java - 在获取预报之前更新位置

Question

我正在制作一个天气应用程序，我当前的问题是天气是根据位置的默认值更新的，而不是等待方法 getLocation() 更新位置。我一刷新，一切正常，但这不是我希望在我的应用程序中发生的情况。这是我的 MainActivity.java: 请原谅我的困惑。它是从一个接一个的代码 fragment 编译而成的，需要进行一些重新组织。

package com.nrsmac.stormy.ui;

import android.content.Context;
import android.content.Intent;
import android.location.Address;
import android.location.Geocoder;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.util.Log;
import android.view.View;
import android.widget.ImageView;
import android.widget.ProgressBar;
import android.widget.RelativeLayout;
import android.widget.TextView;
import android.widget.Toast;

import com.nrsmac.stormy.R;
import com.nrsmac.stormy.weather.Current;
import com.nrsmac.stormy.weather.Day;
import com.nrsmac.stormy.weather.Forecast;
import com.nrsmac.stormy.weather.Hour;
import com.squareup.okhttp.Call;
import com.squareup.okhttp.Callback;
import com.squareup.okhttp.OkHttpClient;
import com.squareup.okhttp.Request;
import com.squareup.okhttp.Response;

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

import java.io.IOException;
import java.util.List;
import java.util.Locale;

import butterknife.ButterKnife;
import butterknife.InjectView;
import butterknife.OnClick;


public class MainActivity extends ActionBarActivity {

    public static final String TAG = MainActivity.class.getSimpleName();

    public static final String DAILY_FORECAST = "DAILY_FORECAST";
    public static final String HOURLY_FORECAST = "HOURLY_FORECAST";

    //9.927128 -84.082012 San José, Costa Rica
    private double mLatitude = 0;
    private double mLongitude = 0;

    public static String cityName = null;
    public static int backgroundColor;

    private Forecast mForecast;

    @InjectView(R.id.relativeLayout)
    RelativeLayout mRelativeLayout;
    @InjectView(R.id.timeLabel)
    TextView mTimeLabel;
    @InjectView(R.id.temperatureLabel)
    TextView mTemperatureLabel;
    @InjectView(R.id.humidityValue)
    TextView mHumidityValue;
    @InjectView(R.id.precipValue)
    TextView mPrecipValue;
    @InjectView(R.id.summaryLabel)
    TextView mSummaryLabel;
    //@InjectView(R.id.iconImageView) ImageView mIconImageView;
    @InjectView(R.id.refreshImageView)
    ImageView mRefreshImageView;
    @InjectView(R.id.progressBar)
    ProgressBar mProgressBar;
    @InjectView(R.id.locationLabel)
    TextView mLocationLabel;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ButterKnife.inject(this);

        mProgressBar.setVisibility(View.INVISIBLE);

        getLocation();

        mRefreshImageView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                getForecast(mLatitude, mLongitude);
            }
        });

        getForecast(mLatitude, mLongitude);

        Log.d(TAG, "Main UI code is running!");
    }

    public void getLocation() {
        LocationManager lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
        LocationListener ll = new LocationListener() {
            @Override
            public void onLocationChanged(Location location) {
                if (location != null){
                    double pLong = location.getLongitude();
                    double pLat = location.getLatitude();

                    mLongitude = pLong;
                    mLatitude = pLat;
                }


                String longitude = "Longitude: " + location.getLongitude();
                Log.v(TAG, longitude);
                String latitude = "Latitude: " + location.getLatitude();
                Log.v(TAG, latitude);
            /*----------to get City-Name from coordinates ------------- */
                Geocoder gcd = new Geocoder(getBaseContext(), Locale.getDefault());
                List<Address> addresses;
                try {
                    addresses = gcd.getFromLocation(location.getLatitude(),
                            location.getLongitude(), 1);
                    if (addresses.size() > 0)
                        System.out.println(addresses.get(0).getLocality());
                    cityName = addresses.get(0).getLocality();
                } catch (IOException e) {
                    e.printStackTrace();
                }

                mLocationLabel.setText(cityName);


            }


            @Override
            public void onStatusChanged(String provider, int status, Bundle extras) {

