Everywhere in Android documentation I can ready that I have to use sw600dp for 7 inch tablets, but this does not seem to be true, because Galaxy Tab 2 7" has 546dp for its smallest width.
http://www.gsmarena.com/samsung_galaxy_tab_2_7_0_p3100-4543.php
dp = 600 / (170 / 160) = 546
Should I use sw500dp in my layouts instead?
Android device pixel densities are classified in buckets:
While the Galaxy Tab 2 screen may actually be 170 dpi, that falls within the range of mdpi which translates to 160 dpi being used in practice for dp calculations. The device should still have a 600dp width.
Related
I am new to tablet application development. I am having Google Nexus7 with screen resolution (600 * 960 dip) So I want to know is it fall in to mdip category?
According to that 1px = 1dp (baseline). But If I follow this its not looks good on tablet. I am creating separate layout folder for nexus7 -sw600dp and mention sizes according to mdip but it not working. My images also not looking good. What I want to know what is actual conversion rate for google nexus 7. Need help.
Formula: pixels = dips * (density / 160)
The Nexus 7 is 800x1280 with a 213 px density, which means it's resolution code is tvdpi (which means you can have a folder called drawable-tvdpi).
You can measure available screen size, minus window decorations, with:
this.getResources().getConfiguration().screenWidthDp;
this.getResources().getConfiguration().screenHeightDp;
On my N7, it returns 600 dp w, 888 dp h. Following the above formula, 888 dp height is 1280px - window decoration.
The Nexus7 is a unique device, with a somewhat strange dpi structure.
For nexus 7
layout-large-hdpi
Here is a very good explanation (from Dianne Hackborn - an Android engineer at Google): Dianne Hackborn explains the unique resolution of the Nexus7
Note: The app takes images from these folders only if you have not given higher precedence qualifiers. For example if you have given a layout folder like layout-sw360dp the app will take only the images from this folder even if you have given separate layouts like the one I said above. Because in android there is an order of precedence in which you have to give layouts.
Screen Density
Commonly referred to as dpi (dots per inch). Android groups all actual screen densities into four generalized densities: low (120), medium (160), high (240), and extra high (320). A device such as Galaxy Nexus has "extra high" screen density (more specifically, the dpi value is set at 320). The Nexus 7 uses "tvdpi" - i.e. 213 dpi.
Density Independent Pixel
Commonly referred to as dp. This is the virtual pixel unit used when displaying content. The density-independent pixel is equivalent to one physical pixel on a 160 dpi screen. To calculate dp use the following formula:
px = dp * (dpi / 160)
or equivalently:
dp = (px / dpi) * 160
The reason Nexus 7 can show more content than the Galaxy Nexus despite having similar resolutions is this: the dpi of Nexus 7 is lower than Galaxy Nexus.
Galaxy Nexus (320 dpi, 720 pixels wide)
(720 / 320) * 160 = 360 dp
Nexus 7 (213 dpi, 800 pixels wide)
(800 / 213) * 160 = 600 dp
This means that when apps are rendering on the Galaxy Nexus, the width of the screen is actually 360 dp (rendered using 720 pixels). Whereas on the Nexus 7, the width of the screen is 600 dp (rendered using 800 pixels).
Try below code, give pixel value to below method it will give you result in dp.
public int convertSizeToDeviceDependent(int value) {
DisplayMetrics dm = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(dm);
return ((dm.densityDpi * value) / 160);
}
I am using "layout-sw360dp" for both Galaxy S4 and Nexus 4 devices but in my screen displaying some space on Galaxy S4. so can i make different layout for both Galaxy S4 and Nexus 4. if it is possible then please give me the solution.
For Galaxy s4 use layout-xxhdpi
For Nexus 4 use layout-xhdpi
Galaxy S4 -- 1080 x 1920 pixels -- 5.0" -- 441 ppi -- xxhdpi
Nexus 4 -- 1280 x 768 pixels -- 4.7" -- 320 ppi -- xhdpi
You have to make different images to fit to the resolution of these devices
As per other answers one device is 640 x 360 dp and the other 640 x 384 dp.
You don't want to make a different layout for them, because you will sooner or later see a device 640 x 372 dp or 640 x 388 dp.
Instead make your layout elastic and don't hardcode pixels (density independent pixels can also be badly hardcoded).
ok here goes...
for reference
this is older layout folder naming conventions but you get the point.
You must convert everything to mdpi to go into the following buckets.
buckets for layouts are :
xlarge 960 x720 min
large 640 x480 min
normal 470 x 320 min
small 426x 320 min
scaling ratio
3:4:6:8:12
this means that you must multiple ldpi * 3/4 to go from ldpi to mdpi
and you must multiple mdpi * 4/6 to go from mdpi to hdpi
and you must multiple hdpi * 6/8 to go from hdpi to xhdpi
and you must multiple xhdpi * 8/12 to go from xhdpi to xxhdpi
so to answer the question....
s4 is xxhdpi which means the scaling ratio is 4/12 or 1/3. This means that you have to convert from xxhdpi to mdpi to place in a layout folder properly.
so 1080 * 1/3 = 360
and 1920 * 1/3 = 640
so this would place it in a normal layout folder
nexus 4 is xhdpi which means the scaling ratio is 4/8 or 1/2. 4 This means that you have to convert from xhdpi to mdpi to place in a layout folder properly.
so 1280 * 1/2 = 640
and 768 * 1/2 = 384
so this would place it in a normal layout folder as well.
ok, so this doesn't quite cut it because they are different resolutions. we can make up folders with the new naming conventions. for example the smallest width for the s4 is 360 while the smallest width for the nexus 4 is 384. so folders could be sw360dp and sw384dp.
you could also name the folder layout-xxhdpi which would catch the s4 but not the nexus 4
be aware: Just to throw another one out there what if you had an s3 as well. that would go in the sw360dp folder as well. so I guess you would have to differ between them as well. if you used layout-xxhdpi above then you could use sw360dp here and sw384dp above as well. cover them all.
thanks
Both these phones have different screen size and resolution , that leads to different density as well .
