I am having two android devices which are having the same resolution and PPI. But when i run my application for one device that is Samsung Tab 4, the resources are called from normal layout folder. But for another device that is Samsung J Max, it is from layout-600 folder. Why this is behaving differently for these devices? Any suggestions would be greatly appreciated.
You should check This Google Article. It pointed out that:
In this context, the Samsung has another little surprise: If you do the arithmetic, its screen has 170 DPI, which is far from the densest among Android devices. Still, it declares itself as “hdpi” (and as having a “large” screen size). The reason is simple: It looks better that way.
That means your Tab ppi is 170 (not 220ppi). As a result: 800 width, 170 ppi --> 800/(170/160) > 600. That's why your Samsung Tab 4 resource is from folder "layout-sw600dp"
The 600 qualifier in layout-600 has to do with the screen dimensions in dp and not necessarily with the DPI or the screen resolution in pixels. Other factors like the aspect ratio and the diagonal size of the screen are also taken into consideration.
You can determine the dimensions of your screen in dp programmatically using the instructions in this post:
Configuration configuration = yourActivity.getResources().getConfiguration();
int screenWidthDp = configuration.screenWidthDp; //The current width of the available screen space, in dp units, corresponding to screen width resource qualifier.
I bet that the value of screenWidthDp is different between those devices.
This depends on Density Pixels(dp) of Android Devices which very from device to device and according to that Android device detect automatically from which layout folder it will show the UI, here is the little information how it works :
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
A set of six generalized densities:
ldpi (low) ~120dpi
mdpi (medium)
~160dpi
hdpi (high) ~240dpi
xhdpi (extra-high) ~320dpi
xxhdpi
(extra-extra-high) ~480dpi
xxxhdpi (extra-extra-extra-high) ~640dpi
For more info please read google doc :https://developer.android.com/guide/practices/screens_support.html
Related
I am working on Andoid application for mobile only(Not for Tablet). So I am going to tell designer to make PSD for android screens. Generally I tell my designer for making application design on these three sizes and I use dimen to adjust layout for other devices:
320* 480 (and I put these images into mdpi folder)
480*800 (I put these images into hdpi folder)
800*1280 (I put these images into xhdpi folder)
So I want to know what size of PSD should I made from my designer.I am asking about complete screen size.
//For Designer
start design PSD file from 100% i.e design from XHDPI then need to downscale it to
75% for HDPI
and 50% for MDPI
//For Developer
start design for MDPI first then place drawables in appropriate folder
Baseline phone mdpi 320x480
from that you can increase you drawables as 1.5 for HDPI and 2 for XHDPI
Developer keep in mind while designing layout ref best Practices
1. Use wrap_content, fill_parent, or dp units when specifying
dimensions in an XML layout file.
2. Do not use hard coded pixel values in your application code
3. Do not use AbsoluteLayout (it's deprecated)
4. Supply alternative bitmap drawables for different screen densities
Different screen pixel ratio :-
ldpi = 1:0.75
mdpi = 1:1
hdpi = 1:1.5
xhdpi = 1:2
xxhdpi = 1:3
so lets take an image with about the size of 100X100:
for mdpi it should be 100X100
for ldpi it should be 75X75
for hdpi it should be 150X150
for xhdpi it should be 200X200
for xxhdpi it should be 300X300
http://developer.android.com/guide/practices/screens_support.html
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
I'm a little confused about how to determine which phones support what layout types. I've done some research but haven't found a satisfying answer.
For example, I've found the below guide:
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
However, I still have some concerns:
Samsung grand (480*800) and HTC wild fire S (320*480) both support MDPI. These screens have very different resolutions, yet have the same layout type?
Galaxy note 2 (1280*720) support HDPI. If HD (720p) is only HDPI, when what device/resolution supports XHDPI?
I've already asked a related question here: How to set layout on 7" two different tablet?.
My most important question, however, is this: How do I know which devices or screen resolutions support each layout type?
Android treats mdpi (160 pixels/inch) as the base density. So for mdpi devices, 1 dp = 1 pixel. At higher densities, there are more pixels per inch (240 for hdpi, 320 for xhdpi).
AutoMatic Scaling by Android itself:
Android attempts to make graphic images occupy the same physical dimensions on the screen regardless of the device pixel density. So if all it finds is an mdpi resource, and the device is hdpi, it will scale the graphic by 240/160 = 150%, and it will double the size of the graphic for xhdpi.
Using different versions of graphics :
If you don't want this automatic scaling (which can make graphics look poor), you can simply supply your own version of graphic resources for use at higher densities. These graphics should be of the same size that Android would scale an mdpi resource.