            }

            @Override
            public void onProviderEnabled(String provider) {

            }

            @Override
            public void onProviderDisabled(String provider) {

            }
        };


//took this to line 123 out to test for gps always on bug, using only line 124 right now
        //exceptions will be thrown if provider is not permitted.
        // try{gps_enabled=lm.isProviderEnabled(LocationManager.GPS_PROVIDER);}catch(Exception ex){}
        //try{network_enabled=lm.isProviderEnabled(LocationManager.NETWORK_PROVIDER);}catch(Exception ex){}


        // if(gps_enabled) {
        // lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 100, 100, ll);
        //if(network_enabled)
        // lm.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 100, 100, ll);

        // }
        lm.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 100, 100, ll);
        // if update broke it, try un-commenting this line, comment out above line?
        //lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 10, 10, ll);

    }





    private void getForecast(double latitude, double longitude) {
        String apiKey = "7a73984cc278e10ed332f1e5d6db96e9";

        String forecastUrl = "https://api.forecast.io/forecast/" + apiKey + "/" + latitude + "," + longitude;

        if (isNetworkAvailable()) {

            toggleRefresh();

            OkHttpClient client = new OkHttpClient();
            Request request = new Request.Builder()
                    .url(forecastUrl)
                    .build();

            Call call = client.newCall(request);
            call.enqueue(new Callback() {
                @Override
                public void onFailure(Request request, IOException e) {
                    runOnUiThread(new Runnable() {
                        @Override
                        public void run() {
                            toggleRefresh();
                        }
                    });
                    alertUserAboutError();
                }

                @Override
                public void onResponse(Response response) throws IOException {
                    runOnUiThread(new Runnable() {
                        @Override
                        public void run() {
                            toggleRefresh();
                        }
                    });

                    try {
                        String jsonData = response.body().string();
                        Log.v(TAG, jsonData);
                        if (response.isSuccessful()) {
                            mForecast = parseForecastDetails(jsonData);
                            runOnUiThread(new Runnable() {
                                @Override
                                public void run() {
                                    updateDisplay();
                                }
                            });

                        } else {
                            alertUserAboutError();
                        }
                    } catch (IOException e) {
                        Log.e(TAG, "Exception caught", e);
                    } catch (JSONException e) {
                        Log.e(TAG, "Exception caught", e);
                    }
                }
            });
        } else {
            Toast.makeText(this, getString(R.string.network_unavailible_message),
                    Toast.LENGTH_LONG).show();
        }
    }

    private void toggleRefresh() {
        getLocation();
        if (mProgressBar.getVisibility() == View.INVISIBLE) {
            mProgressBar.setVisibility(View.VISIBLE);
            mRefreshImageView.setVisibility(View.INVISIBLE);
        }
        else {
            mProgressBar.setVisibility(View.INVISIBLE);
            mRefreshImageView.setVisibility(View.VISIBLE);
        }

    }

    private void updateDisplay() {
        getLocation();
        Current current = mForecast.getCurrent();
        mTemperatureLabel.setText(current.getTemperature() + " degrees");
        mTimeLabel.setText(current.getFormattedTime());
        mHumidityValue.setText(current.getHumidity() + "");
        mPrecipValue.setText(current.getPrecipChance() + "%");
        mSummaryLabel.setText(current.getSummary());

//        Drawable drawable = getResources().getDrawable(current.getIconId());
//        mIconImageView.setImageDrawable(drawable);
        backgroundColor = current.getBackgroundColor();
        mRelativeLayout.setBackgroundColor(backgroundColor);

    }

    private Forecast parseForecastDetails(String jsonData) throws JSONException {
        Forecast forecast = new Forecast();

        forecast.setCurrent(getCurrentDetails(jsonData));
        forecast.setHourlyForecast(getHourlyForecast(jsonData));
        forecast.setDailyForecast(getDailyForecast(jsonData));

        return forecast;
    }

    private Day[] getDailyForecast(String jsonData) throws JSONException {
        JSONObject forecast = new JSONObject(jsonData);
        String timezone = forecast.getString("timezone");
        JSONObject daily = forecast.getJSONObject("daily");
        JSONArray data = daily.getJSONArray("data");

