Navigation is critical to a good user experience on a mobile phone.

Mobile phones have small screens which can only display limited data. To convey a lot of information quickly, the user must navigate through a number of pages. This should therefore be easy and obvious. biNu has been designed so that all navigation can be achieved as quickly and painlessly as possible. Navigation is therefore supported in two ways:

• Using the number keys plus the 2 standard softkeys beneath the screen as ‘shortcut’ keys.
• Using the scroll keys for navigating up and down or left and right between all defined links on the page.

There is no fiddly pointer to move around the screen. Note also that the phone’s scroll keys are also used to scroll down to see hidden content on a long page. The way this works is that the page starts to scroll if the user clicks the down scroll button after selecting the last link in the visible page. Scrolling left and right across pages is possible but discouraged because it is tedious and confusing; providing a poor user experience.

Function Keys can be programmed in 4 ways, usually for navigation:

• Links (similar to hrefs in HTML) can be defined anywhere in the content using the definition.  When these are encountered they are automatically assigned a number (between1-9) and are activated by pressing a number on the key pad.
• Specific keys can be programmed in the section of a binu XML page using the definition. These key assignments are not displayed on the screen.
• A pop-up Menu can be defined in the section.  A list of key assignments is displayed on the screen.
• Navigation keys (up, down, left and right) are allocated automatically based on the layout of content and the execution of the pages.

Special Actions

biNu supports some special Navigation actions that are defined using the ActionType attribute of the and properties:

• ‘Back’ Navigation – navigates to the previous page
• ‘Home’ Navigation – navigates to a ‘home’ page. The ‘home’ page is specified in the biNu configuration and cannot be controlled by the Application Developer. It is usually the first page the user saw when they entered biNu.
• ‘AppHome’ Navigation – navigates to a ‘home’ page that can be specified by the Application Developer for the app. If the Application Home has not been specified the page redirects to the biNu 'home' page.
• ‘AppExit’ Navigation – navigates to the page from which the user most recently navigated into the application.

Example:

    <actions>
        <action key="navigate" actionType="back" />

        <action key="select" actionType="home" />
    </actions>

Usage:

• Back navigates the user to the previous page not the previous impression. Usually navigation is to the last impression on that page.
• If the page uses Proxy Scrolling the user will return to the top of the page.
• The user can traverse back through a history of pages providing each page has a ‘Back’ action defined. If the user goes to a page without a ‘Back’ action the chain is broken and the back history is reset.
• If the user travels ‘back’ to a page the normal refresh rules determine if the page is checked for expiry and refreshed. Generally if the user goes back to the top impression of a page its expiry will be checked. If the impression is down a page expiry is not checked.