Develop Reference

Layout Issue on Small Screens

I'm working on a Android App. Layout working fine on every device except where device screen size 480x800 & less.
How can create separate layouts by only targeting that screen size or less?
I'm already tried layout-hdpi, layout-small-hdpi & layout-normal-hdpi since phone like Nexus S, Nexus One are in hdpi category. But when I create separate layouts like layout-hdpi those layouts are affecting phone with bigger screen like Pixel, Pixel2, Nexus 5 etc.
Thanks in Advance

Phones (as opposed to tablets) tend to come in about three size groups (as far as Android resources are concerned): those with smallest width of 320dp, those with 360dp, and those with 410dp. The resources framework gives you a way to target any device larger than a certain width, so the correct technique is to put layouts for small screens on the default folder, and layouts for larger screens in one of the qualified folders.
Since it sounds like your layouts currently work well for anything 360dp or larger, you can make two layout directories:
res/
layout/
layout-sw360dp/
Put the special layouts for the small screens inside res/layout/ and put the “normal” layouts in the other directory.

Its not easy but you can also specify layouts based on the smallest width and you you supply the numbers. You can get more detailed and separate layouts that way however in my experience you will still run into that problem from time to time. In my current project using this method I have specific folders for W360 and W400 to deal with smaller devices for one specific screen.
https://developer.android.com/guide/practices/screens_support.html#DeclaringTabletLayouts

What you are looking for, is a layout bucket with the smallest width qualifier.
A layout with a set smallest width will be active, unless the smaller of the both dimensions (width or height) is lower than a certain value you can choose.
So, when a device has a smallest width below some value X it will use the default layout, when the value is X or more it will use the defined smallest width layout.
To create such a layout file in Android Studio, you wanna right-click your layout directory, click on new -> Layout Resource File and select the Smallest Screen Width qualifier from the list of available qualifiers. Now you need to specify your smallest width, which in your case should be slightly above 480dp. Give it the same name as your current layout file. Place your code for devices with a smallest width above 480p here. Now change the code in your other layout file, without the smallest width qualifier, to support smaller screens.
For further reference take a look at the official Android Developer page.

calculate dp for different screen for supporting multiple screens

I know there are many questions like this, I have read many blogs and questions on this and I am not satisfied by what I have understand.
I want to support multiple screens and resolutions like hdpi, xxxhdpi etc.
And i am using dimens.xml for this purpose. But m still unclear about how to calculate exact dp value for different screens.
For example if 48dp x 48dp ImageView is proper for hdpi device, what values should i define for xxhdpi device? Is there any fixed calulation just like there is for drawable images?
I am using these folder for trying to support multiple screens :
values-sw320dp-hdpi
values-sw320dp-xhdpi/xxhdpi/xxxhdpi
There are few problems I am facing currently
Though defining values in respective dimens.xml works almost for most of the devices, there are few devices which takes wrong values
For example I have Lg optimus G that is xhdpi device, but it reads values from values-sw320dp-xxxhdpi's dimens.xml instead of xhdpi one
I am not able to calculate the exact value for each resolution (hdpi,xhdpi etc), so the view which looks perfect in hdpi device, seems little large or small in xxxhdpi as I can't guess the value like if hdpi view size is 48dp then xxxhdpi should be of 64dp or something as I don't know the exact approach.
Also while searching for supporting different screens, I read many times about calculating dp at runtime based on density or calulating pixels etc.
I am too confused about all this. Please help me in understanding and learning the proper way of making responsive apps.

You can use resource qualifiers to specify different sizes for Views.
If you want the width of an ImageView to vary based on the size of the screen, create a new dimension in your dimens.xml file called image_view_width (for example).
This then essentially creates a copy of the dimens.xml but adding the 'Size' qualifier. This will create another version of the dimens.xmlfile, and any device that meets your specified qualifications will use that version of dimens.xml. You then add image_view_width to this new file and give it a different (smaller/bigger) value. You can do this as many times as you want and with as many different qualifiers as you want.
Finally, when you want to use this value in your layouts, you only have to type:
android:layout_width="#dimen/image_view_width"
and android will do the rest for you.
Hope this helps!

Density-specific layouts vs. size-specific layouts in Android

For quite a long time, I have been declaring resource folders for 4 different densities:
drawable-ldpi
drawable-mdpi
drawable-hdpi
drawable-xhdpi
In the layout's XML, I have been using fixed widths (while still density-independent) such as 128dp for those graphics.
However, when more and more large-screen phones, and especially tablets, were introduced, that approach did not work anymore. Although you provide density-independent resources this way, the layout will not look good on large screens.
This is why I think I need to add Dimension resources that depend on the screen size, for use in the XML layouts, e.g.:
values
values-w600dp
values-w720dp
values-w1024dp
But does that mean that I should drop supporting those 4 density containers? Or do I need to provide 16 resource folders, i.e. one for every combination of density and size?
I can't find any good help in the Android documentation as to this topic.

