102 lines
4.5 KiB
Plaintext
102 lines
4.5 KiB
Plaintext
page.title=Notifying the User
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@jd:body
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<div id="qv-wrapper">
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<div id="qv">
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<h2>Topics</h2>
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<ol>
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<li><a href="toasts.html">Creating Toast Notifications</a></li>
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<li><a href="notifications.html">Creating Status Bar Notifications</a></li>
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<li><a href="{@docRoot}guide/topics/ui/dialogs.html">Creating Dialogs</a></li>
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</ol>
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</div>
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</div>
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<p>Several types of situations may arise that require you to notify the user
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about an event that occurs in your application. Some events require the user to respond
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and others do not. For example:</p>
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<ul>
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<li>When an event such as saving a file is complete, a small message
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should appear to confirm that the save was successful.</li>
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<li>If the application is running in the background and needs the user's attention,
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the application should create a notification that allows the user to respond at
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his or her convenience.</li>
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<li>If the application is
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performing work that the user must wait for (such as loading a file),
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the application should show a hovering progress wheel or bar.</li>
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</ul>
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<p>Each of these notification tasks can be achieved using a different technique:</p>
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<ul>
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<li>A <a href="#Toast">Toast Notification</a>, for brief messages that come
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from the background.</li>
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<li>A <a href="#StatusBar">Status Bar Notification</a>, for persistent reminders
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that come from the background and request the user's response.</li>
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<li>A <a href="#Dialog">Dialog Notification</a>, for Activity-related notifications.</li>
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</ul>
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<p>This document summarizes each of these techniques for notifying the user and includes
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links to full documentation.</p>
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<h2 id="Toast">Toast Notification</h2>
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<img src="{@docRoot}images/toast.png" alt="" style="float:right" />
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<p>A toast notification is a message that pops up on the surface of the window.
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It only fills the amount of space required for the message and the user's current
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activity remains visible and interactive. The notification automatically fades in and
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out, and does not accept interaction events. Because a toast can be created from a background
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{@link android.app.Service}, it appears even if the application isn't visible.</p>
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<p>A toast is best for short text messages, such as "File saved,"
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when you're fairly certain the user is paying attention
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to the screen. A toast can not accept user interaction events; if you'd like
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the user to respond and take action, consider using a
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<a href="#StatusBar">Status Bar Notification</a> instead.</p>
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<p>For more information, refer to <a href="toasts.html">Creating Toast Notifications</a>.</p>
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<h2 id="StatusBar">Status Bar Notification</h2>
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<img src="{@docRoot}images/notifications_window.png" alt="" style="float:right; clear:right;" />
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<p>A status bar notification adds an icon to the system's status bar
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(with an optional ticker-text message) and an expanded message in the "Notifications" window.
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When the user selects the expanded message, Android fires an
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{@link android.content.Intent} that is defined by the notification (usually to launch an
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{@link android.app.Activity}).
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You can also configure the notification to alert the user with a sound, a vibration, and flashing
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lights on the device.</p>
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<p>This kind of notification is ideal when your application is working in
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a background {@link android.app.Service} and needs to
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notify the user about an event. If you need to alert the user about an event that occurs
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while your Activity is still in focus, consider using a
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<a href="#Dialog">Dialog Notification</a> instead.</p>
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<p>For more information, refer to
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<a href="notifications.html">Creating Status Bar Notifications</a>.</p>
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<h2 id="Dialog">Dialog Notification</h2>
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<img src="{@docRoot}images/dialog_progress_spinning.png" alt="" style="float:right" />
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<p>A dialog is usually a small window that appears in front of the current Activity.
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The underlying Activity loses focus and the dialog accepts all user interaction.
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Dialogs are normally used
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for notifications and short activities that directly relate to the application in progress.</p>
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<p>You should use a dialog when you need to show a progress bar or a short
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message that requires confirmation from the user (such as an alert with "OK" and "Cancel" buttons).
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You can use also use dialogs as integral components
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in your application's UI and for other purposes besides notifications.
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For a complete discussion on all the available types of dialogs,
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including its uses for notifications, refer to
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<a href="{@docRoot}guide/topics/ui/dialogs.html">Creating Dialogs</a>.</p>
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