Recepty, články, nápady, programování. Dříve dum-zahrada, finance, internet a know-how.okhelp.cz Pro lepší výsledky hledání používejte i diakritiku.

Random number Java


Generate random number Android Java example source code.

		Random rand = new Random();
		int i = rand.nextInt() % 256; // range -255  +255
		System.out.print(i + "

"); // -184 i = Math.abs(rand.nextInt() % 12); // range 0 +11 System.out.print(i); // 7

// Math.random() start with 0.  e.g. 0.35981234 
int nRan = (int) (Math.random()*10); // 0 - 10

// nextDouble(), nextFloat(), nextInt(), nextLong() returns 0 - 10
import java.util.Random;´

Random r = new Random();
int nRan = r.nextInt(); // 0 - 10
double dRan = r.nextDouble() * 10; // e.g. 7.496285271597397

nextDouble – return 0 - 1
nextFloat – same as double
nextInt –  -2147483648  +2147483647
nextLong –  -922337203685775808  +9223372036854775807
nextGaussian –  0.0 aberation 1.0.

397LW NO topic_id


Další témata ....(Topics)


at java.util.Arrays$ArrayList.get(Arrays.java:75) | at-java-util-arraysarraylist-getarrays-java75

Problem in Android application:

E/AndroidRuntime(416): FATAL EXCEPTION: main
E/AndroidRuntime(416): java.lang.IndexOutOfBoundsException
E/AndroidRuntime(416): 	at java.util.Arrays$ArrayList.get(Arrays.java:75)
E/AndroidRuntime(416): 	at android.widget.ArrayAdapter.getItem(ArrayAdapter.java:298)
E/AndroidRuntime(416): 	at android.widget.ArrayAdapter.createViewFromResource(ArrayAdapter.java:351)
E/AndroidRuntime(416): 	at android.widget.ArrayAdapter.getView(ArrayAdapter.java:323)
E/AndroidRuntime(416): 	at android.widget.Spinner.makeAndAddView(Spinner.java:192)
E/AndroidRuntime(416): 	at android.widget.Spinner.layout(Spinner.java:151)
E/AndroidRuntime(416): 	at android.widget.Spinner.onLayout(Spinner.java:115)

Solution: check code for set and get selection

// Spinner _spin1 contain only  49 items 
// you can set max 48 ( range 0 - 48)
// 50 is IndexOutOfBoundsException

ListView add item click item basic Android example code | listview-add-item-click-item-basic-android-example-code

Definition of ListView in layout main.xml file Android example

<ListView android:id="@+id/idListView"
        android:layout_width="fill_parent" /> 

Code in Main.java ListView example source code Java Android

public class Main extends Activity {
    public void onCreate(Bundle savedInstanceState) {
        ListView mlistView = (ListView) findViewById(R.id.idListView);
        mlistView.setAdapter(new ArrayAdapter<String>(this,
                new String[] {"Game", "Help", "Home site"}));
        mlistView.setOnItemClickListener(new OnItemClickListener() {
            public void onItemClick(AdapterView<?> parent, View view,
                int position, long id) {
              // When clicked, show a toast with the TextView text Game, Help, Home
              Toast.makeText(getApplicationContext(), ((TextView) view).getText(),


Eclipse revert old version Android Development Tools | eclipse-revert-old-version-android-development-tools

If you have trouble with compilation of new project after you make a update of android development tools you can go back to old version of the tools.

    • Open Help > About Eclipse... use the menu > About...

    • Click the "Installation Details" button.

    • Select the "Installation History" tab.

    • Select one of the previous configurations.

    • Click the "Revert" button at the bottom.




Unable to execute dex: Multiple dex files define Eclipse Android | unable-to-execute-dex-multiple-dex-files-define-eclipse-android

Try each step separately:

  1. Restart Eclipse

  2. Clean project and rebuild

  3. Create a new project and try it if the problem persists, if no move copy project to other folder, delete project from workspace , create new project same name and copy java, xml etc. files to new project

  4. Close Eclipse, backup folder c:\Users\myName\workspace\.metadata and delete it. Restart Eclipse try again import project to workspace

  5. Re-installing the Android Developer Tools

  6. Re-installing Eclipse - rename old folder with Android to Android_old, create new folder C:\Program Files\Android and copy new Eclipse with sdk into new folder

  7. Created a new project importing from the file system

  8. Created a new project from subversion


EditText hint not show | edittext-hint-not-show

Try this solution - into xml file add row to EditText tag:


Editace: 2013-12-09 10:54:07
Počet článků v kategorii: 397

11 Share