practices/ui_guidelines/widget_design.jd

page.title=Widget Design Guidelines
@jd:body

<div id="qv-wrapper">
<div id="qv">

<h2>Widget design quickview</h2>

<ul>
<li>Widgets have six standard sizes on the Home screen</li>
<li>Widgets have standards for size, frames, shadows, and file format, which you can copy</li>
<li>A few tricks make it easier to design widgets that fit graphically on the Home screen</li>
</ul>

<h2>In this document</h2>

<ol>
<li><a href="#anatomy">Standard widget anatomy</a></li>
<li><a href="#design">Designing a widget</a></li>
<li><a href="#sizes">Standard widget sizes</a></li>
<li><a href="#frames">Standard widget frames</a></li>
<li><a href="#shadows">Standard widget shadows</a></li>
<li><a href="#tricks">Widget graphics tips and tricks</a></li>
<li><a href="#file">Widget graphics file format</a></li>
</ol>

<h2>See also</h2>

<ol>
<li><a href="{@docRoot}guide/topics/appwidgets/index.html">AppWidgets</a> topic in the <em>Dev Guide</em></li>
<li><a href="http://android-developers.blogspot.com/2009/04/introducing-home-screen-widgets-and.html">AppWidgets blog post</a></li>
</ol>

</div>
</div>


<p>Widgets are a feature introduced in Android 1.5. A widget displays an
application's most important or timely information at a glance, on a user's Home
screen. The standard Android system image includes several examples of widgets,
including widgets for Analog Clock, Music, and other applications.</p>

<p>Users pick the widgets they want to display on their Home screens by touching
&amp; holding an empty area of the Home screen, selecting Widgets from the menu,
and then selecting the widget they want.</p>

<p><img src="{@docRoot}images/widget_design/widget_examples.png" alt="Example
Widgets"></p>

<p>This document describes how to design a widget so it fits graphically with
other widgets and with the other elements of the Android Home screen. It also
describes some standards for widget artwork and some widget graphics tips and
tricks from the Android team.<p>

<p>For information about developing widgets, see the <a
href="{@docRoot}guide/topics/appwidgets/index.html">AppWidgets</a> section of
the <em>Developer's Guide</em> and the <a
href="http://android-developers.blogspot.com/2009/04/introducing-home-screen-widgets-and.html">AppWidgets</a> blog post.</p>


<h2 id="anatomy">Standard widget anatomy</h2>

<p>Typical Android widgets have three main components: A bounding box, a frame,
and the widget's graphical controls and other elements. Well-designed widgets
leave some padding between the edges of the bounding box and the frame, and
between the inner edges of the frame and the widget's controls. Widgets designed
to fit visually with other widgets on the Home screen take cues from the other
elements on the Home screen for alignment; they also use standard shading
effects. All of these details are described in this document.

<p><strong>Standard Widget Sizes in Portrait Orientation</strong><br/>
<img src="{@docRoot}images/widget_design/widget_sizes_portrait.png"
alt="Standard Widget Sizes in Portrait Orientation"></p>

<p>&nbsp;</p>

<p><strong>Standard Widget Sizes in Landscape Orientation</strong><br/>
<img src="{@docRoot}images/widget_design/widget_sizes_landscape.png"
alt="Standard Widget Sizes in Landscape Orientation"></p>


<h2 id="design">Designing a widget</h2>

<ol>
<li><strong>Select a bounding box size for your widget.</strong></li>

<p>The most effective widgets display your application's most useful or timely
data in the smallest widget size. Users will weigh the usefulness or your widget
against the portion of the Home screen it covers, so the smaller the better.</p>

<p>All widgets must fit within the bounding box of one of the six supported
widget sizes, or better yet, within a pair of portrait and landscape orientation
sizes, so your widget looks good when the user switches screen
orientations.</p>

<p><a href="#sizes">Standard widget sizes</a> illustrates the bounding
dimensions of the six widget sizes (three in portrait and three in landscape
orientation).</p>


<li><strong>Select a matching frame.</strong></li>

<p><a href="#frames">Standard widget frames</a> illustrates the standard frames
for the six widget sizes, with links so you can download copies for your own
use. You don't have to use these frames for your widget, but if you do, your
widgets are more likely to fit visually with other widgets.</p>

<li><strong>Apply standard shadow effect to your graphics.</strong></li>

<p>Again, you don't have to use this effect, but <a href="#shadows">Standard
widget shadows</a> shows the Photoshop settings used for standard widgets.</p>

<li><strong>If your widget includes buttons,  draw them in three states
(default, pressed, and selected).</strong></li>

<p>You can <a
href="{@docRoot}images/widget_design/Music_widget_button_states.psd">download a
Photoshop file that contains the three states of the Play button</a>, taken from
the Music widget, to analyze the Photoshop settings used for the three standard
button effects.</p>

<p><a href="{@docRoot}images/widget_design/Music_widget_button_states.psd"> <img
src="{@docRoot}images/widget_design/buttons.png" alt="Click to download
Photoshop template"></a></p>

<li><strong>Finish drawing your artwork and then scale and align it to
fit.</strong></li>

<p><a href="#tricks">Widget alignment tips and tricks</a> describes some
techniques for aligning your widget's graphics inside the standard frames, along
with a few other widget graphics tricks.</p>

<li><strong>Save your widget with the correct graphics file
settings.</strong></li>

<p><a href="#file">Windows graphics file format</a> describes the correct
settings for your widget graphics files.</p>

</ol>


<h2 id="sizes">Standard widget sizes</h2>

<p>There are six standard widget sizes, based on a Home screen grid of 4 x 4
(portrait) or 4 x 4 (landscape) cells. These dimensions are the bounding boxes
for the six standard widget sizes. The contents of typical widgets don't draw to
the edge of these dimensions, but fit inside a frame withing the bounding box,
as described in <a href="#design">Designing a widget</a>.</p>

