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Get text file content from raw folder to StringBuilder Android example


StringBuilder, res/raw folder, try catch finaly throws, BufferedReader, InputStream, openRawResource, getResources Android example


public class MainActivity extends Activity {
TextView txtV;
	Context cntx;
    public void onCreate(Bundle savedInstanceState) {
        txtV = (TextView)findViewById(R.id.idLabel);
        cntx = this;
        try {
			StringBuilder strBuilder = myFunction(cntx);
		} catch (IOException e) {

    private StringBuilder myFunction(Context context) throws IOException {
        final Resources resources =  context.getResources();
        InputStream inputStream = resources.openRawResource(R.raw.my_file);
        BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
        StringBuilder strBuild = new StringBuilder();
        try {
            String line;
            while ((line = reader.readLine()) != null) {
        } finally {
       return strBuild; 

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Další témata ....(Topics)


Android studio list of useful shortcuts or like Eclipse | android-studio-list-of-useful-shortcuts

File -> Settings -> Keymap you can do select Eclipse keymap from drop down menu

Ctrl+Shift+A (Help | Find Action on the main menu) and start typing the name of the action. Choose the desired action from the suggestion list.

Ctrl+Click (on Windows) or Cmd+Click (on MacOS) a tab in the editor to navigate to any part of the file path. Select the necessary element in the drop-down, and the corresponding file path opens in an external browser (e.g., in the Explorer, if your OS is Windows).


Find - Rename

Ctrl+F find

Refactor | Rename: Shift+F6  ( +F6)

Find and replace: CTRL + R

Go to variable declaration: CTRL + B

Ctrl+Shift+I (View | Quick Definition)

Ctrl+Alt+F7  (Edit | Find | Show Usages in the main menu)

Ctrl+Shift+F find in project

Ctrl+Shift+F7 (Edit | Find | Highlight Usages in File) to quickly highlight usages of some variable in the current file.
Use F3 and Shift+F3 keys to navigate through highlighted usages.
Press Escape to remove highlighting.

Ctrl+W (extend selection) in the editor selects the word at the caret and then selects expanding areas of the source code. For example, it may select a method name, then the expression that calls this method, then the whole statement, then the containing block, etc. You can also select the word at the caret and the expanding areas of the source code by double-clicking the target areas in the editor.

To search through the classes, files, tool windows, actions, settings, and symbols of your project by double pressing the Shift key

Ctrl+P (View | Parameter Info) e.g. localURL = new URL(localUrlString); select localUrlString and press Ctrl + P

Show html documentation tooltips:  CTRL + Q



Comment uncomment single line: CTRL + /

Comment uncomment selected text: CTRL + SHIFT + /

Code completion (Ctrl+Space)

Alt key and mouse pointer dragging for column selection

If nothing is selected in the editor, and you press Ctrl+C, then the whole line at caret is copied to the clipboard.

Ctrl + Delete  delete word from caret to end.

Ctrl + Backspace delete word from caret to start.

Duplicate line: CTRL + D

To compare two directories,or  jar files, select one or both of them in the Project view and press Ctrl+D.

Editor Delete Line: CTRL + Y

Move line UP, DOWN. Select a code fragment and press Ctrl+Shift+Up or Ctrl+Shift+Down.

To open any class or file in the editor at the desired line, press Ctrl+Shift+N (Navigate | File), start typing the name, and choose the one from the suggestion list. Then type the colon (:) and a line number

Ctrl+Shift+Enter to complete a current statement such as if, do-while, try-catch, return (or a method call)

Alt+Enter to invoke a quick fix or intention action, press the right arrow key to reveal the list of additional options.

To quickly review your recent changes to the project: Alt+Shift+C

Code Completion, you can accept the currently highlighted selection in the popup list with the period character (.), comma (,), semicolon (;), space and other characters.

Quickly move between methods in the editor:  Alt+Up and Alt+Down

Ctrl+Shift+J shortcut joins two lines into one and removes unnecessary space to match your code style

Ctrl+Shift+V to choose and insert recent clipboard contents into the text

Inheritance hierarchy for a selected class: Ctrl+H

Right-clicking on a breakpoint marker  you can quickly enable/disable the breakpoint or adjust its properties.

