Using Indicators to Display Data to Users

The Android SDK provides a number of controls that can be used to visually show some form of information to the user. These indicator controls include progress bars, clocks, and other similar controls.

Indicating Progress with ProgressBar

Applications commonly perform actions that can take a while. A good practice during this time is to show the user some sort of progress indicator that informs the user that the application is off “doing something.” Applications can also show how far a user is through some operation, such as a playing a song or watching a video. The Android SDK provides several types of progress bars.

The standard progress bar is a circular indicator that only animates. It does not show how complete an action is. It can, however, show that something is taking place. This is useful when an action is indeterminate in length. There are three sizes of this type of progress indicator (see Figure 8.9).