As per my knowledge -
Galaxy s4 has 1080 x 1920 pixels, 5.0 inches (~441 ppi pixel density).
And
Nexus 4 has 1280 x 768 pixels, 4.7 inches (320 ppi ).
You will have to design the layouts (and images as well ) according to the phones specifications.
for nexus 4 use below layout.
layout-sw360dp
both galaxy s3 and nexus 4 have same layouts.
I'm trying to understand which layout uses which device.
For instance, I've different layouts:
layout
layout-sw600dp
layout-sw720dp
Nexus 7" (800x1280) uses layout-sw600dp
Samsung GTp3100 7" (600x1.024) uses layout-sw600dp
Samsung Tab 10.1 (1280x800) uses layout-sw720dp
Sony XPERIA S 4.3 (1280x720) uses layout
Can you guys explain "with your words" why isn't XPERIA S using sw600dp or sw720dp?
SW != smallest width? So smallest with from XPERIA S is 720. It should be using sw720 or sw600, right? Or am I wrong?
I've read tons of documentation, but can't understand why is this happening.
Thanks a lot.
The Smallest-Width qualifier refers primarily to screen size and not the physical pixels.
Using sw720dp for example means the device must have a minimum screen width of 720 dp (device-independent pixels) - this isn't about 720 physical pixels. From the documentation...
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.
The physical width of the Sony XPERIA S 4.3 is 2.5" but I don't know how much of that is the actual width of the screen.
Let us pretend for the sake of calculations that the screen covers the full width...in this case to calculate dpi for width we simply use 720 / 2.5 = 288dpi.
From the documentation for dp...
The conversion of dp units to screen pixels is simple: px = dp * (dpi / 160).
Rearranging the formula above to calculate dp we do this...
dp = px / (dpi / 160)
...this gives us the width in dp (and a necessary Smallest-width qualifier) of...
720 / (288 / 160) = 400dp
In short the answer is, the Sony XPERIA S 4.3 may have a high-density screen (for its size) but it isn't a large screen.
According to this guide's chapter px = dp * (dpi / 160) and to that layout specifications change from buckets(physical size in inches) to "dp" units so that:
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).
Since "dp" values depend on "px" and "dpi" values so that: dp = px / (dpi / 160) - isn't it possible that a phone device with high resolution will take a layout from w600dp folder?
For instance: Samsung galaxy s3 dp = 1280 / (303 / 160) = 670; Samsung galaxy s2 dp = 800 / (217 / 160) = 592. So, galaxy s3 is going to take "tablet-oriented" template, right. Is it okay, especially if a tablet version contains more elements and overall interface ergonomics gonna suffer from the tablet layout in case of s3 ? Why don't just stick to display buckets ?
You're probably going to recommend using "sw" key but I just want make sure that those "dp" units actually relate to sizes so that tablet-oriented template won't be shown on phone devices.
So, would you mind sharing your practical knowledge on applying the new approach ?
Thanks
A dp or dip is a (screen) Density Independant Pixel. The confusing part about that is that is mentions pixel. It is actually a unit similar to a centimeter or inch.
Each device defines a dpi bucket for it's screen, for example mdpi which is 160dpi. That means that you find 160 pixel across one inch on the screen. It's not 100% accurate since physical screens are usually not exactly 160 dpi (or whatever value that is defined for the bucket). But it's a value that comes close.
That means that 160dp on a perfect 160dpi screen are actually 160 pixel. On a device with a perfect xhdpi (=320dpi) screen those 160dp would be 320 pixel. (px = 160dp * (320dpi / 160))
To work with dp don't think in pixel. Think in inch, milimeter or what unit you prefer. The recommended 48dp rythm for UI elements for example explains that
On average, 48dp translate to a physical size of about 9mm (with some variability)
To approximate that: 50dp = one finger wide.
That hopefully explains why a typical 320dp phone screen is always smaller than a 720dp tablet screen although the smaller screen can have more pixel than the larger. The dpi / pixel thing is already factored into dp.
How to do different layout for different screensizes? (i.e. phone vs table)
Use the screen size buckets (small, ..., xlarge) for the layout. They represent physical small to large screens. You don't need sw600dp etc unless you need to adjust very special cases.
The different dpi buckets should only concern you for images. E.g. high resolution images for high resolution screens of any size in the drawable-hdpi folder.
The S3 does not have a density of 160.
I have 2 different android phones. The details are
nexus s: 480 x 800 pixels, 4.0 inches (~233 ppi pixel density)
desire s: 480 x 800 pixels, 3.70 inches (~252 ppi pixel density)
Now I have my layout folders as layout_hdpi and layout_xhdpi. Now both these phones are classes as hdpi phones. I have a controls with a padding of 5dip to the left and the right. But on these phones the 5dip translates to different widths hence the border on one phone is fatter then on the second phone. Increasing one also increases the other. Can someone help me please?
for different screen sizes use relative-layouts.. it will not cause the problem of different width on different phones
First of all layout_hdpi and layout_xhdpi should be declared as layout-hdpi and layout-xhdpi.
Secondly, HDPI refers to the range 161–240(ppi). So your Nexus phone is eligible for the HDPI qualifier, but your Desire S is eligible for XHDPI qualifier, because the range of xhdpi is 241–319.