C H A P T E R 3

Controls

Button Behavior

Although text buttons and picture buttons look different, their basic behavior is the same. Both types of buttons provide similar feedback to the user, and an application disables both types the same way.

Button Feedback

When a user taps a text button or a picture button, the button highlights (inverts) to give visual feedback to the user that the item has been tapped. Figure 3-9 shows how several buttons look when highlighted.

Figure 3-9Tapping a button highlights it

Not highlighted

Highlighted

A button stays highlighted as long as the user continues to press the pen on that button. When the user lifts the pen from the highlighted button, the action associated with the button takes place. Your application must continue to highlight the button until the action is complete. In the case of a button that displays an ordinary slip (not a status slip), the button stays highlighted only until the slip appears. In the case of a button that pops up a picker (described in Chapter 4, “Pickers”), the button stays highlighted as long as any action initiated by the picker is in progress.

Keeping the button highlighted provides the minimal feedback to the user that Newton is still working. When an action begun by a button takes more than a few seconds, your application should provide more feedback by displaying a status slip that names the action underway (as described in “Status Slips” on page 2-20).

If your application uses buttons made from system protos, the system auto- matically adjusts button highlighting in response to a user’s pen movements. When a user slides the pen away from a highlighted button while still pressing

Buttons

3-9

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Apple 2 manual Button Behavior, Button Feedback
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2 specifications

The Apple II is a defining product in the history of personal computing, first introduced in 1977 by Apple Computer, Inc. Designed by Steve Wozniak, the Apple II was one of the first highly successful mass-produced microcomputer products and played a significant role in bringing personal computers into homes and schools.

One of the Apple II's standout features was its color graphics capability. It was one of the first personal computers to provide color output, thanks to its built-in video interface. The initial model supported a resolution of 280x192 pixels with a palette of 6 colors, which allowed for vibrant visuals that set it apart from contemporaries like the monochrome Altair 8800.

The Apple II was notable for its open architecture. This design allowed users to expand the computer's capabilities easily through a series of expansion slots. Users could add floppy disk drives, additional memory, and various peripheral devices, making the system highly adaptable to individual needs. This encouraged a thriving ecosystem of third-party hardware and software, which contributed to its popularity.

Another significant feature was its use of the 6502 microprocessor. This 8-bit CPU was not only affordable but also powerful for its time, allowing the Apple II to run various applications efficiently. Along with a built-in keyboard and an innovative plastic case that housed its components, the design was user-friendly and appealing.

The Apple II also introduced the concept of “bootable software” through the use of floppy disks. The disk operating system (DOS) allowed users to store and run multiple programs without having to reload software manually, providing a level of convenience that had not been widely available before. Key software like VisiCalc, the first spreadsheet program, helped boost sales, showcasing the Apple II's utility in business and education environments.

The computer was also well-known for its early adoption of BASIC programming language. Apple provided an operating system that supported Applesoft BASIC, which enabled users, including students, to write their programs, further fostering a community of developers.

In summary, the Apple II's color graphics, open architecture, powerful 6502 processor, innovative use of floppy disks, and support for BASIC programming made it a revolutionary product in its time. Its legacy laid the groundwork for future personal computers and established Apple as a leader in the burgeoning tech industry. The Apple II remains an iconic symbol of the early personal computing era, reflecting a generation's transition into a digitally connected world.
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