As per "android multiple screen design":
"As you design your UI for different screen sizes, you'll discover that each design requires a minimum amount of space. So, each generalized screen size above has an associated minimum resolution that's defined by the system. These minimum sizes are in "dp" units—the same units you should use when defining your layouts—which allows the system to avoid worrying about changes in screen density.
xlarge screens are at least 960dp x 720dp
large screens are at least 640dp x 480dp
normal screens are at least 470dp x 320dp
small screens are at least 426dp x 320dp"
DisplayMetrics class gives me access to actual width and height of the screen. However is the above table available programmatically. Or do I need to store these values as constants in my app. The second option seems hacky.
Your problem is that you try to make a fixed design for x known resolutions whereas Android's Framework is based on the idea that you don't know in advance the exact dimensions of the device your app will be running on. And if you look at the Android market, that's a good assumption to make.
If you make good uses of :
-selectors like "sw600dp"(7" tablet)
-nine-patchs (stretchables assets)
-dimensions in dip for things that need to have a fixed size (for example a button needs to be 48dp at least in order to be big enough)
you can make very good designs that adapt to all form factors from 2" phones to 10" tablets.
Related
I've created my app but I decided to test it on all screens to be adaptive. Maybe testing it in
MDPI(160dpi), HDPI(240dpi), XHDPI(320dpi), XXHDPI(480dpi) and XXXHDPI(640dpi) which corresponds to all screen sizes. However I tested my app on two devices support 320dpi. I thought that I get the same result but it don't. so don't know how to test my app on all screens. I'm confused.
I used Genymotion for emulators:
one with 720 * 1280 320dpi
screenshot
and other with 1200 * 1920 320dpiscreenshot
Please help me with that or if there's another way to do it let me know.
thanks in advance
(Bunch of explanation about why this is happening, I put my suggestions in the last section)
DPI isn't the same as size, it's just about how many pixels are packed into a certain area. The higher the DPI, the more pixels there are, meaning they're a lot smaller. So you can get fine detail, but it also means you need more of them to cover a physical distance or area on the screen.
Which is why Android uses dp instead of raw pixel sizes most of the time - the standard minimum touch-target size is 48dp, but how many actual pixels that is depends on the pixel density of the display. For mdpi displays it'll actually be 48 pixels, for xxxhdpi it'll be 4x that amount
It also means if you're doing your design work in dp, the pixel density of the screen doesn't matter - elements with a fixed size will always be broadly the same size on every screen (the mdpi etc buckets are like a "close enough" grouping, the devices in each group won't all have exactly the same DPI) because it's getting translated to the equivalent number of actual pixels. What testing does help with is checking your drawable assets look ok on different screen densities
So you have two devices with the same DPI right?
720 x 1280
1200 x 1920
Because they're the same DPI, those dimensions are converted to dp by the same factor. Let's work it out to be precise (but the exact numbers aren't important): 320 DPI is xhdpi according to that link up there, so 1dp = 2px. Let's convert those screen sizes to dp
360dp x 640dp
600dp x 960dp
It's the same situation but hopefully having those sizes expressed in dp helps you see the problem - when you're designing a layout, you're working with dp, right? The available space you have to work with is defined in dp, and one of those has a whole lot more space than the other! Putting a 300 dp-wide TextView in the layout would almost fill the first one horizontally, but it would only cover half of the second. That's gonna look pretty different!
This is why phones and tablets look so different - even if you have a relatively new phone, and an old Nexus 7 with a much lower resolution, the Nexus 7's screen is going to feel "bigger" and more "spacious". It's a physically larger device, so even though it's low-res, it's also low-density which means those pixels are spread across a larger area. Lower DPI means those pixels translate into more inches. And in the density-independent pixel (dp) system, that means you get way more dp to work with, more space for your layout. Which is what you want on a tablet, you don't want it to look and feel like a massive phone!
That's why it's different - basically one of your devices has more space to work with than the other, because it has more pixels, and the same DPI so those pixels aren't just used for finer detail.
As for testing, you need to look at different screen sizes - which is dependent on the resolution and the DPI. Basically pixels / DPI = size in inches. Do that for your two 320 DPI examples and you'll see one is a fair bit larger, physically, while having the same density
Probably the easiest way to do this, really, is to look at your layout in the design view, and change the Preview Device setting at the top. Some of the Phone devices are more "spacious" than others, newer ones are taller, so go through them and see how your layout changes. Try a Tablet one and see what a lot of extra space does. And if you go down to the Generic Phones and Tablets section at the bottom, there are a bunch of reference devices in there, some of which will be very cramped!
Once you've found a few useful ones, you can set up your emulator / virtual devices with each of their screen resolution / density combinations. I don't know about Genymotion, but the built-in AVD manager gives you a lot of those device definitions as templates when you create a new virtual device. You should at least be able to enter those settings yourself
Also when you publish an app on the Play Store, they'll automatically run it on a bunch of reference devices and give you access to a bunch of screenshots, so you can see if there are any problems with certain screen sizes and fix them before you launch
Ok, so I find generally that everyone will reference the Android Dev when the question is pretaining to background Images in an Android application. All I can find in the the Dev article is:
xlarge screens are at least 960dp x 720dp
large screens are at least 640dp x 480dp
normal screens are at least 470dp x 320dp
small screens are at least 426dp x 320dp
Does that mean I just convert dp tp pixels when I am creating each seperate drawable?
