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Java Basic Rules




// 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

397LW NO topic_id



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ADT Bundle 22.6.2 have memory leak. | adt-bundle-22-6-2-have-memory-leak


If I trying
android-sdk_r22.6.2-windows.zip
adt-bundle-windows-x86_64-20140321.zip
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memory continues to grow to crashes Eclipse

https://developer.android.com/sdk/index.html

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Copy save Bitmap Image Pictures Android example | save-bitmap-image-android-example


Copy file to another

        File path = Environment.getExternalStoragePublicDirectory(
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            InputStream is = getResources().openRawResource(R.drawable.flower_blue);
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Copy and compress file

Bitmap bitmapOrg = BitmapFactory.decodeResource(getResources(),
					R.drawable.flower_blue);

try {
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Shuffle Array of String Java Example | shuffle-array-of-string-java-example



       String[] sAr = new String[] {"one","two","three"};
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For and continue statement in Java.

public class MainClass {
	public static void main(String[] arg) {
		String[] arrayOfString = { "Hello", "people", "hello", "world!" };

		for (int i = 0; i < arrayOfString.length; i++){
			if(arrayOfString[i].equals("hello"))
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}
/*
Hello
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world!
*/


Editace Jana Žákovská : 2013-12-09 11:06:19
Počet článků v kategorii: 397
Url:java-basic-rules
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