Quickview
-
-
- Widgets have six standard sizes on the Home screen -
- Widgets have standards for size, frames, shadows, and file format, which you can copy -
- A few tricks make it easier to design widgets that fit graphically on the Home screen +
- App Widget layouts should be flexible, resizing to fit their parent container +
- As of Android 3.0, app widgets can depict collections of items and provide a representative + preview image for the widget gallery +
- As of Android 3.1, app widgets can be resizable horizontally and/or vertically +
- As of Android 4.0, app widgets have margins automatically applied
In this document
-
-
- Standard widget anatomy -
- Designing a widget -
- Standard widget sizes -
- Standard widget frames -
- Standard widget shadows -
- Widget graphics tips and tricks -
- Widget graphics file format +
- Standard Widget Anatomy +
- Designing Widget Layouts and Background Graphics +
- Using the App Widget Templates Pack +
Downloads
+ +See also
-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.
+App widgets (sometimes just "widgets") are a feature introduced in Android 1.5 and vastly +improved in Android 3.0 and 3.1. A widget can display an application's most timely or otherwise +relevant information at a glance, on a user's Home screen. The standard Android system image +includes several widgets, including a widget for the Analog Clock, Music, and other +applications.
-Users pick the widgets they want to display on their Home screens by touching -& holding an empty area of the Home screen, selecting Widgets from the menu, -and then selecting the widget they want.
-
-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.
+
Figure 1. Example app widgets in Android 4.0.
+ + +This document describes how to design a widget so that it fits graphically with other widgets and +with the other elements of the Android Home screen such as launcher icons and shortcuts. It also +describes some standards for widget artwork and some widget graphics tips and tricks.
For information about developing widgets, see the AppWidgets section of -the Developer's Guide and the AppWidgets blog post.
+href="{@docRoot}guide/topics/appwidgets/index.html">App Widgets section of the Developer's +Guide. -Standard widget anatomy
+Standard Widget Anatomy
-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. - -
Standard Widget Sizes in Portrait Orientation
-
- -
Standard Widget Sizes in Landscape Orientation
-
Designing a widget
- --
-
- Select a bounding box size for your widget. - -
- Select a matching frame. +
- Apply standard shadow effect to your graphics. - -
- If your widget includes buttons, draw them in three states -(default, pressed, and selected). - -
- Finish drawing your artwork and then scale and align it to -fit. - -
- Save your widget with the correct graphics file -settings. - -
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.
- -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.
- -Standard widget sizes illustrates the bounding -dimensions of the six widget sizes (three in portrait and three in landscape -orientation).
+Typical Android app widgets have three main components: A bounding box, a frame, and the widget's +graphical controls and other elements. App widgets can contain a subset of the View widgets in +Android; supported controls include text labels, buttons, and images. For a full list of available +Views, see the Creating the +App Widget Layout section in the Developer's Guide. Well-designed widgets leave some +margins between the edges of the bounding box and the frame, and padding between the inner edges of +the frame and the widget's controls.
-
-Standard widget frames 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.
- -Again, you don't have to use this effect, but Standard -widget shadows shows the Photoshop settings used for standard widgets.
- -You can download a -Photoshop file that contains the three states of the Play button, taken from -the Music widget, to analyze the Photoshop settings used for the three standard -button effects.
- -
Widget alignment tips and tricks describes some -techniques for aligning your widget's graphics inside the standard frames, along -with a few other widget graphics tricks.
- -Windows graphics file format describes the correct -settings for your widget graphics files.
- -Figure 2. Widgets generally have margins between the +bounding box and frame, and padding between the frame and widget controls.
-Standard widget sizes
+Note: As of Android 4.0, app widgets are automatically given +margins between the widget frame and the app widget's bounding box to provide better alignment with +other widgets and icons on the user's home screen. To take advantage of this strongly recommended +behavior, set your application's targetSdkVersion to 14 or +greater.
-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 Designing a widget.
+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.
