Best practices to use when targeting multiple screen resolutions on Android

Question

When designing an UI, we need to target many android mutations and various screen resolutions.

• How to differentiate layout for 480 * 800 and 480 * 854 screen resolutions in android?
• how to layout support for various screen in android?

Both questions above recommend to use different Layout code for different screens. Is it really necessary?

• http://developer.android.com/guide/practices/screens_support.html

recommends to

Provide different layouts for different screen sizes

Provide different bitmap drawables for different screen densities

But I still think, we can support multiple screens without creating standalone layout for each screen resolution. Or am I wrong?

I know, and I do use, 9-patch for scalable background images (or form inputs, and so on)
and I do use dp (density pixel) to declare sizes relatively to screen density

But what are next best practices ?

Answer 1

I think the answer to this has changed recently, but I'll go over historical solutions.

Pre-Honeycomb, the solution was to create a dynamic layout that could adjust itself to the size of the screen (using 9-patches, dips, layouts that expand/shrink, etc.). This meant that none of your Views could be "pixel perfect", but you could adjust to different aspect ratios that you encounter. Sometimes you would come up with different layouts for landscape and portrait, but beyond that customization wasn't necessary.

With the release of Honeycomb, the problem got a lot more complex. Now you've got dramatically different screen sizes, where your app stretching doesn't look good at all. You've got tablets that stretch from 7" to 10" - which one is "large" vs. "xlarge"? 3.0 and 3.1 were an awkward period, where you had to detect the API version/screen size and configure your app accordingly (supposing your app supports both phones and tablets).

However, everything's changed in 3.2 and beyond. Now, the best practice can be described thus: think like a web designer, not an Android designer . Instead of thinking about phone vs. tablet vs. landscape vs. portrait layouts, think instead of layouts that work on particular screen sizes.

This thought process is detailed by this blog post , and these slides , but I think it's best demonstrated by going to some sample web pages and seeing it in action. Try visiting this page (or this page , or this page ) and changing the size of your browser. Notice how they dynamically change layout based on the width - this is what you want in Android as well.

So now you've got a layout that works between screen width 150dp and 400dp; another one that works between 401dp and 800dp; a third that handles 800dp and 1000dp, etc. This way of thinking does not end up with you, as a developer, doing too much more work than before - instead of defining a phone layout, a tablet layout (each with a portrait/landscape layout), you just define a few layouts that work with different widths.

Right now we're in an awkward transitional stage as most people don't have devices that support this practice. So "best practice" is essentially all of the above. In a few years, when everyone's got ICS and beyond, then we can all breath a sigh of relief.

(I apologize if you were looking for specific solutions; this answer ended up being relatively theoretical rather than having concrete answers, mostly because I felt the question was pretty open-ended. If you've got a specific problem you want to solve, I can try to address that elsewhere.)

Answer 2

If you build your views using "dp" it would, basically, be the same size for eack screen size.
In most cases you will prefer that your view will resize itself proportional to the screen size.
Of course, in most cases you will need to build separate layouts for tablets.
But, besides I can recommend you to do the next steps:

1. Add this library to your project.

2. Now in your layout you can write views like that:

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="I'm scalable!" 
    android:textSize="@dimen/_12sdp"/>

In this example your TextView will scale on each screen size.

Answer 3

These are some suggestions, in random order:

• Avoid AbsoluteLayout , I know that it is deprecated, but you can still use it; forget it and use LinearLayout and RelativeLayout instead
• Use 9-patch to create buttons and backgrounds, so that they will appear the same for each resolution
• Use DisplayMetrics() to get informations about the screen, to show different things in different screens (ie to show AdMob "Banner" in smartphones and AdMob "Leaderboard" in tablets)
• Create WVGA layout first (this is only a personal opinion, but I've found it a nice way of working): as far as I know the most smartphones are WVGA or at least HVGA (QVGA is not so frequent), so creating a perfect WVGA layout will make you able to satisfy lots of phones, than you can create a different layout for lpdi-screen and tablets (that are a market-share minority too, at the moment)

In conclusion I recommend you to create a layout for phones and on for tablets, that can adjust itself to screen resolution: this will fit the most devices; for borderline devices (ie 7" tablets or 5.3" phone) I'd work with different drawables/different XML layouts.

Answer 4

I would suggest as much as possible use Relative calculations rather than Absolute. Avoid Hard coding of numbers for padding, margins etc. Simply give them a value in relation to desired property like Width, height of screen or any component.