
        Uri builtUri = Uri.parse(FORECAST_BASE_URL).buildUpon()
                .appendQueryParameter(QUERY_PARAM, locationQuery)
                .appendQueryParameter(FORMAT_PARAM, format)
                .appendQueryParameter(UNITS_PARAM, units)
                .appendQueryParameter(DAYS_PARAM, Integer.toString(numDays))
                .build();

        URL url = null;
        try {
            url = new URL(builtUri.toString());
        } catch (MalformedURLException e) {
            e.printStackTrace();
        }

        Log.v(TAG, "Built URI " + url);

        return url;
    }

    /**
     * Builds the URL used to talk to the weather server using latitude and longitude of a
     * location.
     *
     * @param lat The latitude of the location
     * @param lon The longitude of the location
     * @return The Url to use to query the weather server.
     */
    public static URL buildUrl(Double lat, Double lon) {
        /** This will be implemented in a future lesson **/
        return null;
    }

    /**
     * This method returns the entire result from the HTTP response.
     *
     * @param url The URL to fetch the HTTP response from.
     * @return The contents of the HTTP response.
     * @throws IOException Related to network and stream reading
     */
    public static String getResponseFromHttpUrl(URL url) throws IOException {
        HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
        try {
            InputStream in = urlConnection.getInputStream();

            Scanner scanner = new Scanner(in);
            scanner.useDelimiter("\\A");

            boolean hasInput = scanner.hasNext();
            if (hasInput) {
                return scanner.next();
            } else {
                return null;
            }
        } finally {
            urlConnection.disconnect();
        }
    }
}

package com.example.android.sunshine;

import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.widget.TextView;

import com.example.android.sunshine.data.SunshinePreferences;
import com.example.android.sunshine.utilities.NetworkUtils;
import com.example.android.sunshine.utilities.OpenWeatherJsonUtils;

import java.net.URL;

public class MainActivity extends AppCompatActivity {

    private TextView mWeatherTextView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_forecast);

        /*
         * Using findViewById, we get a reference to our TextView from xml. This allows us to
         * do things like set the text of the TextView.
         */
        mWeatherTextView = (TextView) findViewById(R.id.tv_weather_data);

        /* Once all of our views are setup, we can load the weather data. */
        loadWeatherData();
    }

    // COMPLETED (8) Create a method that will get the user's preferred location and execute your new AsyncTask and call it loadWeatherData
    /**
     * This method will get the user's preferred location for weather, and then tell some
     * background method to get the weather data in the background.
     */
    private void loadWeatherData() {
        String location = SunshinePreferences.getPreferredWeatherLocation(this);
        new FetchWeatherTask().execute(location);
    }

    public class FetchWeatherTask extends AsyncTask<String, Void, String[]> {
      
        @Override
        protected String[] doInBackground(String... params) {

            /* If there's no zip code, there's nothing to look up. */
            if (params.length == 0) {
                return null;
            }

            String location = params[0];
            URL weatherRequestUrl = NetworkUtils.buildUrl(location);

            try {
                String jsonWeatherResponse = NetworkUtils
                        .getResponseFromHttpUrl(weatherRequestUrl);

                String[] simpleJsonWeatherData = OpenWeatherJsonUtils
                        .getSimpleWeatherStringsFromJson(MainActivity.this, jsonWeatherResponse);

                return simpleJsonWeatherData;

            } catch (Exception e) {
                e.printStackTrace();
                return null;
            }
        }
        
        @Override
        protected void onPostExecute(String[] weatherData) {
            if (weatherData != null) {
                /*
                 * Iterate through the array and append the Strings to the TextView. The reason why we add
                 * the "\n\n\n" after the String is to give visual separation between each String in the
                 * TextView. Later, we'll learn about a better way to display lists of data.
                 */
                for (String weatherString : weatherData) {
                    mWeatherTextView.append((weatherString) + "\n\n\n");
                }
            }
        }
    }
}