The support library provides support for older Android versions by backporting new features and components. It includes libraries for app compatibility, fragments, cardview, recyclerview and more. The support library works by including shims that check the Android version and use the native implementation where available, or a support version as needed. It is important to use consistent support library versions and follow best practices around configuration, versioning and compatibility. The support library continues to be updated regularly with new features, bug fixes and improvements to support developers.

1. The support you need
Shahar Barsheshet

2. About me
Shahar Barsheshet
shahar2k5

3. Talk agenda
● Intro to Support library
● How it works?
● Why should I use it?
● New cool features

4. Do you need
support ???

5. The beginning
The Android support library was first release at 2011, bringing
support to thousands of devices, old as new.
The Goal: new API for old Android version
Starting with the famous v4.

6. Support Libraries
What’s inside?
palette
cardview
gridlayout
leanback
recycleview
mediarouter
appcompat
support-v4
multidex renderscript annotations

7. What’s inside?
ComponentsCompatibility
RecyclerView
CardView
ViewPager
etc.
Fragment
Loaders
AppCompat
etc.

8. The Present
● New features
● Fast Releases
● Bug fixes
● Respond to developers needs
# Design
# Leanback
# Wear
# Percent
# Preferences
# UI
# Utils

9. How it works?

10. How it works?
Intent myServiceIntent = new Intent();
ContextCompat.startForegroundService(this, myServiceIntent);
package android.support.v4.content;
public static void startForegroundService(Context context, Intent intent) {
if (Build.VERSION.SDK_INT >= 26) {
context.startForegroundService(intent);
} else {
// Pre-O behavior.
context.startService(intent);
}
}

11. How it works?
Shims… That’s it?
Well… not quite...

12. How it works?
Fragments

13. How it works?
Fragments
IllegalStateException: Can not perform this
action after onSaveInstanceState
Calling FragmentTransaction#commit() after Activity’s onSaveInstanceState()

14. How it works?
Fragments
● Extra cautious when committing transaction in Activity’s lifecycle callbacks!
● Avoid committing in Asynchronous callbacks!
● Use commitAllowingStateLoss() only as a last resort!
Revision 24.0.0 - Added Fragment.commitNow() for synchronous commit.
Revision 25.1.1 - FragmentTransaction.setAllowOptimization(true)
Revision 25.4.0 - Transactions are not allowed during state change.
Revision 26.0.0 - setAllowOptimization(true):deprecated , isStateSaved():added.

15. Versioning…?
Remove a fragment from backstack and start a new Activity
Ref: https://issuetracker.google.com/issues/37129908

16. AppCompat
Support library gives us the option to use the same
theme for devices with support for Material Design
even below API 21.
This means that we can customize one theme to
match almost all API levels.
In addition, we get to use some nice components
that were added in API 21,
like the Floating Action Button, Toolbar,
DrawerLayout and more, out-of-the-box.

17. AppCompat
<resources>
<color name="primary">#3F51B5</color>
<color name="primary_dark">#303F9F</color>
<color name="accent">#FF4081</color>
</resources>
<resources>
<!-- Base application theme. -->
<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
<!-- Customize your theme here. -->
<item name="android:colorPrimary">@color/primary</item>
<item name="android:colorPrimaryDark">@color/primary_dark</item>
<item name="android:colorAccent">@color/accent</item>
</style>
</resources>
style.xml
colors.xml

18. Material Design
<item name="colorPrimary">@color/primary</item>
<item name="android:colorPrimary">@color/primary</item>
!=
minSdkVersion="21"

19. Whats new?
public class CustomFontTextView extends TextView {
private void applyCustomFont(Context context) {
Typeface customFont = FontCache.getTypeface("SourceSansPro-Regular.ttf", context);
setTypeface(customFont);
}
}

20. Whats new?
Downloadable fonts
dependencies {
…
compile "com.android.support:support-compat:26.0.1"
}

21. Whats new?
Downloadable fonts
● Shrink APK size
● Google fonts catalog - over 800 free fonts
● Android Studio integration
● Font caching across multiple apps

22. Whats new?
public class ResizableTextView extends TextView {
private void setText(String text) {
// measure width and height
// calculate text size to fit in view
}
}

23. Whats new?

24. Whats new?

25. Whats new?
EmojiCompat
● Downloadable fonts
● Bundled fonts in the project
dependencies {
…
compile "com.android.support:support-emoji:26.0.1"
}

26. Whats new?
EmojiCompat - How it works

27. Whats new?
EmojiCompat
<android.support.text.emoji.widget.EmojiTextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
<android.support.text.emoji.widget.EmojiEditText
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
<android.support.text.emoji.widget.EmojiButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>

28. Versioning…?

29. Versioning…?
compile 'com.android.support:appcompat-v7:26.0.2'
compile 'com.android.support:support-v4:26.0.2'
compile 'com.android.support:cardview-v7:26.0.2'
compile 'com.android.support:design:26.0.2'

30. Versioning…?
groupId: com.android.support
artifactId: support-v4
version: 26.0.2
Gradle Dependencies
compile 'com.android.support:support-v4:26.0.2'
Maven

31. Versioning…?
compile 'com.android.support:support-v4:26.0.2'
Minimum supported API level
compile 'com.android.support:support-v4:26.0.2'
The library version - codebase wise

32. Versioning…?
android {
compileSdkVersion 26
}
dependencies {
compile "com.android.support:appcompat-v7:26.0.1"
}
Support Library revision should be the same as the compiled sdk version

33. Versioning…?
compile 'com.android.support:appcompat-v7:25.+'
DON’T!
compile 'com.android.support:appcompat-v7:26.0.1'
compile 'com.android.support:design:25.0.1'
compile 'com.android.support:design:25.3.1'
DON’T!
WARNING!

34. Versioning…?
ext {
supportLibVersion = '26.0.2'
}
dependencies {
compile "com.android.support:appcompat-v7:${supportLibVersion}"
compile "com.android.support:design:${supportLibVersion}"
compile "com.android.support:support-annotations:${supportLibVersion}"
compile "com.android.support:support-vector-drawable:${supportLibVersion}"
compile "com.android.support:animated-vector-drawable:${supportLibVersion}"
}
TIP! Make your life easier, use a variable for the version

35. Versioning…?
Revision 26 -> min sdk v14
allprojects {
repositories {
maven { url "https://maven.google.com" }
}
}

36. When?
When?
1. Targeting latest version but supporting older
versions with the same API’s.
2. Some components are only exists in the
Support Libraries.

37. When?
When?
Well… Always…

38. Android, support me!
To sum it all up
● Use the support libraries!
● Do it right!
● Don’t re-invent the wheel
● Understand what you are doing (or at least try to)
● Bugs - don’t afraid to open!

39. ?
Questions

40. Thanks!
By the way
We are hiring!Shahar Barsheshet