        Day[] days = new Day[data.length()];

        for (int i = 0; i < data.length(); i++) {
            JSONObject jsonDay = data.getJSONObject(i);
            Day day = new Day();

            day.setSummary(jsonDay.getString("summary"));
            day.setIcon(jsonDay.getString("icon"));
            day.setTemperatureMax(jsonDay.getDouble("temperatureMax"));
            day.setTime(jsonDay.getLong("time"));
            day.setTimezone(timezone);

            days[i] = day;
        }

        return days;
    }

    private Hour[] getHourlyForecast(String jsonData) throws JSONException{
        JSONObject forecast = new JSONObject(jsonData);
        String timezone = forecast.getString("timezone");
        JSONObject hourly = forecast.getJSONObject("hourly");
        JSONArray data = hourly.getJSONArray("data");

        Hour[] hours = new Hour[data.length()];

        for (int i = 0; i < data.length(); i++) {
            JSONObject jsonHour = data.getJSONObject(i);
            Hour hour = new Hour();
            hour.setSummary(jsonHour.getString("summary"));
            hour.setTemperature(jsonHour.getDouble("temperature"));
            hour.setIcon(jsonHour.getString("icon"));
            hour.setTime(jsonHour.getLong("time"));
            hour.setTimezone(timezone);

            hours[i] = hour;
        }
        return hours;
    }

    private Current getCurrentDetails(String jsonData) throws JSONException {
        JSONObject forecast = new JSONObject(jsonData);
        String timezone = forecast.getString("timezone");
        Log.i(TAG, "From JSON: " + timezone);

        JSONObject currently = forecast.getJSONObject("currently");

        Current current = new Current();
        current.setHumidity(currently.getDouble("humidity"));
        current.setTime(currently.getLong("time"));
        current.setIcon(currently.getString("icon"));
        current.setPrecipChance(currently.getDouble("precipProbability"));
        current.setSummary(currently.getString("summary"));
        current.setTemperature(currently.getDouble("temperature"));
        current.setTimeZone(timezone);

        Log.d(TAG, current.getFormattedTime());

        return current;
    }

    private boolean isNetworkAvailable() {
        ConnectivityManager manager = (ConnectivityManager)
                getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo networkInfo = manager.getActiveNetworkInfo();
        boolean isAvailible = false;
        if (networkInfo != null && networkInfo.isConnected()) {
            isAvailible = true;
        }

        return isAvailible;
    }

    private void alertUserAboutError() {
        AlertDialogFragment dialog = new AlertDialogFragment();
        dialog.show(getFragmentManager(), "error_dialog");

    }

    @OnClick (R.id.dailyButton)
    public void startDailyActivity(View view) {
        Intent intent = new Intent(this, DailyForecastActivity.class);
        intent.putExtra(DAILY_FORECAST, mForecast.getDailyForecast());
        startActivity(intent);
    }

    @OnClick (R.id.hourlyButton)
    public void startHourlyActivity(View view) {
        Intent intent = new Intent(this, HourlyForecastActivity.class);
        intent.putExtra(HOURLY_FORECAST, mForecast.getHourlyForecast());
        startActivity(intent);
    }

}

Answer 1

我和你的有点一样，我们在同一条船上:)

删除 onCreate 中的 getForecast()。您需要使用 google new FusedLocationApi 更新您的当前位置，因为这避免了 getLastKnowLocation 崩溃。具体使用方法引用here , 并获取代码 here .

然后，您需要在onLocationChanged 方法中handleNewLocation(更新天气)。

和示例代码:

@Override
    public void onLocationChanged(Location location) {
        handleNewLocation(location);
    }

    private void handleNewLocation(Location location) {
        Log.d(TAG, location.toString());

        mLatitude = location.getLatitude();
        mLongitude = location.getLongitude();
        getForecast(mLatitude, mLongitude);
        getCityName();

    }

请记住，在更新天气信息之前，请务必检查 mLongitude != 0 && mLatitude != 0。

如果还是想不明白，请引用我的Github here .