For instance 960dp is 1920px.
You could have any of the next solutions:
really put each image in each density bucket. this will result in better precision of the pixels, but will make your app larger.
put one large image into either drawable-xhdpi or drawable-xxhdpi folders. rest of the densities will automatically adapt.
if the background is simple enough, use either a 9-patch or an xml drawable.
in fact, those solutions are valid for each image you face, and not just backgrounds.
in any case, do remember that having a background for the entire screen takes a lot of memory (can reach 3 MB for just a background, depends on the screen resolution).
I am creating some background images that will cover the "entire" screen of the phone/tablet screen for my app. These images are for the Splash Screen. Basically, my application must support to Phones and Tablets.
I created a huge image which is 2560 x 1600, now time to resize it. But the case is, I am stuck here. What are the screen sizes for mdpi, hdpi, xhdpi, xxhdpi ? These are the screen sizes from phone to tablet right? I need these sizes in pixel values.
I have already visited to the android developer links like supporting multiple screens, but I did not find anything good from them.
Please help me to resize my images by providing the correct screen values in pixels.
Hdpi, xhdpi, etc. are not screen sizes, they are screen pixel densities. If you want to adjust your image according to screen sizes, you should use small/medium/large/xlarge. (And combine it with hdpi/xhdpi/... for sharp and accurate results :))
You can always use some most common resolutions, like HD, fullHD, 800x480 etc. But you have a bigger problem - differences in aspect ratio. Newer devices tend to use 16:9 aspect ratio, but older models with 800x480 screens are different, so you should consider some padding/cropping to ensure image is not stretched, and just then worry about resolution.
Good luck with that :)
Edit:
You can create your own resource folders, you can even use multiple modifiers.
http://developer.android.com/guide/topics/resources/localization.html
Just create folder 'drawable-small-hdpi' or whatever and it will work :)
You can also use other modifiers, f.e. drawable-de-small should load specified drawables only on "german speaking" devices with small displays.
About image sizes: documentation(the article you are linking) states:
xlarge screens are at least 960dp x 720dp
large screens are at least 640dp x 480dp
normal screens are at least 470dp x 320dp
small screens are at least 426dp x 320dp
So you if you want good compatibility, you go like this(in pixels):
small-mdpi = 426x320
small-hdpi = 639x480
small-xhdpi = 852x640
normal-mdpi = 470x320
normal-hdpi = ....
......
xlarge-hpdi = ....
xlarge-xhdpi = 1920x1440
Just remember that 1 dp in mdpi is 1px, in hdpi it is 1.5px, xhdpi is 2px and xxhdpi is 3px.
In practice, you really don't see many xxhdpi devices with small or even normal screen, so you can omit some extremes. If you don't care about some stretching here and there on smaller phones, you can even completely ommit the small option and rely on the match_parent attribute to fit the image.
But you still have to design carefully because these are just minimum sizes.
Also consider phones with hardware buttons and software buttons - with hardware buttons and same screen, you get more space for your app, so, again, different aspect ratio!
From my experience, I would recommend splitting your splash screen in elements that must at all times remail "good looking", like logo. And then define some background that can stretch a bit here and there. So that you can set the background to match_parent and always cover whole screen and "logos" to wrap_content or fixed size in dp so their aspect ratio won't change and pixel size can be easily calculated.
as per android developers docs, 96 X 96 px is the icon size required for high density screens . Can i use the same size icon for all the screens? or I have to provide different sizes for different screens like ldpi, mdpi . Also, png is the only format accepted or any format accepted ?
Also for splash screen, 1440 X 1080 px is for xlarge screens, so can I use this single image for all the other screens (like large, normal and small) Or do i have to provide separate images for all the screens ? Also, what formats are supported?
Please read about how to support multiple screens
xlarge screens are at least 960dp x 720dp
large screens are at least 640dp x 480dp
normal screens are at least 470dp x 320dp
small screens are at least 426dp x 320dp
You have to use separate images and separate layouts to handle different screen sizes. Otherwise for xlarge screens the image may be fine but for small screens it will get cropped. Same will happen with layouts. So for best programming experience please use separate files. Android supports files other than .png as well.
If you use one icon then Android system will stretch and set it for all other resolution. problem is your icon is stretch for large screen. then, it might causes to appearance of the application. so you have to think this.
if you use each icon for each display size, it may causes to apk file size. this is the same thing about other images that adding for different display sizes.so you have to consider this.
most of the time you can manage this with 9patch images to avoid this.
with my experience, I have notice that avoiding images that have circles makes not to use different images for different screen sizes.then you can manage it with less images.When they are stretched circles become ellipse.
