Compressing a bitmap to JPG format Android example

Android development
Java float is 32 bit single precision type and used when fractional precision calculation is required.

Java float je 32 bitů veliké číslo sloužící především pro přesný výsledek za desetinnou tečkou například při dělení čísel. Pro větší přesnost použíijte 64 bitový typ Double.

		// declaration and assignment of value  type float
		float x = 18.41785f;
		//print formated  value
		System.out.printf("The value of x is %.3f%n", x); // 18.418
                
                // declaring more variables in single statement
                float f1 = 12.4F, f2 = 564.5F, f3 = 14.589F;

		// float range of value
		System.out.println(Float.MIN_VALUE); // 4E-45
		System.out.println(Float.MAX_VALUE); // 4028235E38

		// is NaN  Not-a-Number
		float f = (float) Math.sqrt(-15);
		boolean bNaN = Float.isNaN(f);
		System.out.print(bNaN); // true
		
                // check if a string is a valid number in Java example
                // convert string to float Java example
		String sF = "12.8";
		float fParse = Float.parseFloat(sF);

	       // convert strings to numbers
	      String sFl = "15.48";
	      float fFromString = (Float.valueOf(sFl)).floatValue();

// float to string in Java example code
Float fObj = new Float(68.5);
String str = fObj.toString();
// else 
Float fS = 11.6f;
String sFloat = fS.toString();

              // compare two float variables
	      Float fComp1 = 4.3f;
	      if(fComp1.equals(4.3f))
	  		System.out.print("true");

	    // compares the two specified float values in Java example
	    int i =	Float.compare(11.5f, 11.7f); // -1 first < second
	    // 0 first == second
	    // 1 first > second
	    System.out.print(i);

onSaveInstanceState, onRestoreInstanceState , save preferences

int mCurrentPhotoIndex = 0;
   @Override
    protected void onSaveInstanceState(Bundle outState) {
        outState.putInt("photo_index", mCurrentPhotoIndex);
        super.onSaveInstanceState(outState);
    }

    @Override
    protected void onRestoreInstanceState(Bundle savedInstanceState) {
        mCurrentPhotoIndex = savedInstanceState.getInt("photo_index");
        super.onRestoreInstanceState(savedInstanceState);
    }

// or save preferences for new start of Activity in onStop
//onCreate or onResume or onStart etc.
public void loadPreferences() {
		SharedPreferences settings = getSharedPreferences(F.PREFERENCES_NAME, 0);
		mCurrentPhotoIndex = settings.getInt("mCurrentPhotoIndex",mCurrentPhotoIndex);
	// String_sOtazka = settings.getString("_sOtazka", _sOtazka);


}
// onStop
public void savePreferences() {
		SharedPreferences settings = getSharedPreferences(PREFERENCES_NAME, 0);
		SharedPreferences.Editor editor = settings.edit();
		editor.putInt("mCurrentPhotoIndex", mCurrentPhotoIndex);
                // String, boolean, float ...
		// editor.putString("mButton1", mButton1.getText().toString());

		editor.commit();

}

if , else if, else statement with string as a switch statement in Java example source code.

MainClass.java

public class MainClass {
	public static void main(String[] arg) {
		String[] arrayOfString = {"nothing", "Hello", "people"
				, "bye-bye", "hello", "world!", "end" };
		for (int i = 0; i < arrayOfString.length; i++) {
			
			if (arrayOfString[i].equals("Hello"))
				System.out.println(arrayOfString[i]);
			else if (arrayOfString[i].equals("people"))
				System.out.println(arrayOfString[i]);
			else if (arrayOfString[i].equals("hello"))
				System.out.println(arrayOfString[i]);
			else if (arrayOfString[i].equals("world!"))
				System.out.println(arrayOfString[i]);
			else // default
				System.out.println("Default");
		}
	}
}
/*
Default
Hello
people
Default
hello
world!
Default 
 */

Canvas, drawLine(), setStrokeWidth(), Paint, setAntiAlias(boolean), onDraw()

public class MainActivity extends Activity {
	@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.YELLOW);
			Paint p = new Paint();
			// smooths
			p.setAntiAlias(true);
			p.setColor(Color.RED);
			p.setStrokeWidth(4.5f);
			// opacity
			p.setAlpha(0x80); //
			// drawLine (float startX, float startY, float stopX, float stopY,
			// Paint paint)
			canvas.drawLine(0, 0, 40, 40, p);
			canvas.drawLine(40, 0, 0, 40, p);

		}

	}
}

public class MainActivity extends Activity {
	
	@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) {
			Paint paint = new Paint();
			
			canvas.drawColor(Color.GREEN);
            
            Bitmap b = Bitmap.createBitmap(200, 200, Bitmap.Config.ALPHA_8);
             paint.setColor(Color.BLUE);
            
           Canvas c = new Canvas(b);
           c.drawRect(0, 0, 200, 200, paint);
           
           canvas.drawBitmap(b, 10,10, paint);
		}

	}
}