步骤:解析json并存入数据库，

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解析json

package com.example.admin.quakereport.utils;

import android.content.ContentValues;
import android.content.Context;
import android.content.SharedPreferences;
import android.net.Uri;
import android.preference.PreferenceManager;
import android.text.TextUtils;
import android.util.Log;

import com.example.admin.quakereport.R;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.nio.charset.Charset;
import java.text.DecimalFormat;


import com.example.admin.quakereport.data.QuakeContact.QuakeEntry;

public class QueryUtils {

 private static final String LOG_TAG = QueryUtils.class.getSimpleName();

 public static ContentValues[] fetchEarthquakeData(Context context,String requestUrl){
 URL url = createUrl(context,requestUrl);
 String jsonResponse = null;
 try
 { jsonResponse = makehttpRequest(url);
 }catch (IOException e){
 Log.e(LOG_TAG,"Error in making http request",e); }
 ContentValues[] values = extractEarthquakes(context,jsonResponse);
 return values;
 }


 private static URL createUrl(Context context,String mUrl) {
 URL url = null;
 String format="format",getjson="geojson",limit="limit",limit_number="10",minmag="minmag",Orderby="orderby";
 SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(context);
 String minMagnitude = sharedPreferences.getString(context.getString(R.string.settings_min_magnitude_key), context.getString(R.string.settings_min_magnitude_default));
 String orderBy = sharedPreferences.getString(context.getString(R.string.settings_order_by_key), context.getString(R.string.settings_order_by_default));
 Uri uri= Uri.parse(mUrl).buildUpon()
 .appendQueryParameter(format, getjson)
 .appendQueryParameter(limit, limit_number)
 .appendQueryParameter(minmag, minMagnitude)
 .appendQueryParameter(Orderby, orderBy)
 .build();
 try {
 url=new URL(uri.toString());
 } catch (MalformedURLException e) {
 Log.e(LOG_TAG, "Problem building the URL ", e);
 }
 return url;
 }

 private static String makehttpRequest(URL url)throws IOException {
 String jsonResponse = "";
 if (url == null) {
 return jsonResponse;
 }

 HttpURLConnection urlConnection = null;
 InputStream inputStream = null;

 try {
 urlConnection = (HttpURLConnection) url.openConnection();
 urlConnection.setReadTimeout(10000);
 urlConnection.setConnectTimeout(15000);
 urlConnection.setRequestMethod("GET");
 urlConnection.connect();

 if (urlConnection.getResponseCode() == 200) {
 inputStream = urlConnection.getInputStream();
 jsonResponse = readFromStream(inputStream);
 } else {
 Log.e(LOG_TAG, "Error in connection!! Bad Response ");
 }

 } catch (IOException e) {
 Log.e(LOG_TAG, "Problem retrieving the earthquake JSON results.", e);
 } finally {
 {
 if (urlConnection != null) {
 urlConnection.disconnect();
 }
 if (inputStream != null) {
 inputStream.close();
 }
 }
 }
 return jsonResponse;
 }

 private static String readFromStream(InputStream inputStream)throws IOException{
 StringBuilder output = new StringBuilder();
 if (inputStream != null) {
 InputStreamReader inputStreamReader = new InputStreamReader(inputStream, Charset.forName("UTF-8"));
 BufferedReader reader = new BufferedReader(inputStreamReader);
 String line = reader.readLine();

 while (line != null) {
 output.append(line);
 line = reader.readLine();
 }
 }

 return output.toString();
}


 private static ContentValues[] extractEarthquakes(Context context,String earthquakeJSON){
 final String getJsonArray="features",jsObject="properties",double_magnituede="mag",String_location="place"
 ,String_time="time",String_url="url";
 ContentValues[] quakeContentValues=null;

 if (TextUtils.isEmpty(earthquakeJSON)) {
 return null;
 }

 try {
 JSONObject baseJsonResponse = new JSONObject(earthquakeJSON);
 JSONArray featureArray = baseJsonResponse.getJSONArray(getJsonArray);
 quakeContentValues=new ContentValues[featureArray.length()];
 for (int i = 0; i < featureArray.length(); i++) {
 JSONObject currentEarthquake = featureArray.getJSONObject(i);
 JSONObject properties = currentEarthquake.getJSONObject(jsObject);

 double magnitude = properties.getDouble(double_magnituede);
 DecimalFormat magnitudeFormat = new DecimalFormat("0.0");
 String formattedMagnitude=magnitudeFormat.format(magnitude);
 String location = properties.getString(String_location);

 long time = properties.getLong(String_time);
 String url = properties.getString(String_url);
 ContentValues quakeValues=new ContentValues();
 quakeValues.put(QuakeEntry. COLUMN_MAGNITUDE,formattedMagnitude);
 quakeValues.put(QuakeEntry.COLUMN_LOCATION,location);
 quakeValues.put(QuakeEntry.COLUMN_TIME,time);
 quakeValues.put(QuakeEntry.COLUMN_URL,url);
 quakeContentValues[i]=quakeValues;
 }

