Develop Reference

Get reported screen width and height

This may end up being a "yes" or "no" question...
Starting in Nougat (maybe marshmallow?), users can change the display size of their device. Specifically on the Galaxy S8 and S8+, the user can change the display resolution.
I've seen the solutions here: Get Screen width and height
QUESTION: Do these solutions give the actual height/width of the screen regardless of changed resolution or do they give the adjusted height/width of the screen if resolution changed?
If the first, how do I get the adjusted height/width?

Interesting question. It gives me adjusted dimensions in pixels. I have tested it now in my Pixel running Android O.
Method 1:
DisplayMetrics displayMetrics = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(displayMetrics);
int height = displayMetrics.heightPixels;
int width = displayMetrics.widthPixels;
Method 2:
Configuration configuration = getResources().getConfiguration();
int screenWidthDp = configuration.screenWidthDp;
int screenHeightDp = configuration.screenHeightDp;
int smallestScreenWidthDp = configuration.smallestScreenWidthDp;
Both methods returned the adjusted dimensions. The first method returns the device screen dimensions. The second method returns the dimensions of the app screen. These two result would vary when there are two apps open in multi-window mode.

Why does screen width and screen change with changing orientation?

I ran an application on my nexus 7 that calculated the screen width and height on my device. In portrait mode, my application gave me a height of 1824 px and a width of 1200 px. These dimensions made sense to me. However in landscape mode, my application gave me a height of 1104px and a width of 1920 px. From Does the Width and Height change with orientation?, I got that with changing orientation, screen width and height change, but shouldnt the dimensions just flip? To me, its the same fundamental screen
The code i used to calculate the screen size
Display display = getWindowManager().getDefaultDisplay();
int height = display.getHeight();
int width = display.getWidth();

Android: Samsung S4 Screen size

I am trying to figure out the dimensions for the S4. What is the width and height. I want to create graphics and place them based on h and w. I read that the screen size ranges from 0-h and 0-w, but what are h and w?

S4 screen specs are 1080 x 1920, but you shouldn't use the actual screen size in pixels in your code.
Just use dp - which is a size which is independent in the screen density to design you Android app UI, this way, it will behave nicely for all screen sizes.
For more details see Supporting Multiple Screens Guidelines.

Here's some handy code if you need to find the size of various devices:
Display display = getWindowManager().getDefaultDisplay();
Point size = new Point();
display.getSize(size);
int screenWidth = size.x;
int screenHeight = size.y;

Change Orientation while converting android handset app to tablet

I am converting and android handset application to tablet (1024*600 and 1280*720). I have given the support for different screen- size, but stuck in orientation part. I want some pages to be visible as landscape. For example after logged in by user the next intent should be in landscape form. After searching I found clue but not very understandable answer such as
By adding activity in manifest.xml file
At runtime by using getOrientation().
Thanks

The question is not clear, if you're forcing screen orientation by size (e.g. on tablet device there's only landscape orientation), i think you should get the screen width and height first then evaluate it. If the screen width and height are 1024*600 or 1280*720, you change the orientation with setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
To get the width and height, do this in your activity:
Display display = getWindowManager().getDefaultDisplay();
int width, height;
try {
Point size = new Point();
display.getSize(size);
width = size.x;
height = size.y;
}
catch (NoSuchMethodError e) {
width = display.getWidth();
height = display.getHeight();
}
See this

auto resizing textView with different density devices android

At the top of my app, I have a title which should be shown in the middle, and a button on the right. As the textViews length is behind my control, I sometimes have my title crossing the button due to long length of the content of it.
After following this, I somehow tend to solve the problem. My device was HTC desire. Unfortunately, if I check with Galaxy SIII, it doesn't do the trick.
I am wondering how I can manage this in terms of different devices with different densities.
My controls inside the relative layout

You can also check the device screen density by this--
WindowManager wm = (WindowManager) _context.getSystemService(Context.WINDOW_SERVICE);
Display display = wm.getDefaultDisplay();
int screenWidth = display.getWidth();
int screenHeight = display.getHeight();
And can manage accordingly whats your apps needed..

just use weightsum in your xml and make width of all the views as fill parent ..... this makes auto resizing of your textview

you can maintain layouts according to their DPI`s
replicate the same XML data in XHDPI (As S3 falls in XHDPI) and test it similarly replicate the XML data in HDPI
but
keep in mind the following Thing Pixel Ratio of the layOut as
following
in LDPI its 1:0.75
in MDPI its 1:1
in HDPI its 1:1.5
in XHDPI its 1:2

Display display = ((WindowManager) ctx.getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay();
DisplayMetrics dm = new DisplayMetrics();
display.getMetrics(dm);
float density = dm.density;
int screenWidth = display.getWidth();
With this code above, you'll have your screen density as float.. So you can use it to calculate your textView's width like:
int newWidth = (int) (density * 100);
which 100 is here based size.
Or you can have a ratio according to your screenWdith.
int newWidth = screenWidth / 2;