Note : the pixels/inch that was stored in the image file has nothing to do with this. It's all based on where you put the graphics files in the resources directory for your project. Any graphics placed in res/drawable are assumed to be properly sized for mdpi displays, as are graphics placed in res/drawable-mdpi. Image files that it finds in res/drawable-hdpi are assumed to be properly sized for hdpi displays, etc. When your program runs on a particular device, Android will first look for a graphic that matches the display density of that device. If it does not find one but instead finds one for a different density, it will use that and automatically scale the image based on the above rules.
As the ldpi, mdpi and hdpi refer to screen density, which means how much pixels can fit into a single inch.
the ratio in pixels between them is:
ldpi = 1:0.75
mdpi = 1:1
hdpi = 1:1.5
xhdpi = 1:2
xxhdpi = 1:3
so lets take an image with about the size of 100X100:
for mdpi it should be 100X100
for ldpi it should be 75X75
for hdpi it should be 150X150
for xhdpi it should be 200X200
for xxhdpi it should be 300X300
this way, for screens with the same size but different DPI, all the images seem the same size on screen.
look into these details: android manages all this by itself, you just have to provide layouts and images in relative folders
res/layout/my_layout.xml // layout for normal screen size ("default")
res/layout-small/my_layout.xml // layout for small screen size
res/layout-large/my_layout.xml // layout for large screen size
res/layout-xlarge/my_layout.xml // layout for extra large screen size
res/layout-xlarge-land/my_layout.xml // layout for extra large in landscape orientation
res/drawable-mdpi/my_icon.png // bitmap for medium density
res/drawable-hdpi/my_icon.png // bitmap for high density
res/drawable-xhdpi/my_icon.png // bitmap for extra high density
I am designing a background for my app for all Android devices.
I was thinking what would be the size of the image in pixels?
From the developer site I found the following equation
px = dp * (dpi / 160)
Then, px depends on two variables.
First, dp, and we have
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
Second, dpi and we have
low-density (ldpi) screens (~120dpi).
medium-density (mdpi) screens (~160dpi).
high-density (hdpi) screens (~240dpi).
extra high-density (xhdpi) screens (~320dpi).
So where should I put my drawables in the Screen characteristic? I mean should I use "size" or "Density". If I classify my images using the "size" "dp", what is the dpi for these images?
and if I classify my images using the "density" "dpi", what is the dp for these images?
I am confused on how to finally size my images. Also, Maybe you can have a medium density screen with a large screen size, right?
There are many many different resolutions out there. For instance there could be 4 different devices which are:
640 px x 480 px
The difference is, some of these devices are mdpi, some are hdpi, xhdpi etc. meaning they could be described as "large", "medium" or "xlarge" screen types.
So, for an mdpi device which is 640x480dp the background would be 640x480px however, a device which is 640x480dp and hdpi would need a background which is 960x720px, you'll notice they're the same size "bucket" but have different densities and therefore different resolutions.
So, if you just want your background to fit as well as can be expected you'll need:
large-xhdpi
large-tvdpi
large-hdpi
large-mdpi
large-ldpi
(then the same for normal)
normal-xhdpi
normal-tvdpi
etc etc etc.
You're best bet however is to use an image which can stretch, a shape, tile or can be converted to a 9-patch because it would be a pain in the rump to make every background available for every device. If you were going to do it I would look up a resource descrivbing every screen dimension on the market currently and setting it via programmatic methods.
So I get the whole Android pixel independency thing.
I'm creating a SplashScreen that is using a 9patch that will stretch its edges to account for all screensizes.
I also use a differenlty sized 9patch image in ldpi mpdi hdpi xhdpi for each splash screen as well.
That way the logo (the non stretched area of the 9patch) will be the correct size.
I know mdpi is 1.0 and hdpi x1.5 in relative size and xhdpi is x2, but when I'm creating that first mdpi image how do I know how many pixels wide/high it should be?
Hope that makes sense.
Really there's no one answer. Firstly though, I wouldn't start at mdpi and scale up -- It's best to start at the highest quality that you can. Vector, if it fits the design, or a high resolution image (even larger than the largest screen size you currently plan to support). Then, from there, just downsize for the device that you plan to test. For example, a typical HDPI resolution would be 480 x 800, so fit it appropriately there. An XHDPI resolution might be something like 1280 x 720. It's best to just leave a good amount of margin on the edges in case it's used on a device with a different aspect ratio, or something. But yeah, basically, design as large as you can, and then just export based on some average screen resolutions for the density bucket you're working on.
(...) when I'm creating that first mdpi image how do I know how many pixels
wide/high it should be?
Since mdpi is the baseline for all other density buckets, 1dp on an mdpi device will translate to exactly 1px. In other words, use an mdpi device to figure out the relative size on the screen and from there on apply the given scaling ratios to produce resources for the ldpi, hdpi and xhdpi buckets. Obviously you do not actually have to scale up that mdpi resource - all you need determine is the size for that screen density and then you can use whatever source file to produce images for all buckets.
The link xBroak has given, is actually the best source of information regarding your question. A quote from there to support above statements:
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.