<p>In portrait orientation, each cell is 80 pixels wide by 100 pixels tall (the
diagram shows a cell in portrait orientation). The three supported widget sizes
in portrait orientation are:<p>

<table>
<tr><th>Cells</th><th>Pixels</th></tr>
<tr><td>4 x 1</td><td>320 x 100</td></tr>
<tr><td>3 x 3</td><td>240 x 300</td></tr>
<tr><td>2 x 2</td><td>160 x 200</td></tr>
</table>

<p><img src="{@docRoot}images/widget_design/portrait_sizes.png" alt="Widget
dimensions in portrait orientation"></p>

<p>In landscape orientation, each cell is 106 pixels wide by 74 pixels tall. The
three supported widget sizes in landscape orientation are:</p>

<table>
<tr><th>Cells</th><th>Pixels</th></tr>
<tr><td>4 x 1</td><td>424 x 74</td></tr>
<tr><td>3 x 3</td><td>318 x 222</td></tr>
<tr><td>2 x 2</td><td>212 x 148</td></tr>
</table>

<p><img src="{@docRoot}images/widget_design/landscape_sizes.png" alt="Widget
dimensions in landscape orientation"></p>


<h2 id="frames">Standard widget frames</h2>

<p>For each of the six standard widget sizes there is a standard frame. You can
click the images of the frames in this section to download a Photoshop file for
that frame, which you can use for your own widgets.<p>

<p><a href="{@docRoot}images/widget_design/4x1_Widget_Frame_Portrait.psd"> <img
src="{@docRoot}images/widget_design/4x1_Widget_Frame_Portrait.png" alt="Click to
download"></a><br>4x1_Widget_Frame_Portrait.psd</p>

<p><a href="{@docRoot}images/widget_design/3x3_Widget_Frame_Portrait.psd"> <img
src="{@docRoot}images/widget_design/3x3_Widget_Frame_Portrait.png" alt="Click to
download"></a><br>3x3_Widget_Frame_Portrait.psd</p>

<p><a href="{@docRoot}images/widget_design/2x2_Widget_Frame_Portrait.psd"> <img
src="{@docRoot}images/widget_design/2x2_Widget_Frame_Portrait.png" alt="Click to
download"></a><br>2x2_Widget_Frame_Portrait.psd</p>

<p><a href="{@docRoot}images/widget_design/4x1_Widget_Frame_Landscape.psd"> <img
src="{@docRoot}images/widget_design/4x1_Widget_Frame_Landscape.png" alt="Click
to download"></a><br>4x1_Widget_Frame_Landscape.psd</p>

<p><a href="{@docRoot}images/widget_design/3x3_Widget_Frame_Landscape.psd"> <img
src="{@docRoot}images/widget_design/3x3_Widget_Frame_Landscape.png" alt="Click
to download"></a><br>3x3_Widget_Frame_Landscape.psd</p>

<p><a href="{@docRoot}images/widget_design/2x2_Widget_Frame_Landscape.psd"> <img
src="{@docRoot}images/widget_design/2x2_Widget_Frame_Landscape.png" alt="Click
to download"></a><br>2x2_Widget_Frame_Landscape.psd</p>


<h2 id="shadows">Standard widget shadows</h2>

<p>You can apply a shadow effect to your widget's artwork, so it matches other
standard Android widgets, using the following settings in the Photoshop Layer
Style dialog box.</p>

<p><img src="{@docRoot}images/widget_design/Layer_Style.png" alt="Layer Style
settings for standard shadows"></p>


<h2 id="tricks">Widget graphics tips and tricks</h2>

<p>The Android team has developed a few tricks for aligning widget artwork
within standard widget bounding boxes and frames, so the widget aligns visually
with other widgets and the other elements of the Home screen, as well as other
techniques for creating widgets.

<ul>

<li>Use a screen shot from the Android SDK emulator to align both the shapes and
shadows of your widget controls with the Search widget and with other elements
on the Home screen.</li>

<p>Cut the widget artwork asset" based on the full size of a cell, including any
padding you want. (That is, for a 4 x 1 widget, cut the asset at 320 by 100
pixels.)</p>

<p><img src="{@docRoot}images/widget_design/alignment.png" alt="Aligning widget
graphics" ></p>

<li>To reduce banding when exporting a widget, apply the following Photoshop Add
Noise setting to your graphic.</li>

<p><img src="{@docRoot}images/widget_design/Add_Noise.png" alt="Add Noise
settings for widget graphics" ></p>

<li>Apply 9-patch techniques to shrink the graphic and set the padding of the
content area. (<a href="{@docRoot}guide/developing/tools/draw9patch.html">See
the detailed guide here.</a>)</li>

<p><strong>Note:</strong> The current Android widget templates were designed
using a custom gradient angle, which means the 9-patch techniques can't be used
to optimize the size of the asset. However, 9-patch techniques were used to set
the content area padding.</p>

<li>In some cases, devices have low pixel depths that can cause visual banding
and dithering issues. To solve this, application developers should pass assets
through a "proxy" drawable defined as <code>XML:<nine-patch
android:src="@drawable/background" android:dither="true" /></code>. This
technique references the original artwork, in this case
<code>"background.9.png"</code>, and instructs the device to dither it as
needed.</li>

</ul>

<h2 id="file">Widget graphics file format</h2>

<p>Save your widget artwork using the appropriate bounding box size in PNG-24
format on a transparent background and in 8-bit color.</p>

<p><img src="{@docRoot}images/widget_design/file_format.png" alt="Widget graphics file format" ></p>