Compass

Compass

Obtains the direction that the device is pointing.

Methods

Arguments


compass.getCurrentHeading

Get the current compass heading.

navigator.compass.getCurrentHeading(compassSuccess, compassError, compassOptions);

Description

The compass is a sensor that detects the direction or heading that the device is pointed. It measures the heading in degrees from 0 to 359.99.

The compass heading is returned using the compassSuccess callback function.

Supported Platforms

Quick Example

function onSuccess(heading) {
    alert('Heading: ' + heading);
};

function onError() {
    alert('onError!');
};

navigator.compass.getCurrentHeading(onSuccess, onError);

Full Example

<!DOCTYPE html>
<html>
  <head>
    <title>Compass Example</title>

    <script type="text/javascript" charset="utf-8" src="phonegap.js"></script>
    <script type="text/javascript" charset="utf-8">

    // Wait for PhoneGap to load
    //
    document.addEventListener("deviceready", onDeviceReady, false);

    // PhoneGap is ready
    //
    function onDeviceReady() {
        navigator.compass.getCurrentHeading(onSuccess, onError);
    }

    // onSuccess: Get the current heading
    //
    function onSuccess(heading) {
        alert('Heading: ' + heading);
    }

    // onError: Failed to get the heading
    //
    function onError() {
        alert('onError!');
    }

    </script>
  </head>
  <body>
    <h1>Example</h1>
    <p>getCurrentHeading</p>
  </body>
</html>

compass.watchHeading

At a regular interval, get the compass heading in degrees.

var watchID = navigator.compass.watchHeading(compassSuccess, compassError, [compassOptions]);

Description

The compass is a sensor that detects the direction or heading that the device is pointed. It measures the heading in degrees from 0 to 359.99.

The compass.watchHeading gets the device's current heading at a regular interval. Each time the heading is retrieved, the headingSuccess callback function is executed. Specify the interval in milliseconds via the frequency parameter in the compassOptions object.

The returned watch ID references references the compass watch interval. The watch ID can be used with compass.clearWatch to stop watching the compass.

Supported Platforms

Quick Example

function onSuccess(heading) {
    var element = document.getElementById('heading');
    element.innerHTML = 'Heading: ' + heading;
};

function onError() {
    alert('onError!');
};

var options = { frequency: 3000 };  // Update every 3 seconds

var watchID = navigator.compass.watchHeading(onSuccess, onError, options);

Full Example

<!DOCTYPE html>
<html>
  <head>
    <title>Compass Example</title>

    <script type="text/javascript" charset="utf-8" src="phonegap.js"></script>
    <script type="text/javascript" charset="utf-8">

    // The watch id references the current `watchHeading`
    var watchID = null;

    // Wait for PhoneGap to load
    //
    document.addEventListener("deviceready", onDeviceReady, false);

    // PhoneGap is ready
    //
    function onDeviceReady() {
        startWatch();
    }

    // Start watching the compass
    //
    function startWatch() {

        // Update compass every 3 seconds
        var options = { frequency: 3000 };

        watchID = navigator.compass.watchHeading(onSuccess, onError, options);
    }

    // Stop watching the compass
    //
    function stopWatch() {
        if (watchID) {
            navigator.compass.clearWatch(watchID);
            watchID = null;
        }
    }

    // onSuccess: Get the current heading
    //
    function onSuccess(heading) {
        var element = document.getElementById('heading');
        element.innerHTML = 'Heading: ' + heading;
    }

    // onError: Failed to get the heading
    //
    function onError() {
        alert('onError!');
    }

    </script>
  </head>
  <body>
    <div id="heading">Waiting for heading...</div>
    <button onclick="startWatch();">Start Watching</button>
    <button onclick="stopWatch();">Stop Watching</button>
  </body>
</html>

compass.clearWatch

Stop watching the compass referenced by the watch ID parameter.

navigator.compass.clearWatch(watchID);

Supported Platforms

Quick Example

var watchID = navigator.compass.watchHeading(onSuccess, onError, options);

// ... later on ...

navigator.compass.clearWatch(watchID);

Full Example

<!DOCTYPE html>
<html>
  <head>
    <title>Compass Example</title>

    <script type="text/javascript" charset="utf-8" src="phonegap.js"></script>
    <script type="text/javascript" charset="utf-8">

    // The watch id references the current `watchHeading`
    var watchID = null;

    // Wait for PhoneGap to load
    //
    document.addEventListener("deviceready", onDeviceReady, false);

    // PhoneGap is ready
    //
    function onDeviceReady() {
        startWatch();
    }

    // Start watching the compass
    //
    function startWatch() {

        // Update compass every 3 seconds
        var options = { frequency: 3000 };

        watchID = navigator.compass.watchHeading(onSuccess, onError, options);
    }

    // Stop watching the compass
    //
    function stopWatch() {
        if (watchID) {
            navigator.compass.clearWatch(watchID);
            watchID = null;
        }
    }

    // onSuccess: Get the current heading
    //
    function onSuccess(heading) {
        var element = document.getElementById('heading');
        element.innerHTML = 'Heading: ' + heading;
    }

    // onError: Failed to get the heading
    //
    function onError() {
        alert('onError!');
    }

    </script>
  </head>
  <body>
    <div id="heading">Waiting for heading...</div>
    <button onclick="startWatch();">Start Watching</button>
    <button onclick="stopWatch();">Stop Watching</button>
  </body>
</html>

compassSuccess

onSuccess callback function that provides the compass heading information.

function(heading) {
    // Do something
}

Parameters

Example

function onSuccess(heading) {
    alert('Heading: ' + heading);
};

compassError

onError callback function for compass functions.

function() {
    // Handle the error
}

compassOptions

An optional parameter to customize the retrieval of the compass.

Options