Free eBook Qt 5 Cadaques

Qt 5 Cadaques is a free on-line ebook about Qt5.

The entire collection of chapters covering Qt5 programming, written by Juergen Bocklage-Ryannel and Johan Thelin, is available here. All book content is licensed under the Creative Commons Attribution Non Commercial Share Alike 4.0 license and examples are licensed under the BSD license.

It also provide offline ebook in ePub, PDF and QtHelp format.

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Android query current weather using OpenWeatherMaps Weather API

OpenWeatherMaps weather API is simple, clear and free. This Android example show how access current weather data using OpenWeatherMaps weather API; for any location on Earth including over 200,000 cities! Current weather is frequently updated based on global models and data from more than 40,000 weather stations. Data is available in JSON, XML, or HTML format. This example use JSON.

To access the API you need to sign up for an API key, this example use the demo API Key (appid in the query)

MainActivity.java

package com.blogspot.android_er.androidopenweathermap;

import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

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

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;

public class MainActivity extends AppCompatActivity {

 EditText editTextCityName;
 Button btnByCityName;
 TextView textViewResult, textViewInfo;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main);
 editTextCityName = (EditText)findViewById(R.id.cityname);
 btnByCityName = (Button)findViewById(R.id.bycityname);
 textViewResult = (TextView)findViewById(R.id.result);
 textViewInfo = (TextView)findViewById(R.id.info);

 btnByCityName.setOnClickListener(new View.OnClickListener() {
 @Override
 public void onClick(View v) {
 new OpenWeatherMapTask(
 editTextCityName.getText().toString(),
 textViewResult).execute();
 }
 });
 }

 private class OpenWeatherMapTask extends AsyncTask<Void, Void, String> {

 String cityName;
 TextView tvResult;

 String dummyAppid = "bd82977b86bf27fb59a04b61b657fb6f";
 String queryWeather = "http://api.openweathermap.org/data/2.5/weather?q=";
 String queryDummyKey = "&appid=" + dummyAppid;

 OpenWeatherMapTask(String cityName, TextView tvResult){
 this.cityName = cityName;
 this.tvResult = tvResult;
 }

 @Override
 protected String doInBackground(Void... params) {
 String result = "";
 String queryReturn;

 String query = null;
 try {
 query = queryWeather + URLEncoder.encode(cityName, "UTF-8") + queryDummyKey;
 queryReturn = sendQuery(query);
 result += ParseJSON(queryReturn);
 } catch (UnsupportedEncodingException e) {
 e.printStackTrace();
 queryReturn = e.getMessage();
 } catch (IOException e) {
 e.printStackTrace();
 queryReturn = e.getMessage();
 }


 final String finalQueryReturn = query + " " + queryReturn;
 runOnUiThread(new Runnable() {
 @Override
 public void run() {
 textViewInfo.setText(finalQueryReturn);
 }
 });


 return result;
 }

 @Override
 protected void onPostExecute(String s) {
 tvResult.setText(s);
 }

 private String sendQuery(String query) throws IOException {
 String result = "";

 URL searchURL = new URL(query);

 HttpURLConnection httpURLConnection = (HttpURLConnection)searchURL.openConnection();
 if(httpURLConnection.getResponseCode() == HttpURLConnection.HTTP_OK){
 InputStreamReader inputStreamReader = new InputStreamReader(httpURLConnection.getInputStream());
 BufferedReader bufferedReader = new BufferedReader(
 inputStreamReader,
 8192);

 String line = null;
 while((line = bufferedReader.readLine()) != null){
 result += line;
 }

 bufferedReader.close();
 }

 return result;
 }

 private String ParseJSON(String json){
 String jsonResult = "";

 try {
 JSONObject JsonObject = new JSONObject(json);
 String cod = jsonHelperGetString(JsonObject, "cod");

 if(cod != null){
 if(cod.equals("200")){

 jsonResult += jsonHelperGetString(JsonObject, "name") + " ";
 JSONObject sys = jsonHelperGetJSONObject(JsonObject, "sys");
 if(sys != null){
 jsonResult += jsonHelperGetString(sys, "country") + " ";
 }
 jsonResult += " ";

 JSONObject coord = jsonHelperGetJSONObject(JsonObject, "coord");
 if(coord != null){
 String lon = jsonHelperGetString(coord, "lon");
 String lat = jsonHelperGetString(coord, "lat");
 jsonResult += "lon: " + lon + " ";
 jsonResult += "lat: " + lat + " ";
 }
 jsonResult += " ";

