Книга: Beginning Android

Raising Toasts

Raising Toasts

A Toast is a transient message, meaning that it displays and disappears on its own without user interaction. Moreover, it does not take focus away from the currently active Activity, so if the user is busy writing the next Great American Programming Guide, they will not have keystrokes be “eaten” by the message.

Since a Toast is transient, you have no way of knowing if the user even notices it. You get no acknowledgment from them, nor does the message stick around for a long time to pester the user. Hence, the Toast is mostly for advisory messages, such as indicating a long-running background task is completed, the battery has dropped to a low-but-not-too-low level, etc.

Making a Toast is fairly easy. The Toast class offers a static makeText() that accepts a String (or string resource ID) and returns a Toast instance. The makeText() method also needs the Activity (or other Context) plus a duration. The duration is expressed in the form of the LENGTH_SHORT or LENGTH_LONG constants to indicate, on a relative basis, how long the message should remain visible.

If you would prefer your Toast be made out of some other View, rather than be a boring old piece of text, simply create a new Toast instance via the constructor (which takes a Context), then call setView() to supply it with the view to use and setDuration() to set the duration.

Once your Toast is configured, call its show() method, and the message will be displayed.

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