-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:
-
| Cells | Pixels |
|---|---|
| 4 x 1 | 320 x 100 |
| 3 x 3 | 240 x 300 |
| 2 x 2 | 160 x 200 |
| # of Cells (Columns or Rows) |
+ Available Size (dp) ( minWidth or
+ minHeight) |
+
|---|---|
| 1 | +40dp | +
| 2 | +110dp | +
| 3 | +180dp | +
| 4 | +250dp | +
| … | +… | +
| n | +70 × n − 30 | +
In landscape orientation, each cell is 106 pixels wide by 74 pixels tall. The -three supported widget sizes in landscape orientation are:
- -| Cells | Pixels |
|---|---|
| 4 x 1 | 424 x 74 |
| 3 x 3 | 318 x 222 |
| 2 x 2 | 212 x 148 |
It is a good practice to be conservative with minWidth and minHeight,
+specifying the minimum size that renders the widget in a good default state. For an example of how
+to provide a minWidth and minHeight, suppose you have a music player
+widget that shows the currently playing song artist and title (vertically stacked), a
+Play button, and a Next button:
Standard widget frames
+
-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.
- -
4x1_Widget_Frame_Portrait.psd
3x3_Widget_Frame_Portrait.psd
2x2_Widget_Frame_Portrait.psd
4x1_Widget_Frame_Landscape.psd
3x3_Widget_Frame_Landscape.psd
2x2_Widget_Frame_Landscape.psd
Figure 3. An example music player widget.
-Standard widget shadows
- -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.
- -
Your minimum height should be the height of your two TextViews for the artist and title, plus +some text margins. Your minimum width should be the minimum usable widths of the +Play and Next buttons, plus the minimum text width (say, the width +of 10 characters), plus any horizontal text margins.
-Widget graphics tips and tricks
+
-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. +
Figure 4. Example sizes and margins for
+minWidth/minHeight calculations. We chose 144dp as an example good minimum
+width for the text labels.
Example calculations are below:
-
-
-
- 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. - -
- To reduce banding when exporting a widget, apply the following Photoshop Add -Noise setting to your graphic. - -
- Apply 9-patch techniques to shrink the graphic and set the padding of the -content area. (See -the detailed guide here.) - -
- 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
XML:. This -technique references the original artwork, in this case -"background.9.png", and instructs the device to dither it as -needed.
-
+ minWidth= 144dp + (2 × 8dp) + (2 × 56dp) = + 272dp
+ minHeight= 48dp + (2 × 4dp) = 56dp
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.)
- -
Note: 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.
- -Widget graphics file format
- -Save your widget artwork using the appropriate bounding box size in PNG-24 -format on a transparent background and in 8-bit color.
- -
If there is any inherent content padding in your widget background nine-patch, you should add to
+minWidth and minHeight accordingly.
Resizable widgets
+ +Widgets can be resized horizontally and/or vertically as of Android 3.1, meaning that
+minWidth and minHeight effectively become the default size for
+the widget. You can specify the minimum widget size using minResizeWidth and
+minResizeHeight; these values should specify the size below which the widget would be
+illegible or otherwise unusable.
This is generally a preferred feature for collection widgets such as those based on {@link +android.widget.ListView} or {@link android.widget.GridView}.
+Adding margins to your app widget
+ +As previously mentioned, Android 4.0 will automatically add small, standard margins to each edge
+of widgets on the Home screen, for applications that specify a targetSdkVersion of 14
+or greater. This helps to visually balance the Home screen, and thus we recommend that you
+do not add any extra margins outside of your app widget's background shape in Android
+4.0.
It's easy to write a single layout that has custom margins applied for earlier versions of the +platform, and has no extra margins for Android 4.0 and greater. See Adding Margins to App Widgets +in the Developer's Guide for information on how to achieve this with layout XML.
+ + +Designing Widget Layouts and Background Graphics
+ +Most widgets will have a solid background rectangle or rounded rectangle shape. It is a best +practice to define this shape using nine patches; one for each screen density (see Supporting Multiple Screens for details). +Nine-patches can be created with the draw9patch tool, or simply with a +graphics editing program such as Adobe® Photoshop. This will allow the widget background shape +to take up the entire available space. The nine-patch should be edge-to-edge with no transparent +pixels providing extra margins, save for perhaps a few border pixels for subtle +drop shadows or other subtle effects.
+ +Note: Just like with controls in activities, you should ensure +that interactive controls have distinct visual focused and pressed states using state list +drawables.
+ + +
+
+Figure 5. Nine-patch border pixels indicating stretchable +regions and content padding.
+ + +Some app widgets, such as those using a {@link android.widget.StackView}, have a transparent +background. For this case, each individual item in the StackView should use a nine-patch background +that is edge-to-edge with little or no border transparent pixels for margins.
