Tactile feedback

Touch devices provide tactile feedback when the user interacts with the touch screen. Tactile feedback consists of small signs (audio, vibration) that accompany touch events. These signs provide immediate physical confirmation that a touch event has been registered. Tactile feedback thus enables a more responsive interaction experience by eliminating the passive feeling of touch UIs.

Tactile feedback is provided for all touch events. As a rule, tactile feedback is triggered every time the user interacts with the touch UI. For example, the device provides tactile feedback when the user touches a button and also when the user releases touch. When a slider is used, the device provides continuous tactile feedback. MIDlets provide tactile feedback in a manner similar to native applications.

Like audio, use tactile feedback carefully so as not to desensitize the user to the effect. The attention-grabbing quality of tactile feedback is maintained only as long as the feedback is not too frequent.

In MIDlets, tactile feedback is supported since Series 40 6th Edition FP1 and Java Runtime 1.3 for S60. Users can enable and disable tactile feedback from the device settings.

Tactile feedback with high-level UI components

On Series 40 and Symbian devices, if enabled, tactile feedback works automatically with all high-level LCDUI components. On Symbian devices, tactile feedback also works automatically with all high-level eSWT components.

MIDlets cannot enable or disable tactile feedback for high-level UI components.

Tactile feedback with low-level UI components

On Series 40 devices, if enabled, tactile feedback works automatically with all low-level LCDUI components. MIDlets cannot enable or disable tactile feedback for these components.

On Symbian devices, low-level LCDUI and eSWT components do not automatically support tactile feedback. For these components, you need to separately implement tactile feedback by using the TactileFeedback class of the Nokia UI API. The device's native tactile feedback settings do not affect low-level UI components.

Note: The Series 40 platform provides a stub implementation of the TactileFeedback class. This means that you can call the class methods in your MIDlet, but they provide no functionality on a Series 40 device. So, even though you cannot actually use this feature on a Series 40 device, you can compile the MIDlet with the method calls in place. The stub implementation is supported from Series 40 6th Edition FP1 onwards. Earlier Series 40 releases do not support the class in any form.

On a Symbian device, to determine whether the device supports the TactileFeedback class, use the com.nokia.mid.ui.tactilefeedback system property.

TactileFeedback allows you to create tactile feedback in two ways:

  • By directly generating tactile feedback in response to a specific touch action

  • By defining screen areas that provide tactile feedback automatically when touched

While predefined screen areas only provide tactile feedback on touch down events (pointerPressed in LCDUI and mouseDown in eSWT), direct feedback allows you to fully control what kind of user interaction triggers the feedback. However, if feedback latency is an issue, use area-based feedback, since it guarantees minimum latency.

To provide tactile feedback for low-level LCDUI and eSWT components:

Note: The following code snippets assume that you have already created the necessary UI components and defined touch event handlers for them.

  1. Create a TactileFeedback object instance:

    TactileFeedback tactileFeedback = new TactileFeedback();

  2. Check whether the device supports tactile feedback:

    if (tactileFeedback.isTouchFeedbackSupported()) {

    // if tactile feedback is supported

} else {

    // if tactile feedback is not supported

}

  3. Implement tactile feedback in the touch event handlers:

    • If you want to provide direct feedback, use the directFeedback method.

      Tip: You can also define direct feedback for high-level UI components, since the directFeedback method merely triggers tactile feedback on the device, irrespective of what UI component is selected.

    • If you want to provide area-based feedback, use the registerFeedbackArea method.

© Nokia 2011.