drawables and layouts are different. To answer your question, should you stop support those densities. Yes, but you should still support xdpi and hdpi. Romain Guy recently said that modern devices like the Nexus 7 (at a tvpi) can scale the assets properly enough that mdpi isn't really needed. And nobody uses ldpi anymore. Last I looked is was less than 2% of the market.
About layouts. A Nexus 7 (1280x800 tvdpi) would use something from the values-w1024dp but still get assets from the drawable-hdpi folder. Those two aren't mutually exclusive. Something like a S3 would also pull from the values-w1024dp but use drawable-xdpi. You only need to provide an alternative layout if your use-case calls for it.
So do you need 16 different things? No. You do need xdpi & hdpi (if not mdpi). You may want to include alternative layouts for different sizes. You can be as specific as you want or as generic. Unless you're doing a hybrid app for both phone & tablet (7 & 10 in) you probably don't need a lot of xxxx-sizexxx folders.
In the layout's XML, I have been using fixed widths (while still density-independent) such as 128dp for those graphics.
This is probably a source of your issues. Your layouts should be as fluid as possible using wrap_content and match_parent. Fixed sizes should be reserved for padding around the sides and image where you know the size ahead of time. If you do this, your layout should look decent at any size from a small 320 x 200 to a GTV size.

1) Regarding dimensions in your layouts (values/dimens.xml):
values values-w600dp values-w720dp values-w1024dp
But does that mean that I should drop supporting those 4 density
containers? Or do I need to provide 16 resource folders, i.e. one for
every combination of density and size?
No, you don't need to provide different dimensions per dpi bucket (hdpi/xhdpi), because the dimensions are already being scaled up or down based on the device (if you're using dp instead of px). So for dimensions, you only need to provide values for devices with different sizes (hence the name, values-smallest possible width-600-dp). Because you don't want 16dp padding on a phone AND 16dp on a 10" tablet as well. You'd want 64dp instead. And no, it doesn't matter what density the device has. It still needs to have the same padding on the respective device width. So for dimens, you only need to think about the device's actual physical dimensions.
2) Regarding drawables scaling for different resolutions (drawables/xdpi):
The system scales them appropriately for the device. You don't need to worry about this. Also, you don't need to add any other buckets here. Just use mdpi/hdpi/xhdpi and maybe xxhdpi because many new devices are going to use the new density in the future.
Conclusion: there are 2 different UI building components that vary according to 2 different rules: drawables based on screen density and dimensions based on screen size. Do not mistake one for the other and think you need tens of buckets in the values folder, because that's not only wrong, it's just mind boggling.

android drawable folder for large screens

I have images in drawable-hdpi(big images) and in drawable-mdpi(small images)
I opened my app on Kindle fire (its get layout from layout-large) and it use images from
drawable-mdpi , is any way to let app to get images from drawable-hdpi when screen size is large?
thanks

I think what you are looking for is to use configuration qualifiers.
It seems you are really misunderstanding what these folders do.
Your android will select folder based on it's screen size or pixel-density.
Your Kindle Fire has a medium Pixel density and a large screen. So it selects its resources from the res folders with those given qualifiers.
res/layout-large/my_layout.xml
and images from
res/drawable-mdpi/my_icon.png
You cannot tell your kindle to get images from the hdpi folder because it does not have a high pixel density.
So you could either create a folder called
res/drawable-large-mdpi/
specifically for your Kindle Fire device.
Or just make sure the right images are in the right folders.
EDIT: Size qualifiers are deprecated from 3.2.
While deprecated, they still work. Although results may not be what expected (for example: 5" and 7" are seen as same size -large-which still have difference). So they added dp qualifiers to use beyond 3.2. Which are much better. developer.android.com/guide/practices/… It kinda works like media-queries

Updating this with the new qualifiers for Android.
Use of size qualifiers such as drawable-large are deprecated in 3.2 or above.
To use the latest method of supporting multiple layouts and densities, you can use the following:
res/drawable-sw600dp-mdpi
In this example, sw600dprepresents the smallest width available to the activity in density-independent pixels,600dpin this case. This is deemed as being a little more fitting for device-specific layouts and drawables as the width is provided instead of a generalized size grouping such aslarge`.
There are also new options for available width and height, full information available here: Supporting Multiple Screens

All qualifiers are processed in the order they appear in Table2.
Read How Android Finds the Best-matching Resource.

Resolutions and densities

I am developing for android and my code runs perfect on nexus or any 3.7 inch device.
If I run it on tablet (7 or 10.1 inch) then the fonts and buttons are very small and the spacing is way too big.
If I run it on 2.7 QVGA then the buttons are too big and overlap.
I am using dp and sp all over the layout so I am surprised it didn't adjust according to different screen size/density.
Does that mean that I have to wrte the same XML layout in 3 layout folders (large, medium and small) and put my drawable in 3 different density folders?
Or am I amissing something here. Yes I read the "Supporting multiple screen" document and it just loses me with the details (but I did follow the tips of using dp and sp). I am looking for more of a summary/general approach answer.

dp and sp adjusts according to screen density. Therefore, a screen with 500 dpi and 4000 dpi but with the same SCREEN DIMENTIONS will looks the same.
If they have different screen sizes, it won't fit as you want. If you want to support multiple screen sizes, you'd have to use weights or percentages.
The key is that dp = device independent pixel and it only adjusts according to density, not screen size.

In the most cases if you don't make a tablet app, you don't need to make more than one XML layout for different densities/sizes. All you must do is define dimensions with DP and SP as you said.
But is necessary to provide different images in the drawable folder to show one or other in function on screen size/density.
If you put all images in drawable folder (without specify hdi,ldi or mdi) Android will try to adjust the images but not always works fine.
Hope it helps.