 JSONArray weather = jsonHelperGetJSONArray(JsonObject, "weather");
 if(weather != null){
 for(int i=0; i<weather.length(); i++){
 JSONObject thisWeather = weather.getJSONObject(i);
 jsonResult += "weather " + i + ": ";
 jsonResult += "id: " + jsonHelperGetString(thisWeather, "id") + " ";
 jsonResult += jsonHelperGetString(thisWeather, "main") + " ";
 jsonResult += jsonHelperGetString(thisWeather, "description") + " ";
 jsonResult += " ";
 }
 }

 JSONObject main = jsonHelperGetJSONObject(JsonObject, "main");
 if(main != null){
 jsonResult += "temp: " + jsonHelperGetString(main, "temp") + " ";
 jsonResult += "pressure: " + jsonHelperGetString(main, "pressure") + " ";
 jsonResult += "humidity: " + jsonHelperGetString(main, "humidity") + " ";
 jsonResult += "temp_min: " + jsonHelperGetString(main, "temp_min") + " ";
 jsonResult += "temp_max: " + jsonHelperGetString(main, "temp_max") + " ";
 jsonResult += "sea_level: " + jsonHelperGetString(main, "sea_level") + " ";
 jsonResult += "grnd_level: " + jsonHelperGetString(main, "grnd_level") + " ";
 jsonResult += " ";
 }

 jsonResult += "visibility: " + jsonHelperGetString(JsonObject, "visibility") + " ";
 jsonResult += " ";

 JSONObject wind = jsonHelperGetJSONObject(JsonObject, "wind");
 if(wind != null){
 jsonResult += "wind: ";
 jsonResult += "speed: " + jsonHelperGetString(wind, "speed") + " ";
 jsonResult += "deg: " + jsonHelperGetString(wind, "deg") + " ";
 jsonResult += " ";
 }

 //...incompleted

 }else if(cod.equals("404")){
 String message = jsonHelperGetString(JsonObject, "message");
 jsonResult += "cod 404: " + message;
 }
 }else{
 jsonResult += "cod == null ";
 }

 } catch (JSONException e) {
 e.printStackTrace();
 jsonResult += e.getMessage();
 }

 return jsonResult;
 }

 private String jsonHelperGetString(JSONObject obj, String k){
 String v = null;
 try {
 v = obj.getString(k);
 } catch (JSONException e) {
 e.printStackTrace();
 }

 return v;
 }

 private JSONObject jsonHelperGetJSONObject(JSONObject obj, String k){
 JSONObject o = null;

 try {
 o = obj.getJSONObject(k);
 } catch (JSONException e) {
 e.printStackTrace();
 }

 return o;
 }

 private JSONArray jsonHelperGetJSONArray(JSONObject obj, String k){
 JSONArray a = null;

 try {
 a = obj.getJSONArray(k);
 } catch (JSONException e) {
 e.printStackTrace();
 }

 return a;
 }
 }
}

layout/activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
 
 
 android_layout_width="match_parent"
 android_layout_height="match_parent"
 android_padding="16dp"
 android_orientation="vertical"
 tools_context=".MainActivity">

 <TextView
 android_layout_width="wrap_content"
 android_layout_height="wrap_content"
 android_layout_gravity="center_horizontal"
 android_autoLink="web"
 android_text="http://android-er.blogspot.com/"
 android_textStyle="bold" />

 <EditText
 android_id="@+id/cityname"
 android_layout_width="match_parent"
 android_layout_height="wrap_content"
 android_hint="City name"/>
 <Button
 android_id="@+id/bycityname"
 android_layout_width="match_parent"
 android_layout_height="wrap_content"
 android_text="Call current weather by city name"/>
 <LinearLayout
 android_layout_width="match_parent"
 android_layout_height="match_parent"
 android_orientation="horizontal">
 <ScrollView
 android_layout_width="0dp"
 android_layout_height="match_parent"
 android_layout_weight="1">
 <TextView
 android_id="@+id/result"
 android_layout_width="match_parent"
 android_layout_height="wrap_content"
 android_textSize="20dp"
 android_textStyle="bold"/>
 </ScrollView>
 <ScrollView
 android_layout_width="0dp"
 android_layout_height="match_parent"
 android_layout_weight="1">
 <TextView
 android_id="@+id/info"
 android_layout_width="match_parent"
 android_layout_height="wrap_content"
 android_textSize="18dp"
 android_textStyle="italic"/>
 </ScrollView>
 </LinearLayout>

</LinearLayout>

Permission of "android.permission.INTERNET" is needed in AndroidManifest.xml.

 <uses-permission android_name="android.permission.INTERNET"/>

Download the files (Android Studio Format) .

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Free eBook Android Quick Start Guide Android 6 0 Marshmallow

Free from Google Play - Android Quick Start Guide, Android 6.0 (Marshmallow). Introduces Android 6.0 (Marshmallow) for Nexus and Android One devices. Available globally. For complete online help, see https://goo.gl/e178JT.

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Ninja Village Android Free

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