+ +For the contents of the widget, you should use flexible layouts such as {@link +android.widget.RelativeLayout}, {@link android.widget.LinearLayout}, or {@link +android.widget.FrameLayout}. Just as your activity layouts must adapt to different physical screen +sizes, widget layouts must adapt to different Home screen grid cell sizes.
+ +Below is an example layout that a music widget showing text information and two buttons can use. +It builds upon the previous discussion of adding margins depending on OS version.
+ ++<FrameLayout + android:layout_width="match_parent" + android:layout_height="match_parent" + android:layout_margin="@dimen/widget_margin"> + + <LinearLayout + android:layout_width="match_parent" + android:layout_height="match_parent" + android:orientation="horizontal" + android:background="@drawable/my_widget_background"> + + <TextView + android:id="@+id/song_info" + android:layout_width="0dp" + android:layout_height="match_parent" + android:layout_weight="1" /> + + <Button + android:id="@+id/play_button" + android:layout_width="@dimen/my_button_width" + android:layout_height="match_parent" /> + + <Button + android:id="@+id/skip_button" + android:layout_width="@dimen/my_button_width" + android:layout_height="match_parent" /> + </LinearLayout> +</FrameLayout> ++ +
If you now take a look at the example music widget from the previous section, you can begin to +use flexible layouts attributes like so:
+ + +
+
+Figure 6. Excerpt flexible layouts and attributes.
+ + +When a user adds the widget to their home screen, on an example Android 4.0 device where each +grid cell is 80dp × 100dp in size and 16dp of margins are automatically applied on all sizes, +the widget will be stretched, like so:
+ + +
+
+Figure 7. Music widget sitting on an example 80dp x 100dp +grid with 16dp of automatic margins added by the system.
+ + +Using the App Widget Templates Pack
+ +When starting to design a new widget, or updating an existing widget, it's a good idea to first +look at the widget design templates below. The downloadable package below includes nine-patch +background graphics, XML, and source Adobe® Photoshop files for multiple screen densities, OS +version widget styles, and widget colors. The template package also contains graphics useful for +making your entire widget or parts of your widget (e.g. buttons) interactive.
+ + +
+
+Figure 8. Excerpts from the App Widget Templates Pack +(medium-density, dark, Android 4.0/previous styles, default/focused/pressed states).
+ + +You can obtain the latest App Widget Templates Pack archive using the link below:
+ ++ Download the App Widget Templates Pack for Android 4.0 »
+ diff --git a/docs/html/guide/topics/appwidgets/index.jd b/docs/html/guide/topics/appwidgets/index.jd index 78b5b511b6033..22283cdc306b3 100644 --- a/docs/html/guide/topics/appwidgets/index.jd +++ b/docs/html/guide/topics/appwidgets/index.jd @@ -327,6 +327,49 @@ following layout classes:Descendants of these classes are not supported.
+Adding margins to App Widgets
+ +Widgets should not generally extend to screen edges and should not visually be flush with other widgets, so you should add margins on all sides around your widget frame.
+ +As of Android 4.0, app widgets are automatically given padding between the widget frame and the app widget's bounding box to provide better alignment with other widgets and icons on the user's home screen. To take advantage of this strongly recommended behavior, set your application's targetSdkVersion to 14 or greater.
+ +It's easy to write a single layout that has custom margins applied for earlier versions of the platform, and has no extra margins for Android 4.0 and greater:
+ +-
+
- Set your application's
targetSdkVersionto 14 or greater.
+ - Create a layout such as the one below, that references a dimension resource for its margins:
+
+
+<FrameLayout + android:layout_width="match_parent" + android:layout_height="match_parent" + android:layout_margin="@dimen/widget_margin"> + + <LinearLayout + android:layout_width="match_parent" + android:layout_height="match_parent" + android:orientation="horizontal" + android:background="@drawable/my_widget_background"> + … + </LinearLayout> + +</FrameLayout> +
+ +
+ - Create two dimensions resources, one in
res/values/to provide the pre-Android 4.0 custom margins, and one inres/values-v14/to provide no extra padding for Android 4.0 widgets: + +res/values/dimens.xml:
+<dimen name="widget_margin">15dp</dimen>
+ +res/values-v14/dimens.xml:
+<dimen name="widget_margin">0dp</dimen>
+
+
Another option is to simply build extra margins into your nine-patch background assets by default, and provide different nine-patches with no margins for API level 14 or later.
+ +