Shared Preferences file path Android

Date difference in millisecond between two date, GregorianCalendar, Calendar, after(), befor(), getTimeInMillis().

public class HoriziontalScrollActivity extends Activity {
TextView txtV;
	Context cntx;
	
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        txtV = (TextView)findViewById(R.id.idLabel);
        cntx = this;
        StringBuilder strBuild = new StringBuilder();
        Calendar firstDate = new GregorianCalendar(2011, Calendar.DECEMBER, 31);
        Calendar secondDate = new GregorianCalendar(2012, Calendar.JANUARY, 1);

        
        Boolean bDetermine = firstDate.after(secondDate);            // false
        strBuild.append("Is firsDate after secondDate? " + bDetermine + "

");
        bDetermine = firstDate.before(secondDate);                   // true
        strBuild.append("Is firsDate before secondDate? " + bDetermine + "

");
        
        
        long differenceInMillisecond = 0L;
         differenceInMillisecond = secondDate.getTimeInMillis()-firstDate.getTimeInMillis();
         // second == 1000 millisecond
         long second = differenceInMillisecond / 1000L;
         strBuild.append("Difference between two dates is: " + second + "

");
        
         txtV.setText(strBuild);

    }
  
}

Bitmap Width, Height without memory allocation:

BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeResource(getResources(), R.id.myimage, options);
// now opts.outWidth and opts.outHeight are the dimension of the
// bitmap, even though Bitmap is null
int imageHeight = options.outHeight;
int imageWidth = options.outWidth;
String imageType = options.outMimeType;

Physical pixel (px)
Density independent pixel (dp)
Dots per inch (dpi) .. physical pixels per inch
px = dp * (dpi / 160)

public static int dpToPx(int dp)
{
    return (int) (dp * Resources.getSystem().getDisplayMetrics().density);
}

public static int pxToDp(int px)
{
    return (int) (px / Resources.getSystem().getDisplayMetrics().density);
}

drawRect(), Paint, setStroke(), setStyle(), Canvas example source code.

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(new SampleView(this));
	}

	private static class SampleView extends View {

		// CONSTRUCTOR
		public SampleView(Context context) {
			super(context);
			setFocusable(true);

		}

		@Override
		protected void onDraw(Canvas canvas) {

			canvas.drawColor(Color.CYAN);
			Paint p = new Paint();
			// smooths
			p.setAntiAlias(true);
			p.setColor(Color.RED);
			p.setStyle(Paint.Style.STROKE); 
			p.setStrokeWidth(4.5f);
			// opacity
			//p.setAlpha(0x80); //
//drawRect (float left, float top, float right, float bottom, Paint paint) 
			canvas.drawRect(10, 10, 30, 30, p);
		}

	}
}

R.string to string Android source code
R.array to string [] Android source code

String s = getResources().getString(R.string.my_string); // Hello world!!
String[] arrayOfStrings = getResources().getStringArray(R.array.my_array); // one, two

<xml version="1.0" encoding="utf-8">
<resources>
    <string-array name="my_array">
        <item>one</item>
        <item>two</item>
    </string-array>
<string name="my_string">Hello world!!</string>
</resources>