MTC 2013 Berlin - Best Practices for Multi Devices

Hasan Hosgel | ImmobilienScout24

Best Practices to develop the Layouts for different Android Device Classifications

About Me Hasan Hosgel •  developer @

ImmobilienScout24,

•  CO-Organizer @ GDG Berlin Android

•  Twitter / Github: alosdev

•  Google+: Hasan Hosgel

> 3600 Android Devices

Source: http://www.flickr.com/photos/hertenberger/1434191066/

Device Classification

Images sources: https://play.google.com/store/devices

Images sources: https://play.google.com/store/devices http://www.htc.com/de/

Images sources: http://www.sony.de/hub/google-tv

Images Sources https://developer.ford.com/

Images sources: http://www.sonymobile.com/global-en/products/accessories/smartwatch-2-sw2/

Source: http://www.flickr.com/photos/paulbrigham/8452522044/

Resource Folders You can use several qualifiers in the resource folders name for serving the best matching resource.

Qualifiers •  Language (-en) •  Language & Region (-en-rUS) •  Smallest Width (sw600dp) •  Screensize (-small, -normal, -large) •  Screen Orientation (-port, -land) •  Screen Pixel Densitiy (-mdpi, -hdpi,...) •  Platform Version (-v11, -v13)

Best Matching Resources Win 1.  res/values/strings.xml 2.  res/values-en-rUS/strings.xml 3.  res/values-large/strings.xml 4.  res/values-sw600dp/strings.xml

The order of the qualifiers in the previous slides gives the ranking, if two resources have the same matching number of qualifiers.

Images Resources •  Use the different qualifiers for the screen pixel

density (mdpi, hdpi, etc.) •  If you are forced to use text on images use

language and region (en, es-rUS, en-rUS, etc.) •  Better approach is to use 9-patch drawables, which

stretches automatically depending on the content inside.

•  You must provide different launcher icons for Froyo, Honeycomb and above? Use the platform version. (v4, v11, v14)

Classifications for Layouts

Platform version at least v13

project-folder/res/

layout/ è small phones

layout-sw320dp/ è other phones

layout-sw600dp/ è tablets 7”


Platform version at lower v11 project-folder/res/

layout/ è phones

layout-v11/ è tablets 10” layout-v13/ è small phones

layout-sw320dp/ è other phones



hint The smallest width qualifier gets automatically platform version "-v13" through the packager, for avoiding problems with the number of matching qualifiers.

Howto Classify In Code •  Read configuration from the device •  Smarter approach use boolean

resources

project-folder/res/values/layouts.xml

<resources>

<bool name="is_phone_small">false</bool>

<bool name="is_phone_other">true</bool>

<bool name="is_tablet_7">false</bool>


</resources>


<resources>





</resources>


<resources>





</resources>


<resources>





</resources>


<resources>





</resources>

Usage in code:

getResources().getBoolean(R.bool.is_phone_small)


<resources>





</resources>

Usage in code:

getResources().getBoolean(R.bool.is_phone_small)

Current File Structure project-folder/res/

layout/main.xml

layout-v11/main.xml

layout-v13/main.xml

layout-sw320dp/main.xml



Fixing one bug in the 10" layout has to be done in two files


è error prone


è error prone

How to avoid this?


è error prone

How to avoid this? - Use resource aliasing.

Resource Alias

Put your layout files in the default folder.

project-folder/res/

layout/main_phone_small.xml

layout/main_phone_other.xml

layout/main_tablet_7.xml

layout/main_tablet_10.xml

Resource Alias

2.  Create an item with the needed classification in the previously defined values folder.

project-folder/res/values-sw720dp/

layouts.xml

<item name="main"

type="layout">@layout/main_tablet10</item>

Resource Alias



layouts.xml

<item name="main"


Resource Alias



layouts.xml

<item name="main"


Resource Alias



layouts.xml

<item name="main"


CODE

Sample Screen

Sample Screen

Sample Screen

Use <includes>

Usage Includes <LinearLayout … > …

<include layout="@layout/footer"/>

…

</LinearLayout>


<include layout="@layout/footer"/> …

</LinearLayout>


<include layout="@layout/footer"/> …

</LinearLayout>

CODE

Sample Screen

Use <includes>

Sample Screen

Use <includes>

Sample Screen

Use <includes>

Create custom view

Custom View public class CustomView extends LinearLayout { … public CustomView(Context context, AttributeSet attrs) { … addView(createTextView(context, "label"), lp); addView(createTextView(context, "desc"), lp); if(getResources().getBoolean(R.bool.is_phone)){ setOrientation(VERTICAL); } else { setOrientation(HORIZONTAL); } } … }

Sample Screen

Use <includes>

Create custom view

Sample Screen

Use <includes>

Create custom view

If custom view has much more business logic and need lifecycles Create a Fragment

Custom XML Attribute <resources> <declare-styleable name="CustomView"> <attr name="label" format="reference|string" /> <attr name="value" format="reference|string" /> <attr name="orientation" format="enum"> <enum name="horizontal" value="0" /> <enum name="vertical" value="1" /> </attr> </declare-styleable> <resources>






1.  Add to root XML node xmlns:app="http://schemas.android.com/apk/res-auto" 2.  Usage in custom view <de.alosdev.CustomView android:id="@+id/customView" android:layout_width="wrap_content" android:layout_height="wrap_content" app:label="label 1" app:orientation="vertical" app:value="value 1" />

public class CustomView extends LinearLayout { static final int[] ORIENTATION = new int[] { HORIZONTAL, VERTICAL }; public CustomView(Context context, AttributeSet attrs) { super(context, attrs); … TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.CustomView); try { setOrientation(ORIENTATION[ a.getInt(R.styleable.CustomView_orientation, 0)]); } finally { a.recycle(); } } … }




CODE

Custom XML Attribute

Best Practices •  You have already an application

» Remove orientation fixation and suppressing of orientation change from manifest to avoid long bug analyzing.

•  You start from the scratch »  Focus on main classification for faster time

to market » But create an overall concept for better

modularization

Best Practices •  If you support both orientations, save

the instance state while orientation changes for more responsiveness » Especially for states, that need a long

computation for creation. » Make the state object Parcelable for

faster write & read and also to have a smaller memory footprint

Developer Hints •  You can start an activity for result from

a fragment, so the response can be handled in the fragment.

•  If you want to register a special service on every onCreate method of an activity give the ActivityLivecycleCallbacks a try. You can register them in the onCreate method of the application. (min v14)

•  If you get a BadParcelableException with the cause ClassNotFound-Exception, the source can be a NullPointerException during the read or write of the Parcelable. Exceptions are hidden during the parcel process.

Listener Hell If you have to many listeners or you think the programming model is old school like the “goto statements”. Give message/ event/ service bus a try. For Android: •  Otto from Square •  EventBus from greenrobot

See also: Callbacks as our Generations' Go To Statement

Custom Theme & Style Android Ui Utils

ActionBar Style Generator

Holo Color Generator

Q & A

Source: http://www.flickr.com/photos/21496790@N06/5065834411/

www.immobilienscout24.de www.immobilienscout24.de

Thanks for your attention & we are hiring! Contact: Hasan Hosgel Twitter: @alosdev Github: alosdev

Best Practices to develop the Layouts for different Android Device Classifications Repo: https://github.com/alosdev/multidevice-nightmare-demo SlideShare: http://www.slideshare.net/hosgel/mtc-2013-berlin-best-practices-for-multi-devices

Technology

MTC 2013 Berlin - Best Practices for Multi Devices