我一直在研究天气应用程序，我知道它并不完美（我刚刚开始使用android开发），但我不确定如何更新每个创业公司的天气信息。我试图在onCreate（）方法中保留所有内容，但它只是＆＃34;坚持＆＃34;关于我刚开始时使用的位置和条件。
我已经能够使用一个按钮来解决这个问题，该按钮在按下时会获得新的位置和天气状况，但这不是很直观。我想知道如何在应用启动时获得新条件。可能涉及调用onRestart（）？
这是我在应用中唯一的活动：
package com.photonfighterlabs.dropweather;
import android.Manifest;
import android.app.Activity;
import android.content.pm.PackageManager;
import android.graphics.drawable.Drawable;
import android.location.Address;
import android.location.Geocoder;
import android.location.Location;
import android.os.Bundle;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.util.Log;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import com.ftoslab.openweatherretrieverz.CurrentWeatherInfo;
import com.ftoslab.openweatherretrieverz.OpenWeatherRetrieverZ;
import com.ftoslab.openweatherretrieverz.WeatherCallback;
import com.ftoslab.openweatherretrieverz.WeatherUnitConverter;
import com.google.android.gms.location.FusedLocationProviderClient;
import com.google.android.gms.location.LocationServices;
import com.google.android.gms.tasks.OnSuccessListener;
import java.io.IOException;
import java.util.List;
import java.util.Locale;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class WeatherActivity extends Activity {
private double lat;
private double lng;
private String temp;
private String icon;
private TextView tempTextView;
private TextView cityTextView;
private TextView conditionsTextView;
private int LOCATION_PERMISSION_ID = 1001;
CurrentWeatherInfo currentWeatherInfoF;
private String city;
private List<Address> addresses;
private FusedLocationProviderClient mFusedLocationClient;
OpenWeatherRetrieverZ retriever;
ImageView image;
Geocoder geocoder;
@Override
public void onCreate(Bundle bundle) {
super.onCreate(bundle);
setContentView(R.layout.activity_weather);
retriever = new OpenWeatherRetrieverZ(API_KEY); // hidden for obvious reasons, but working
mFusedLocationClient = LocationServices.getFusedLocationProviderClient(this);
geocoder = new Geocoder(this, Locale.getDefault());
tempTextView = (TextView) findViewById(R.id.temp_text_view);
cityTextView = (TextView) findViewById(R.id.city_text_view);
conditionsTextView = (TextView) findViewById(R.id.conditions_text_view);
image = (ImageView) findViewById(R.id.conditions_image);
if (ContextCompat.checkSelfPermission(WeatherActivity.this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(WeatherActivity.this, new String[]{Manifest.permission.ACCESS_FINE_LOCATION}, LOCATION_PERMISSION_ID);
return;
}
mFusedLocationClient.getLastLocation()
.addOnSuccessListener(this, new OnSuccessListener<Location>() {
@Override
public void onSuccess(Location location) {
if (location != null)
lat = location.getLatitude();
lng = location.getLongitude();
try {
addresses = geocoder.getFromLocation(lat, lng, 1);
} catch (IOException e) {
e.printStackTrace();
}
if (!addresses.isEmpty()) {
city = addresses.get(0).getLocality();
cityTextView.setText("Current Weather - " + city);
Log.d("City", city);
}
Log.d("LAT", String.valueOf(lat));
Log.d("LNG", String.valueOf(lng));
}
});
retriever.updateCurrentWeatherInfo(lat, lng, new WeatherCallback() {
@Override
public void onReceiveWeatherInfo(CurrentWeatherInfo currentWeatherInfo) {
currentWeatherInfoF = WeatherUnitConverter.convertToImperial(currentWeatherInfo);
}
@Override
public void onFailure(String error) {
Toast.makeText(WeatherActivity.this, error, Toast.LENGTH_SHORT).show();
}
});
}
public void onRetrieveButtonClick(View view) {
mFusedLocationClient.getLastLocation()
.addOnSuccessListener(this, new OnSuccessListener<Location>() {
@Override
public void onSuccess(Location location) {
if (location != null)
lat = location.getLatitude();
lng = location.getLongitude();
try {
addresses = geocoder.getFromLocation(lat, lng, 1);
} catch (IOException e) {
e.printStackTrace();
}
if (!addresses.isEmpty()) {
city = addresses.get(0).getLocality();
cityTextView.setText("Current Weather - " + city);
Log.d("City", city);
}
Log.d("LAT", String.valueOf(lat));
Log.d("LNG", String.valueOf(lng));
}
});
retriever.updateCurrentWeatherInfo(lat, lng, new WeatherCallback() {
@Override
public void onReceiveWeatherInfo(CurrentWeatherInfo currentWeatherInfo) {
currentWeatherInfoF = WeatherUnitConverter.convertToImperial(currentWeatherInfo);
}
@Override
public void onFailure(String error) {
Toast.makeText(WeatherActivity.this, error, Toast.LENGTH_SHORT).show();
}
});
temp = currentWeatherInfoF.getCurrentTemperature();
Log.d("TMP : ", String.valueOf(temp));
tempTextView.setText( String.valueOf((int) Double.parseDouble(temp)) + (char) 0x00B0);
conditionsTextView.setText(currentWeatherInfoF.getWeatherDescriptionLong());
String iconURL = currentWeatherInfoF.getWeatherIconLink().toString();
Pattern p = Pattern.compile("\\d\\w(n|d)");
Matcher m = p.matcher(iconURL);
if (m.find()) {
icon = m.group();
Log.d("ICON", icon);
String iconName = "r" + icon;
image.setImageResource(getResources().getIdentifier(iconName, "drawable", getPackageName()));
Log.d("NAME", iconName);
}
}
}
答案 0 :(得分：1)
getLastLocation()和updateCurrentWeatherInfo(...)都是异步操作。您可以同时启动它们，这意味着updateCurrentWeatherInfo很可能在该位置可用之前运行。
您必须在获得职位后才能启动它，例如来自onSuccess听众。
答案 1 :(得分：0)
你试过onResume（）方法吗？
您可以使用它，当视图可见时
答案 2 :(得分：0)
Awareness提供了snapshot-API，用于在设备位置通过getWeather() API方法获取天气，而无需管理位置访问权限或与从服务器点播查询天气的API集成。
说明性代码段：
Awareness.SnapshotApi.getWeather(mGoogleApiClient)
.setResultCallback(new ResultCallback<WeatherResult>() {
@Override
public void onResult(@NonNull WeatherResult weatherResult) {
if (!weatherResult.getStatus().isSuccess()) {
Log.e(TAG, "Could not get weather.");
return;
}
Weather weather = weatherResult.getWeather();
Log.i(TAG, "Weather: " + weather);
}
});
请参阅here以获取API返回其实例的Weather类的说明。
使用它的好处是，您可以大规模简化代码，避免必须管理位置请求并根据需要经常调用API（我相信它有一个缓存，以避免太多的电池耗尽的网络请求）。