Event Handling

The Tizen platform supports event handling for user interactions. To provide a full user experience for your application users, you must handle various events in your application.

This feature is supported in wearable applications only.

Rotary events

The Tizen platform supports rotary events for user interaction on a wearable rotary device or sensor. The rotary device can rotate clockwise or counter-clockwise, and dispatch an event for each movement. The rotary device has points called detent. If the rotary device detects the detent point while rotating, it dispatches a separate new event about the point. The number of the available detent points depends on the device hardware.

Figure: Rotary device

Rotary events are used to deliver the rotary device or sensor data to the application. The following table describes the rotary events.

Table: Rotary events

To bind an event callback on rotary events, use the following code:

document.addEventListener('rotarydetent', function(ev) {
    /* Get the direction value from the event */
    var direction = ev.detail.direction;

    if (direction == 'CW') {
        /* Add behavior for clockwise rotation */
        console.log('clockwise');
    } else if (direction == 'CCW') {
        /* Add behavior for counter-clockwise rotation */
        console.log('counter-clockwise');
    }
});

Ambient events

On a low-powered wearable device, an ambient mode is available for watch applications. To reduce power consumption, a Tizen watch application displayed on the idle screen in ambient mode can show a limited UI and receives only the ambient tick event every minute.

The details of the limited UI drawn in the ambient mode depend on the device. In addition, due to the ambient mode being a low-power mode, there are limits to the colors that can be shown on the screen. Usually, when designing the ambient mode UI, draw it with limited colors (cyan, magenta, yellow, red, green, blue, black and white), and use less than 15% of the pixels on the screen. If you do not want to draw your own ambient mode UI, set the ambient_support attribute to disable in the watch application config.xml file to allow the platform to show a default ambient mode UI.

Since Tizen 2.3.2, some devices introduce a high color mode for the ambient mode. In the high color mode, you can use more colors (usually, 24-bit color) for drawing the ambient mode UI. To check whether the device supports the high color mode, use the following code:

/* Check whether high color mode is supported */
var isHighColorMode = tizen.systeminfo.getCapability('http://tizen.org/feature/screen.always_on.high_color');

Note

To use the ambient mode, the user must enable it in the device settings. In addition, on the Gear S2 device, the ambient mode activates only when you are wearing the watch on the wrist.

The following table describes the ambient mode events.

Table: Ambient events

To bind an event callback on ambient events, use the following code:

document.addEventListener('ambientmodechanged', function(ev) {
    var mode = ev.detail.ambientMode;
    if (mode == true) {
        /* Change the UI for ambient mode */
    } else {
        /* Change the UI for normal mode */
    }
});

document.addEventListener('timetick', function(ev) {
    /* Update the UI */
});