// 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);

// solution 1
ImageView imageView = (ImageView)findViewById(R.id.myimage);
imageView.setImageDrawable(null);
// or
imageView.setImageResource(0);

// solution 2  hide ImageView
imageView.setVisibility(View.INVISIBLE);

// solution 3 resize ImageView 0, 0
 hImageViewSemafor.setLayoutParams(new LinearLayout.LayoutParams(0,0));

public class MainActivity extends Activity implements OnClickListener {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        LinearLayout layout = (LinearLayout) findViewById(R.id.layout);
            RadioGroup radioGroup = new RadioGroup(this);
            
            LinearLayout.LayoutParams p = new LinearLayout.LayoutParams(
                    LinearLayout.LayoutParams.FILL_PARENT,
                    LinearLayout.LayoutParams.WRAP_CONTENT
            );
            layout.addView(radioGroup, p);

            RadioButton radioButtonView = new RadioButton(this);
            radioButtonView.setText("RadioButton");
            radioButtonView.setOnClickListener(this);
            radioGroup.addView(radioButtonView, p);
            
            RadioButton radioButtonView2 = new RadioButton(this);
            radioButtonView2.setText("RadioButton2");
            radioButtonView2.setOnClickListener(mThisButtonListener);
            radioGroup.addView(radioButtonView2, p);
        
    }
    
    public void onClick(View view) {
    	 try {
    	  String s = ((RadioButton) view).getText().toString();
    	  Toast.makeText(MainActivity.this, "This is: " + s,
    			  Toast.LENGTH_LONG).show();
    	 }
    	 catch (Exception e1) {
    	   e1.printStackTrace();
    	 }
    	}
    
    private OnClickListener mThisButtonListener = new OnClickListener() {
        public void onClick(View v) {
        	String s = ((RadioButton) v).getText().toString();
        	Toast.makeText(MainActivity.this, "Hello from 2!" + s,
        			Toast.LENGTH_LONG).show();
        }
    };

}

public class MainClass {
	public static void main(String[] arg) {
		String[] arrayOfString = { "One", "Two", "Three", "Four" };

		int i = 2;
		switch (i) {
			case 1: {
				System.out.println(arrayOfString[i]);
				break;
			}
			case 2: {
				System.out.println(arrayOfString[i]);
				break;
			}
			case 3: {
				System.out.println(arrayOfString[i]);
				break;
			}
			default: {
				System.out.println("Enter a valid value.");
			}
		} // END of switch
	}
}
/*
 * Three
 */

case 1:
 System.out.println(arrayOfString[i]);
break;

// i love this notation 
case 1:{
 System.out.println(arrayOfString[i]);
}break;

case 1:{
 System.out.println(arrayOfString[i]);
 break;
}

// res/values/strings.xml
<string name="link_text_auto"><b>text1:</b> This is some text.  In
      this text are some things that are actionable.  For instance,
      you can click on //www.google.com and it will launch the
      web browser.  You can click on google.com too.  And, if you
      click on (415) 555-1212 it should dial the phone.
    </string>
// main.xml
<!-- text1 automatically linkifies things like URLs and phone numbers. -->
  <TextView xmlns:android="//schemas.android.com/apk/res/android"
            android:id="@+id/text1"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:autoLink="all"
            android:text="@string/link_text_auto"
            />

// MainActivity.java onCreate
/*Be warned that if you want a TextView with a key listener or movement method not to be focusable, or if you want a TextView without a key listener or movement method to be focusable, you must call setFocusable(boolean) again after calling this to get the focusability back the way you want it. */

TextView t2 = (TextView) findViewById(R.id.text2);
t2.setMovementMethod(LinkMovementMethod.getInstance());

// main.xml
<!-- text2 uses a string resource containing explicit <a> tags to
       specify links. -->
  <TextView xmlns:android="//schemas.android.com/apk/res/android"
            android:id="@+id/text2"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:text="@string/link_text_manual"
            />

//strings.xml

<string name="link_text_manual"><b>text2:</b> This is some other
      text, with a <a href="//www.google.com">link</a> specified
      via an <a> tag.  Use a \"tel:\" URL
      to <a href="tel:4155551212">dial a phone number</a>.
    </string>

// MainActivity.java onCreate
        TextView t3 = (TextView) findViewById(R.id.text3);
        t3.setText(
            Html.fromHtml(
                "<b>text3:</b>  Text with a " +
                "<a href=\"//www.google.com\">link</a> " +
                "created in the Java source code using HTML."));
        t3.setMovementMethod(LinkMovementMethod.getInstance());

        SpannableString ss = new SpannableString(
            "text4: Click here to dial the phone.");

        ss.setSpan(new StyleSpan(Typeface.BOLD), 0, 6,
                   Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
        ss.setSpan(new URLSpan("tel:4155551212"), 13, 17,
                   Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);

        TextView t4 = (TextView) findViewById(R.id.text4);
        t4.setText(ss);
        t4.setMovementMethod(LinkMovementMethod.getInstance());