Qml Weather

By default the application uses static test data to mimic a weather forecast. You can also obtain an application id from http://www.worldweatheronline.com/ to get access to weather API provided by World Weather Online. You can then give your application id as a parameter to the Qml Weather executable to make it use live data.

For example:

 bin\qmlweather.exe 1234567890abcdef123456

Running the Example

To run the example from Qt Creator, open the Welcome mode and select the example from Examples. For more information, visit Building and Running an Example.

Using Charts in Qt Quick Applications

The example application uses a ChartView and a some series to visualize weather data:

 ChartView {
     id: chartView
     title: "Weather forecast"
     BarCategoryAxis {
         id: barCategoriesAxis
         titleText: "Date"
     }

     ValueAxis{
         id: valueAxisY2
         min: 0
         max: 10
         titleText: "Rainfall [mm]"
     }

     ValueAxis {
         id: valueAxisX
         // Hide the value axis; it is only used to map the line series to bar categories axis
         visible: false
         min: 0
         max: 5
     }

     ValueAxis{
         id: valueAxisY
         min: 0
         max: 15
         titleText: "Temperature [°C]"
     }

     LineSeries {
         id: maxTempSeries
         axisX: valueAxisX
         axisY: valueAxisY
         name: "Max. temperature"
     }

     LineSeries {
         id: minTempSeries
         axisX: valueAxisX
         axisY: valueAxisY
         name: "Min. temperature"
     }

     BarSeries {
         id: myBarSeries
         axisX: barCategoriesAxis
         axisYRight: valueAxisY2
         BarSet {
             id: rainfallSet
             label: "Rainfall"
         }
     }

To get data with weather forecast data, we make an HTTP GET request to World Weather Online. We request the response in JSON data format.

 // Make HTTP GET request and parse the result
 var xhr = new XMLHttpRequest;
 xhr.open("GET",
          "http://free.worldweatheronline.com/feed/weather.ashx?q=Jyv%c3%a4skyl%c3%a4,Finland&format=json&num_of_days=5&key="
          + weatherAppKey);
 xhr.onreadystatechange = function() {
     if (xhr.readyState == XMLHttpRequest.DONE) {
         var a = JSON.parse(xhr.responseText);
         parseWeatherData(a);
     }
 }
 xhr.send();

The JSON response contains an array of forecast data:

 // Loop through the parsed JSON
 for (var i in weatherData.data.weather) {
     var weatherObj = weatherData.data.weather[i];

That is then used as input data for our series and a ListModel we use as a container for weather icon URLs:

 // Store temperature values, rainfall and weather icon.
 // The temperature values begin from 0.5 instead of 0.0 to make the start from the
 // middle of the rainfall bars. This makes the temperature lines visually better
 // synchronized with the rainfall bars.
 maxTempSeries.append(Number(i) + 0.5, weatherObj.tempMaxC);
 minTempSeries.append(Number(i) + 0.5, weatherObj.tempMinC);
 rainfallSet.append(i, weatherObj.precipMM);
 weatherImageModel.append({"imageSource":weatherObj.weatherIconUrl[0].value});

Example project @ code.qt.io