Evaluate the value of any expression while debugging the program, select its text in the editor (you may press a Ctrl+W a few times to efficiently perform this operation) and press Alt+F8.

Quickly evaluate the value of any expression while debugging the program, hold Alt and click this expression to see its value and calculate it, call a method, etc.

You can use the Extract Variable refactoring even on incomplete statements. Just select the necessary block in the editor and press Ctrl+Alt+V.

To open any particular method or field in editor: Ctrl+Alt+Shift+N

Add unimplemented methods: CTRL + I

Override methods: CTRL + O

Format code: CTRL + ALT + L

Show project: ALT + 1

Show logcat: ALT + 6

Hide project - logcat: SHIFT + ESC

Build: CTRL + F9

Build and Run: CTRL + F10

Alt+Shift+F10  access the Run/Debug dropdown on the main toolbar

Collapse all: CTRL + SHIFT + NumPad +

Expand all: CTRL + SHIFT + NumPad -

Alert messagebox toast Android example code | alert-messagebox-toast-android-example-code

Toast in Android application is equivalent of Alert in JavaScript or MessageBox in WinApi.

// Toast android.widget.Toast.makeText(Context context, CharSequence text, int duration)
// public static Toast makeText (Context context, CharSequence text, int duration) 

Toast.makeText(getApplicationContext(), "Hello world!",


Hashtable key value pair add put get pair Java Android example | hashtable-key-value-pair-add-put-get-pair-java-android-example

How add pair of strings to Hashtable, how get pair key value from Hashtable, how split string, basic Java Android example.


import java.util.Enumeration;
import java.util.Hashtable;
public class MainClass {
	public static void main(String[] arg) {
		// english;germany dictionary
		String[] arrayOfString = { "one;eine", "two;zwei", "three;drei" };

	    Hashtable<String, String> hashTable = new Hashtable<String, String>();
	    for(String s: arrayOfString){
	    	String[] array = s.split(";");
	    	String sKey ="", sValue="";
	    	if(array.length > 1){
	    	sKey = array[0]; sValue = array[1];
	    		hashTable.put(sKey, sValue);

	    Enumeration<String> enumer = hashTable.keys();
	    while (enumer.hasMoreElements()) {
	      String keyFromTable = (String) enumer.nextElement();
	      // get Returns the value to which the specified key is mapped, 
	      // or null if this map contains no mapping for the key
	      System.out.println(keyFromTable + " = " + hashTable.get(keyFromTable));

two = zwei
one = eine
three = drei

How update View TextView with timer Android runnable example | how-update-view-textview-with-timer-android-runnable-example

Update TextView by runnable. Handler, runnable, timer Android example.

public class TimerActivity extends Activity {
TextView hTextView;
Button hButton, hButtonStop;
private Handler mHandler = new Handler();
private int nCounter = 0;
    public void onCreate(Bundle savedInstanceState) {
        hTextView = (TextView)findViewById(R.id.idTextView);
        hButton = (Button)findViewById(R.id.idButton);
        hButtonStop = (Button)findViewById(R.id.idButtonStop);
    } // end onCreate

View.OnClickListener mButtonStartListener = new OnClickListener() {
	public void onClick(View v) {
		try {
         //        Parameters
         //        r  The Runnable that will be executed. 
         //        delayMillis  The delay (in milliseconds) until the Runnable will be executed. 
                       mHandler.postDelayed(hMyTimeTask, 1000); // delay 1 second
		} catch (Exception e) {
			// TODO Auto-generated catch block

private Runnable hMyTimeTask = new Runnable() {
	   public void run() {
	    	   hTextView.setText("Hallo from thread counter: " + nCounter);
    View.OnClickListener mButtonStopListener = new OnClickListener() {
    	public void onClick(View v) {


<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="//schemas.android.com/apk/res/android"
<Button android:text="Button" 
 <Button android:layout_width="wrap_content" 


Java Basic Rules | 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));

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

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");
	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){

"); } 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

Editace: 2011-09-29 12:28:40
Počet článků v kategorii: 397

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