Get Screen Size Pixels per Inch Android example

 Display display = getWindowManager().getDefaultDisplay();
int nWidth = display.getWidth();
int nHeight = display.getHeight();

          DisplayMetrics metrics = new DisplayMetrics();
            getWindowManager().getDefaultDisplay().getMetrics(metrics);
            //get density per inch for example: 120 , 160 , 240
            mXDpi = metrics.xdpi; // 160 The exact physical pixels per inch of the screen in the X dimension. 
            mYDpi = metrics.ydpi;

// density
int nDensity = metrics.densityDpi; // 160 screen density expressed as dots-per-inch

          float  mMetersToPixelsX = mXDpi / 0.0254f; // 1 inch == 0.0254 metre
          float  mMetersToPixelsY = mYDpi / 0.0254f;
          
// Resolution
// The total number of physical pixels on a screen.
int wPix = metrics.widthPixels; // 320 The absolute width of the display in pixels.
int hPix = metrics.heightPixels; // 480 The absolute height of the display in pixels.
int nWidthDisplay = (wPix < hPix)? wPix : hPix;

float nWidthScreenInInch = wPix / mXDpi; //320 / 160 == 2.0 in inch.
float nHeightScreenInInch = hPix / mYDpi; //480 / 160 == 3.0 in inch.

// for example:
// density 120 per inch
//width 320 pix / 120 dpi == width 2.66 inch
//height 480 pix / 120 dpi == height 4.0 inch 

// density 240 per inch
//width 320 pix / 240 dpi == width 1.33 inch
//height 480 pix / 240 dpi == height 2.0 inch 

Button mIdButtonHome = (Button)findViewById(R.id.idButtonHome);
	mIdButtonHome.setOnClickListener(new View.OnClickListener() {
		public void onClick(View v) {
			Intent browserIntent = new Intent(
					Intent.ACTION_VIEW,
					Uri.parse("//android.okhelp.cz/category/software/"));
			startActivity(browserIntent);
		}
	});

public boolean isConnected() {
	 try {
		ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
		 return cm.getActiveNetworkInfo().isConnectedOrConnecting();
	} catch (Exception e) {
		// TODO Auto-generated catch block
		e.printStackTrace();
		Log.e("isConnected", e.getMessage());
		Toast.makeText(getApplicationContext(), e.getMessage(),
				Toast.LENGTH_LONG).show();
		return false;
	}

1. Open in Eclipse menu Help ->Check for Updates


2. Select updates:
   



3. Press Next and update all



4. Restart Eclipse


[caption id="attachment_596" align="alignleft" width="300" caption="Restart Eclipse if updates finished."][/caption]

public class MyActivity extends Activity {
// bla bla bla .......
//error 
myFc( getapplicationcontext());
// OK
myFc(MyActivity.this);