Pixel to density independent pixel to pixel conversion

// file name MyFirstClass.java

import java.util.*;
import java.lang.Math;
import java.io.*;
import javax.swing.*;

public class MyFirstClass{ // start of program
  public static void main(String[] args) { // basic  function main

// variables and calculation
int a=2;
int b=3;
int c=Integer.parseInt(JOptionPane.showInputDialog(" Put number: ", "1"));
System.out.println("Number is: "+c);
System.out.println(a+" * "+b+" = "+(a*b));
System.out.println("a^3 "+Math.pow(a,b));

//array
int[] array_my=new int[10];
array_my[0]=3;
array_my[1]=5;
System.out.println("Number of elements "+array_my.length+" 1 + 2 element of array "+(array_my[0]+array_my[1]));

//strings
String txt="Quick red fox";
String txt2=JOptionPane.showInputDialog("Write text: ", "word");
System.out.println("Text is: "+txt2);
String[] count_of_word=txt.split(" ");
System.out.println("Length: "+txt.length()+" Count of words "+count_of_word.length);
System.out.println(txt +" -> "+txt.replace("red","brown"));
System.out.println("First 5 chars of string is: "+ txt.substring(0,5));

//for a if
for(int i=0; i<10;i++){
	if(i==3)System.out.println("i equal "+i);
	}

// file
try {
  File soubor=new File("some_file.txt");
  if(!soubor.exists()){
	System.out.println("File dont exist");
  }
  else { // utf-8 encoding
    BufferedReader in1 = new BufferedReader(new InputStreamReader(new FileInputStream(soubor),"UTF-8"));
    BufferedWriter out1 = new BufferedWriter(new OutputStreamWriter(new FileOutputStream("zapis.txt"),"UTF-8"));
    String str;
      while ((str = in1.readLine())!=null){
        System.out.println(str);
        out1.write(str+"

");
      }
    in1.close();
    out1.close();
   }
 } catch(IOException e){System.out.println("Error " + e);}

// dir
 File pathName = new File("some_dir");
 String[] fileNames = pathName.list();
 if(pathName.exists())
 System.out.println("Name of first file in  \"some_dir\": "+fileNames[0]);
 else System.out.println("dir not exist");

//function
int nResult = calculateMyFc(3,5);
System.out.println("Result of function: "+nResult);

} // end of function main

// new function , you can add to end MyFc = my function
public static int calculateMyFc(int a, int b){
return (a+b);
}

} // end of class of program

// .............. blah
    <uses-sdk android:minSdkVersion="4"/>
   <uses-permission android:name="android.permission.INTERNET" />
   <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

    <application android:icon="@drawable/dicts_ico" android:label="@string/app_name" 
    >
           <meta-data 
        android:value="a12345_your_number" 
        android:name="ADMOB_PUBLISHER_ID" />
        <activity android:name=".MainStartMenu"
                  android:label="@string/app_name"
                  android:configChanges="keyboardHidden|orientation"
                  >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                 <category android:name="android.intent.category.DEFAULT" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>


  <!-- Google ads -->      
<activity android:name="com.google.ads.AdActivity"
              android:configChanges="keyboard|keyboardHidden|orientation"/>

// ......... blah 

public class ApokusActivity 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();
			
            paint.setColor(Color.YELLOW);
            paint.setTextSize(60);
            //paint.setTextAlign(Paint.Align.CENTER);

            canvas.drawText("Hello world!", 0, 50, paint);
		}

	}
}

@Override
    public void onDraw(Canvas canvas) {
    canvas.drawColor(Color.GREEN);
}