 }catch (JSONException e){
 Log.e(LOG_TAG,"Error in fetching data",e);
 }
 return quakeContentValues;
 }

}


存入数据库
package com.example.admin.quakereport.sync;

import android.content.ContentResolver;
import android.content.ContentValues;
import android.content.Context;
import android.content.SharedPreferences;
import android.preference.PreferenceManager;
import android.text.format.DateUtils;

import com.example.admin.quakereport.R;
import com.example.admin.quakereport.data.QuakeContact;
import com.example.admin.quakereport.utils.NotificationUtils;
import com.example.admin.quakereport.utils.QueryUtils;

public class QuakeSyncTask {

 private static final String USGS_REQUEST_URL = "https://earthquake.usgs.gov/fdsnws/event/1/query";
 synchronized public static void syncQuake(Context context){
 ContentValues[] values=QueryUtils.fetchEarthquakeData(context,USGS_REQUEST_URL);
 if (values!=null&&values.length!=0){
 ContentResolver resolver=context.getContentResolver();
 resolver.delete(QuakeContact.QuakeEntry.CONTENT_URI,null,null);
 resolver.bulkInsert(QuakeContact.QuakeEntry.CONTENT_URI,values);
 }

 SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(context);
 if (sharedPreferences.getBoolean(context.getString(R.string.settings_notifications_key), true)) {
 long timeSinceLastNotification=getEllapsedTimeSinceLastNotification(context);
 boolean oneDayPassedSinceLastNotification = false;
 if (timeSinceLastNotification >=DateUtils.DAY_IN_MILLIS) {
 oneDayPassedSinceLastNotification = true;
 if (oneDayPassedSinceLastNotification){
 NotificationUtils.notifyUserOfNewQuake(context);
 }
 }
 }

 }

 private static long getEllapsedTimeSinceLastNotification(Context context) {
 long lastNotificationTimeMillis = getLastNotificationTimeInMillis(context);
 long timeSinceLastNotification = System.currentTimeMillis() - lastNotificationTimeMillis;
 return timeSinceLastNotification;
 }

 private static long getLastNotificationTimeInMillis(Context context) {
 String lastNotificationKey = context.getString(R.string.pref_last_notification);
 SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(context);
 long lastNotificationTime = sp.getLong(lastNotificationKey, 0);
 return lastNotificationTime;
 }
}


定时刷新

package com.example.admin.quakereport.sync;

import android.app.AlarmManager;
import android.app.IntentService;
import android.app.PendingIntent;
import android.content.Context;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.SystemClock;


public class AlramIntentService extends IntentService {

 public AlramIntentService() {
 super("AlramIntentService");
 }

 
 @Override
 protected void onHandleIntent(Intent intent) {
 new AsyncTask<Void, Void, Void>() {
 @Override
 protected Void doInBackground(Void... voids) {
 QuakeSyncTask.syncQuake(AlramIntentService.this);
 return null;
 }
 }.execute() ;

 AlarmManager alarmManager=(AlarmManager)getSystemService(Context.ALARM_SERVICE);
 long triggerAtTime=SystemClock.elapsedRealtime()+3*60*60*1000;
 Intent i=new Intent(this,AlarmReceiver.class);
 PendingIntent pendingIntent=PendingIntent.getBroadcast(this,0,i,0);
 alarmManager.setExact(AlarmManager.ELAPSED_REALTIME_WAKEUP,triggerAtTime,pendingIntent);

 }
}



package com.example.admin.quakereport.sync;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;


public class AlarmReceiver extends BroadcastReceiver {
 @Override
 public void onReceive(Context context, Intent intent) {
 intent=new Intent(context,AlramIntentService.class);
 context.startService(intent);
 }
}

Github项目源码：https://github.com/NeoWu55/Android-QuakeReport.git 分支:Backgroud_task

 
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