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AI 149494: Minor improvements to wording in design tips for missing activity and notifications

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See latest document at:
  http://doog:9000/guide/practices/ui_guidelines/activity_task_design.html

Automated import of CL 149494
This commit is contained in:
Doug Kramer
2009-06-02 12:17:49 -07:00
committed by The Android Open Source Project
parent 7363e049ec
commit b33940abca
1 changed files with 55 additions and 40 deletions
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95
docs/html/guide/practices/ui_guidelines/activity_task_design.jd
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@ -34,11 +34,11 @@ page.title=Activity and Task Design Guidelines
<li><a href=#tips>Design Tips
<ol>
<li><a href=#activity_not_reused_tip>Don't specify intent filters in an activity that won't be re-used</a></li>
<li><a href=#others_to_reuse_tip>Don't define your own URI schemes</a></li>
<li><a href=#reusing_tip>Handle where a re-used activity is missing</a></li>
<!-- <li><a href=#others_to_reuse_tip>Don't define your own URI schemes</a></li> -->
<li><a href=#reusing_tip>Handle case where no activity matches</a></li>
<li><a href=#activity_launching_tip>Consider how to launch your activities</a></li>
<li><a href=#activities_added_to_task_tip>Allow activities to add to current task</a></li>
<li><a href=#notifications_return_tip>Notifications should be easy to return from</a></li>
<li><a href=#notifications_get_back_tip>Notifications should let user easily get back</li>
<li><a href=#use_notification_tip>Use the notification system</a></li>
<li><a href=#taking_over_back_key>Don't take over BACK key unless you absolutely need to</a></li>
</ol>
@ -49,7 +49,6 @@ page.title=Activity and Task Design Guidelines
<ol>
<li><a href="{@docRoot}guide/topics/fundamentals.html">Application Fundamentals</a></li>
<li><a href="http://android-developers.blogspot.com/2009/05/activities-and-tasks.html">Activities and Tasks blog post</a></li>
</ol>
</div>
@ -630,12 +629,12 @@ page.title=Activity and Task Design Guidelines
<p>
When the user takes an action on some data, such as touching a
mailto:info@example.com link, they are actually initiating an Intent
object which then gets resolved to a particular component (we will
consider only activity components here). So, the result of a user
touching a mailto: link is an Intent object that the system tries to
match to an activity. If that Intent object was written explicitly
naming an activity (an <em>explicit intent</em>), then the system
immediately launches that activity in response to the user
object, or just an <em>intent</em>, which then gets resolved to a
particular component (we consider only activity components here).
So, the result of a user touching a mailto: link is an Intent object
that the system tries to match to an activity. If that Intent object was
written explicitly naming an activity (an <em>explicit intent</em>),
then the system immediately launches that activity in response to the user
action. However, if that Intent object was written without naming an
activity (an <em>implicit intent</em>), the system compares the Intent
object to the <em>intent filters</em> of available activities. If more
@ -872,12 +871,29 @@ page.title=Activity and Task Design Guidelines
<p>
Your applications can re-use activities made available from other
applications. In doing so, you cannot presume that external activity
will always be present &mdash; you must handle the case that the
external activity is not installed. Do this in the way you find most
appropriate, such as dimming the user control that accesses it (such
as a button or menu item), or displaying a message to the user that
sends them to the location to download it, such as the Market.
applications. In doing so, you cannot presume your intent will always
be resolved to a matching external activity &mdash; you must handle the case
where no application installed on the device can handle the intent.
</p>
<p>
You can either test that an activity matches the intent, which you can do
before starting the activity, or catch an exception if starting the
activity fails. Both approaches are descibed in the blog posting
<a href="http://android-developers.blogspot.com/2009/01/can-i-use-this-intent.html">Can
I use this Intent?</a>.
</p>
<p>
To test whether an intent can be resolved, your code can query the package manager.
The blog post provides an example in the isIntentAvailable() helper method.
You can perform this test when initializing the user interface.
For instance, you could disable the user control that initiates
the Intent object, or display a message to the user that lets them go
to a location, such as the Market, to download its application.
In this way, your code can start the activity (using either startActivity()
or startActivityForResult()) only if the intent has tested to resolve
to an activity that is actually present.
</p>
<h3 id=activity_launching_tip>Consider how you want your activities to be launched or used by other applications</h3>
@ -1054,15 +1070,14 @@ page.title=Activity and Task Design Guidelines
</p>
<h3 id="notifications_return_tip">Notifications should be easy for the user to return from</h3>
<h3 id="notifications_get_back_tip">Notifications should let the user easily get back to the previous activity</h3>
<p>
Applications that are in the background or haven't been run can
send out notifications to the user letting them know about events
of interest. For example, Calendar can send out notifications of
upcoming events, and Email can send out notifications when new
messages arrive. One of the user interface rules is that when the
user is in activity A and gets a notification for activity B and
Applications that are in the background or not running can have
services that send out notifications to the user letting them know about
events of interest. Two examples are Calendar, which can send out notifications of
upcoming events, and Email, which can send out notifications when new
messages arrive. One of the user interface guidelines is that when the
user is in activity A, gets a notification for activity B and
picks that notification, when they press the BACK key, they should
go back to activity A.&nbsp;
</p>
@ -1108,11 +1123,11 @@ Notifications generally happen primarily in one of two ways:
<ul>
<li>
<b>The application has a dedicated activity for
notification</b> - For example, when the user receives a
Calendar notification, the act of selecting that
<b>The chosen activity is dedicated for notification only</b> -
For example, when the user receives a
Calendar notification, choosing that
notification starts a special activity that displays a list
of upcoming calendar events &mdash; a view available only
of upcoming calendar events &mdash; this view is available only
from the notification, not through the Calendar's own user
interface. After viewing this upcoming event, to ensure that
the user pressing the BACK key will return to the activity
@ -1140,25 +1155,25 @@ Notifications generally happen primarily in one of two ways:
</li>
<li>
<b>The user choosing the notification brings the activity to
<b>The chosen activity is not dedicated, but always comes to
the foreground in its initial state</b> - For example, in
response to a notification, the Gmail application is brought
to the foreground presenting the list of conversations. You
do this by having the user's response to the notification
trigger an intent to launch the activity with the clear top
flag set. (That is, you put {@link
response to a notification, when the Gmail application comes
to the foreground, it always presents the list of conversations.
You can ensure this happens by setting a "clear top" flag in the
intent that the notification triggers. This ensures that when the
activity is launched, it displays its initial activity, preventing
Gmail from coming to the foreground in whatever state the user last
happened to be viewing it. (To do this, you put {@link
android.content.Intent#FLAG_ACTIVITY_CLEAR_TOP
FLAG_ACTIVITY_CLEAR_TOP} in the intent you pass to
startActivity()). This prevents Gmail from coming to the
foreground in whatever state the user last happened to be
viewing it.
FLAG_ACTIVITY_CLEAR_TOP} in the intent you pass to startActivity()).
</li>
</ul>
<p>
There are other ways to handle notifications, such as bringing the
activity to the foreground set to display specific data, such as the
ongoing text message thread of a particular person.
activity to the foreground, set to display specific data, such as
displaying the text message thread for the person who just sent a
new text message.
</p>
<p>