It may also come in handy to be aware of the simple d(i)p to px formula (also from that same link):
The conversion of dp units to screen pixels is simple: px = dp * (dpi
/ 160)
With this information, you can easily verify that 1dp on an mdpi device (with 160dpi screen) is equal to 1px. Just fill in 160dpi and you get px = dp * (160 / 160), which simplifies to px = dp * 1, and hence px = dp for 160dpi. QED. :)
These are your basic guidelines:
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
320dp: a typical phone screen (240x320 ldpi, 320x480 mdpi, 480x800 hdpi, etc).
480dp: a tweener tablet like the Streak (480x800 mdpi).
600dp: a 7” tablet (600x1024 mdpi).
720dp: a 10” tablet (720x1280 mdpi, 800x1280 mdpi, etc).
More info: http://developer.android.com/guide/practices/screens_support.html
I've read 10 articles yet still cant find any relation between ldpi, mdpi, hdpi and the actual dimensions in pixels!? Can anybody give a straightforward answer please(if there is one!)
I'm basically trying to put together a splash screen that needs to work on multiple devices without stretching - but i'm struggling as everything I try is either squashed or stretched!?
Cheers
Paul
The ldpi, mdpi and hdpi refer to screen density, which means how much pixels can fit into a single inch.
the ratio in pixels between them is:
ldpi = 1:0.75
mdpi = 1:1
hdpi = 1:1.5
xhdpi = 1:2
xxhdpi = 1:3
xxxhdpi = 1:4
so lets take an image with about the size of 100X100:
for mdpi it should be 100X100
for ldpi it should be 75X75
for hdpi it should be 150X150
for xhdpi it should be 200X200
for xxhdpi it should be 300X300
for xxxhdpi it should be 400X400
this way, for screens with the same size but different DPI, all the images seem the same size on screen.
Also you have multiple screen size types small, normal, large, xlarge and each one of them can be ldpi, mdpi, hdpi, xhdpi, xxhdpi (Nexus 10) or xxxhdpi.
You can try to create a splash screen image that fit to each and every screen type
which gives you 4*5 = 20 different images (it seems to much for me).
For now only the Nexus 10 is at the xxhdpi category.
Install ImageMagick and use this shell script to generate your splash and icon files for multiple devices - iOS, Android, Bada and Windows Phone. You can use cygwin/gitbash if you are on Windows
I just did and I'm pretty happy with it :-)
The screen sizes are inside the script and are -
480x800 - screen-hdpi-portrait.png
320x200 - screen-ldpi-landscape.png
720x1280 - screen-xhdpi-portrait.png
320x480 - screen-mdpi-portrait.png
480x320 - screen-mdpi-landscape.png
200x320 - screen-ldpi-portrait.png
800x480 - screen-hdpi-landscape.png
The definitions are:
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. (Android does not currently
support screens smaller than this.)
Also, check out this blogpost from Dianne Hackborne:
http://android-developers.blogspot.com/2011/07/new-tools-for-managing-screen-sizes.html
Probably the easiest thing is to use an image view and set the scaletype to CENTER_CROP.
(Scale the image uniformly (maintain the image's aspect ratio) so that both dimensions (width and height) of the image will be equal to or larger than the corresponding dimension of the view).
Make sure that you use the src tag rather than setting the background.
<ImageView
android:id="#+id/home_video_layout"
android:src="#drawable/splash_image"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:scaleType="centerCrop"
/>
Updated:
Understanding Screen Densities and the “dp”
Resolution is the actual number of pixels available in the display, density is how many pixels appear within a constant area of the display, and size is the amount of physical space available for displaying your interface. These are interrelated: increase the resolution and density together, and size stays about the same. This is why the 320x480 screen on a G1 and 480x800 screen on a Droid are both the same screen size: the 480x800 screen has more pixels, but it is also higher density.
To remove the size/density calculations from the picture, the Android framework works wherever possible in terms of "dp" units, which are corrected for density. In medium-density ("mdpi") screens, which correspond to the original Android phones, physical pixels are identical to dp's; the devices’ dimensions are 320x480 in either scale. A more recent phone might have physical-pixel dimensions of 480x800 but be a high-density device. The conversion factor from hdpi to mdpi in this case is 1.5, so for a developer's purposes, the device is 320x533 in dp's.
I have found this online dip <--> pixels calculator very useful.
https://pixplicity.com/dp-px-converter/
I support previous answers but don't forget the power of Draw9Patch or using NinePatchDrawables
These refer to screen pixel density, not screen dimension. You need to look into screen size specifiers like small, medium, large, and xlarge instead if you really need to change behavior based on screen size in pixels.
The Android docs explain what densities and sizes match these identifiers.
Android devices can have different width-to-height ratios, while your image has a fixed one. If you do not want your image stretched, you will have to fill the blank spaces above and below or left and right.