Is there a way to determine android physical screen height in cm or inches?

Question

I need to know exactly how big the screen is on the device in real units of length so I can calculate the acceleration due to gravity in pixels per millisecond.

Is there a method somewhere in the Android API for this?

Answer 1

Use the following:

    DisplayMetrics dm = new DisplayMetrics();     getWindowManager().getDefaultDisplay().getMetrics(dm);     double x = Math.pow(mWidthPixels/dm.xdpi,2);     double y = Math.pow(mHeightPixels/dm.ydpi,2);     double screenInches = Math.sqrt(x+y);     Log.d("debug","Screen inches : " + screenInches); 

When mWidthPixels and mHeightPixels are taken from below code

private void setRealDeviceSizeInPixels() {     WindowManager windowManager = getWindowManager();     Display display = windowManager.getDefaultDisplay();     DisplayMetrics displayMetrics = new DisplayMetrics();     display.getMetrics(displayMetrics);       // since SDK_INT = 1;     mWidthPixels = displayMetrics.widthPixels;     mHeightPixels = displayMetrics.heightPixels;      // includes window decorations (statusbar bar/menu bar)     if (Build.VERSION.SDK_INT >= 14 && Build.VERSION.SDK_INT < 17)     {         try         {             mWidthPixels = (Integer) Display.class.getMethod("getRawWidth").invoke(display);             mHeightPixels = (Integer) Display.class.getMethod("getRawHeight").invoke(display);         }         catch (Exception ignored)         {         }     }      // includes window decorations (statusbar bar/menu bar)     if (Build.VERSION.SDK_INT >= 17)     {         try         {             Point realSize = new Point();             Display.class.getMethod("getRealSize", Point.class).invoke(display, realSize);             mWidthPixels = realSize.x;             mHeightPixels = realSize.y;         }         catch (Exception ignored)         {         }     } 

See this post for reference: Get screen dimensions in pixels

Answer 2

for getting the current size use Math.round at the end.

 DisplayMetrics dm = new DisplayMetrics();     getWindowManager().getDefaultDisplay().getMetrics(dm);     double x = Math.pow(dm.widthPixels/dm.xdpi,2);     double y = Math.pow(dm.heightPixels/dm.ydpi,2);     double screenInches = Math.sqrt(x+y);     Log.d("debug","Screen inches : " + screenInches);  screenInches=  (double)Math.round(screenInches * 10) / 10;