Android App Development 08 : Support Multiple Devices
1. 8
Support
Different Devices
Anuchit Chalothorn
anoochit@gmail.com
Licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.
2. Supporting Different Languages
Android will run on many devices in many
regions. To reach the most users, your
application should handle text, audio files,
numbers, currency, and graphics in ways
appropriate to the locales where your
application will be used.
3. Using Resources for Localization
The default resource set must also include any
default drawables and layouts, and can include
other types of resources such as animations.
● res/drawable/
● res/layout/
● res/anim/
● res/xml/
● res/raw/
4. Language String
Android makes this easy with a resources
directory in each Android project. Within the
res/ directory are subdirectories for various
resource types. There are also a few default
files such as res/values/strings.xml, which
holds your string values.
5. Locale Directories and String Files
To add support for more languages, create
additional values directories inside res/ that
include a hyphen and the ISO country code at
the end of the directory name. eg: values-es
for Spanish, values-th for Thai, values for
English etc.
6. Locale : English
English (default locale), /values/strings.xml :
<?xml version="1.0" encoding="utf-8"?>
<resources>
<string name="title">My Application</string>
<string name="hello_world">Hello World!</string>
</resources>
8. Locale : French
French, /values-fr/strings.xml :
<?xml version="1.0" encoding="utf-8"?>
<resources>
<string name="title">Mon Application</string>
<string name="hello_world">Bonjour le monde !</string>
</resources>
9. Use the String Resources
You can refer to a string resource with the
syntax R.string.<string_name>. There are a
variety of methods that accept a string resource
this way.
10. Use the String Resources
// Get a string resource from your app's Resources
String hello = getResources().getString(R.string.
hello_world);
// Or supply a string resource to a method that requires a
string
TextView textView = new TextView(this);
textView.setText(R.string.hello_world);
11. Use the String in XML
In other XML files, you can refer to a string
resource with the syntax
@string/<string_name> whenever the XML
attribute accepts a string value.
12. Use the String in XML
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/hello_world" />
13. Workshop: Locale
Create form UI like following and make locale
string for English, Vietnamese, Japanese and
Thai.
14.
15. Locale your graphic
You can use qualifiers with any resources
include graphic in drawable directory, eg :
● /drawable for English (default locale)
● /drawable-th for Thai
● /drawable-vn for Vietnamese
● /drawable-ja for Japanese
16. Workshop: Locale your graphic
Create a UI like following and make locale
graphic for English, Vietnamese, Japanese and
Thai.
17.
18. Supporting Different Screens
Android categorizes device screens using two
general properties: size and density. You
should expect that your app will be installed on
devices with screens that range in both size
and density.
19. Sizes and Densities
To declare different layouts and bitmaps you'd
like to use for different screens, you must place
these alternative resources in separate
directories, similar to how you do for different
language strings.
20. Create Different Layouts
To optimize your user experience on different
screen sizes, you should create a unique layout
XML file for each screen size you want to
support.
21. Create Different Layouts
The directory named with a -<screen_size>
suffix.
● /res/layout/main.xml <-- normal
● /res/layout-land/main.xml <-- landscape
● /res/layout-large/main.xml <-- for large
● /res/layout-large-land/main.xml <-- large landscape
22. Create Different Bitmaps
You should always provide bitmap resources
that are properly scaled to each of the
generalized density buckets: low, medium, high
and extra-high density. This helps you achieve
good graphical quality and performance on all
screen densities.
23. Create Different Bitmaps
To generate these images, you should start
with your raw resource in vector format and
generate the images for each density using the
following size scale:
● xhdpi: 2.0
● hdpi: 1.5
● mdpi: 1.0 (baseline)
● ldpi: 0.75
Ref: http://developer.android.com/design/style/iconography.html
26. Supporting Different Platform Versions
While the latest versions of Android often
provide great APIs for your app, you should
continue to support older versions of Android
until more devices get updated.
27. Specify Minimum and Target API
The AndroidManifest.xml file describes details
about your app and identifies which versions of
Android it supports. Specifically, the
minSdkVersion and targetSdkVersion with
<use-sdk element.
28. Specify Minimum and Target API
<manifest xmlns:android="http://schemas.android.
com/apk/res/android" ... >
<uses-sdk android:minSdkVersion="4"
android:targetSdkVersion="15" />
...
</manifest>
29. Check System Version at Runtime
Android provides a unique code for each
platform version in the Build constants class.
Use these codes within your app to build
conditions that ensure the code that depends
on higher API levels is executed only when
those APIs are available on the system.
30. Check System Version at Runtime
private void setUpActionBar() {
// Make sure we're running on Honeycomb or higher to use
ActionBar APIs
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.
HONEYCOMB)
{
ActionBar actionBar = getActionBar();
actionBar.setDisplayHomeAsUpEnabled(true);
}
}
31. Use Platform Styles and Themes
Android provides user experience themes that
give apps the look and feel of the underlying
operating system. These themes can be
applied to your app within the manifest file.
32. Platform Styles and Themes
To make your activity look like a dialog box:
<activity android:theme="@android:style/Theme.Dialog">
33. Platform Styles and Themes
To make your activity have a transparent
background:To make your activity have a
transparent background:
<activity
android:theme="@android:style/Theme.Translucent">
34. Platform Styles and Themes
To apply your own custom theme defined in
/res/values/styles.xml:
<activity android:theme="@style/CustomTheme">
35. Platform Styles and Themes
To apply a theme to your entire app (all
activities), add the android:theme attribute to
the <application> element:
<application android:theme="@style/CustomTheme">
