Develop Reference

High resolution app backgrounds?

and i would like to have a nice high resolution background for it.
If i mind galaxy S4 and galaxy Note3, they have 1080 x 1920 px screens.
That means my 1080 x 1920 px background will be 3 MB.
What!?? Yes. My whole app should be 3 MB not only one drawable piece.
So my question is, how developers solve this? I would like to have a nice textured well designed background, if it would be flat design, there wouldnt be problems like this.
And okay.. lets say Galaxy S4 and Note3 have really big amount of memory and fast processor and i use that 3MB background, but... what happens when somebody would like to use my app with a low budget device? Maybe its cannot even show that big image.
Any ideas about this?

If you are worried about other devices you should simply define different resources along with the correct size qualifiers, like stated in the Android guidelines.
smallestWidth sw<N>dp
Examples: sw600dp sw720dp
The fundamental size of a screen, as
indicated by the shortest dimension of the available screen area.
Specifically, the device's smallestWidth is the shortest of the
screen's available height and width (you may also think of it as the
"smallest possible width" for the screen). You can use this qualifier
to ensure that, regardless of the screen's current orientation, your
application's has at least <N> dps of width available for it UI.
...
Basically you can define a drawable-sw<N>dp for each family of screens you want to support, putting in there targeted pictures as you need.

I think you need to change the resolution of your image. I created a 1024 x 768 PNG background image and its size was only around 300kb.
Check your image resolution. I recommend 72 pixels/inch. I'm not sure if there's any other softwares, but you can check and change your resolution on Adobe Photoshop if you go to Image -> Image Size. You might need to uncheck 'Resample Image' I think.

Android Screen Sizes for different devices

I am new to android development and now i have started developing wallpaper apps.I saw the android developer page which tells the ratio 3:4:6 or something which i don't understand. Everything is working but the image which i set go off the screen sometimes it gets cropped around the corners and image does not look good. i use the screen size 600*480 in hdpi. Any suggestion about the different size images i should use may be for ldpi,mdpi,hdpi, xhdpi.I want my wallpaper look good in home screens of both tablets and for large size screen mobiles.
Thank You.

3:4:6:8 , so if you have 600*480 in hdpi then it should go like this
3k:300*240
4k:400*320
6k:600*480
8k:800*640
but since there are multiple device with same dp but different screen size, you can never quitly fit for every device

Android layout multiple screen

Sorry but i cant understand how i can draw a right picture for the right android phone size.
I readed the android documentation, and they say for i just think in screen size and density and not in resolution, so what size should have my picture?
For example,if i have a phone with size 1000x400(stupid example),and want a button(40x40) that will be in middle,what size should i do?? 40x40?? But in documention they say for dont look for resolution :\
Im confuse...
ps: The documention link Android multiple screens

Basically you'll have to realize that although resolution, screen size and screen density are separate attributes, they are still somewhat related. If your button is 40x40 as you mentioned, and that's the size you find looks good in the center on a hdpi(high density) device, you will have to scale it so that it fits accordingly on mdpi(medium density) and xhdpi(extra high density) devices. What I like to do is use PhotoShop or another graphical editor and resize my assets so that they fit on whatever density devices I'm trying to target. I make sure to always use *WRAP_CONTENT* for my height and width attributes and never fixed values.
Also, if you do not include these scaled alternatives in your res/drawable folders..you're basically saying that you're relying on the system to scale them for you, which can be a gamble. So I always go with resizing my assets so that I include a version for all densities. The link you posed explains everything pretty well

Bitmap scaling to fit different screen size/density

I do not really understand all those things about pixel density and device independant pixels and I want to know if I should worry about this.
More specifically, here is how my application work right now:
For the “layout screens”, I’m using RelativeLayout or LinearLayout and I never use pixels or dp, so I guess that this will look good on every device
For the main game screen, there is only a SurfaceView on the screen. With the values given by onSurfaceCreated() (pixels or dp? I don’t know), I compute the size and position of every element of the game, then I load the Bitmaps (with BitmapFactory.decodeResource() and then Bitmap.createScaledBitmap()) and put them on the screen with drawBitmap()
I tested on my phone (480 × 800 hdpi) and on the emulator (240 × 320 mdpi), and both looks good.
My questions are:
Is this the right thing to do? I do not understand how (and why) I could use the fact that some devices are hdpi and others are mdpi.
Should I provide different bitmaps for different screen densities, and why? (right now I have everything in res/drawable-hdpi)
What size should my .png have? Can I create them much bigger (2 ×) than their expected size, in order to be sure that this will not look blur or aliased?

My knowledge about this is limited, as i never developed games.. as i supposed you are doing.
Is this the right thing to do? I do
not understand how (and why) I could
use the fact that some devices are
hdpi and others are mdpi.
With this information you can load different images automatically. You can you the directories:
drawable-hdpi
drawables-mdpi
...
Should I provide different bitmaps for
different screen densities, and why?
(right now I have everything in
res/drawable-hdpi)
If you have all in hdpi then the images will be shrinked i think, to be smaller due to the lack of specific images o that scale. Providing the images will give you more control over the final product and it will spend less processing.
What size should my .png have? Can I
create them much bigger (2 ×) than
their expected size, in order to be
sure that this will not look blur or
aliased?
I think they can be exactly the size needed. But as i said above.. not much experience.

Android: Should my graphics by 480x800 or 480x854?

I'm wanting to target WVGA (480x800) and FWVGA (480x854) devices with my program. My question is: for my full screen background bitmaps which resolution should I make them?

There are a few ways you can attack this issue.
Make one background per aspect ratio and calculate which to use when the app starts. Find the aspect ratio by dividing the width by the height.
Make one background with filler on the sides and bottom for cropping, when you display the image resize it's dimension which has the largest difference from that of the screen's resolution to the exact screen resolution. This will cause the bottom or sides to get cropped a bit.
You could also use a combination of these strategies to create a couple backgrounds, one each for a range of aspect ratios, and then use the cropping strategy to take up the negligible difference.

Be flexible. Android can be run on many different devices, and it would be a very bad idea to limit yourself to certain resolutions. Instead, write your code so that it scales. (Keep it mind that you might have to crop the image if necessary, or live with different aspect ratios).
Just as food for thought... there are Android devices with 480x320, 240x320, 480x800, 480x854, not the mention the upcoming Samsung tablet at a higher resolution. Limiting yourself to a certain resolution would be bad.
Here is something from the SDK you may want to read up on too: http://developer.android.com/guide/practices/screens_support.html
EDIT: Assuming that you're focusing on those two resolutions -- I would say it depends on your image. Your best bet may be to go for 480x854 and design the image in such a way that it won't look bad if you lose 27 bytes on either side. If that's impossible, make it 480x800 and add black bars on either side if run on 480x854.

you can get any bitmap and convert it into a drawable using BitmapDrawable .Then you can set bounds to the drawable to match your screen background.

I've made my background graphics 480x864, the hdpi equivalent of WQVGA and thus as large as it gets. Since I center background graphics vertically, this will display nicely on QVGA, HVGA, WQVGA and WVGA, cropping a bit in most cases. To make sure that the important elements are always seen, I limit them to an area of 480x640 in the center.
To leave nothing to chance, I provide scaled down versions of the graphics at the same aspect ratio for MDPI and LDPI. Works great so far.