I think now you have idea.
I'm implementing an app for Android(API 10). I have few designs for tablet(supposedly) and for mobile phone. Regarding the previous sentence it might sound a bit stupid: in my opinion layouts should be picked according to device's physical size - not resolution, otherwise there might be a phone with high resolution that renders, say, a grid of 5x5, in rather confusing, inadequately small-sized way. In order to provide division by physical size I gotta use /res/layout-* folders. Agreed ?
Also: I'm a bit confused about multiple-screens guide's definition on physical size. Would you mind explaining what physical size is in terms of Android mean, what it's measured in? Is there any correlation with dpi?
Thanks.
A workaround for api level 10 could be something like this:
use the compat lib from the SDK so that you can design with fragments.
Assume everything before android 3 is a phone. For example use your layout files in layout/* for this (and the rest will be based it on unless overriden). This assumption is basically only wrong for the original Samsung Galaxy Tab 7" from 2009.
Assume everything on android 3.x is a tablet (they are), so do some tablet specific layout if you want and have them under layout-v11 (and maybe also layout-v12 if there is anything specific to android 3.1). Tablet specific layout could mean that you arrange your fragments differently and/or show multiple fragments at the same time.
Everything newer (android 3.2+) you can use the new stuff from api level 13. Such as layout-sw600dp/ for some layouts etc etc. http://developer.android.com/guide/practices/screens_support.html#DeclaringTabletLayouts
Physical size is usually measured in inches, it simply tells you the real device's screen size (usually 3-4" inches for phones and 8-11" for tablets).
dpi, is NOT correlated with it. Dpi expresses screen density, how many pixels are shown in a given area (usually a square inch). It could be considered as a measure of screen quality.
Resolution is given by the product of the two; it expresses the total number of physical pixels on a screen.
Going back to your first question, you should be density independent as much as possible; your app should "look the same" on devices with different densities. The /res/layout-* folders are designed to provide this feature, the system scales drawable resources to the appropriate size and you could then declare in your manifest that your app supports any density:
android:anyDensity="true"
On page http://developer.android.com/guide/topics/resources/providing-resources.html#BestMatch you can learn how Android choose the best matching resource.
With Android API 10 the best option for targeting tablets is probably just distinguishing the actual size of the screen in the code using something like:
https://stackoverflow.com/a/5789916/1319155
and then just load a different drawable if the size value returned was greater than 6 (or whatever size you want to declare as a "tablet").
The reason you can't really just use the size folders (i.e. layout/large) is because the folders don't distinguish between phones and tablets very well. A kindle fire and galaxy nexus may both be considered "large" devices.
The reason you can't really use dpi is because that is not a good reflection on what type of device it is, just how "dense" the pixels are on a screen. Most new phones are much denser (having more pixels per inch) than tablets anyway.
There are two ways of doing this. From Android 1.6 (API 4) on, there are four layouts that describe the physical size of the display: small, normal, large, and xlarge. As described on http://developer.android.com/guide/practices/screens_support.html , these correspond to:
xlarge screens are at least 960dp x 720dp
large screens are at least 640dp x 480dp
normal screens are at least 470dp x 320dp
small screens are at least 426dp x 320dp
Note that these are measured in DP, not DPI. DPI is Dots Per Inch, and specifies screen density. DP, also written DIP, are Density-Independent Pixels. Again from the guide:
Density-independent pixel (dp)
A virtual pixel unit that you should use when defining UI layout, to express layout dimensions or position in a density-independent way.
The density-independent pixel is equivalent to one physical pixel on a 160 dpi screen, which is the baseline density assumed by the system for a "medium" density screen. At runtime, the system transparently handles any scaling of the dp units, as necessary, based on the actual density of the screen in use. The conversion of dp units to screen pixels is simple: px = dp * (dpi / 160). For example, on a 240 dpi screen, 1 dp equals 1.5 physical pixels. You should always use dp units when defining your application's UI, to ensure proper display of your UI on screens with different densities.
In other words, 160 DP = 1". Applying this standard, we see:
xlarge screens are at least 6" x 4.5" (7.5" diagonal)
large screens are at least 4" x 3" (5" diagonal)
normal screens are at least 2.9" x 2" (3.5" diagonal)
small screens are at least 2.6" x 2" (3.3" diagonal)
(Not sure why the selection is so odd, but that's what they defined.)
From Android 3.2 on (API 13), there are more options, as described here:
http://developer.android.com/guide/practices/screens_support.html#DeclaringTabletLayouts
Here you can use "smallest screen width," "available width," or "available height" options to define your own categories; again, the unit in question is DP, which is 1/160". Note that these specify the smaller of the two dimensions on the device--e.g., for a 7" tablet they recommend specifying layout-sw600dp, that is, "smallest width 3.75 inches," which would be intermediate between the "large" and "xlarge" sizes defined in API 4. They have a number of specific comments about this topic, including notes about how the widths are measured (it may exclude things like the notification bar), so it's worth taking a look at the documentation.