Random number Java
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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
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Další témata ....(Topics)
Problem in Android application:
Solution: check code for set and get selection
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
_spin1.setSelection(50);
Definition of ListView in layout main.xml file Android example
Code in Main.java ListView example source code Java Android
<ListView android:id="@+id/idListView"
android:background="#7700CC00"
android:layout_height="wrap_content"
android:layout_width="fill_parent" />
Code in Main.java ListView example source code Java Android
public class Main extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
ListView mlistView = (ListView) findViewById(R.id.idListView);
mlistView.setAdapter(new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1,
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(),
Toast.LENGTH_SHORT).show();
}
});
}
}
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.
Try each step separately:
- Restart Eclipse
- Clean project and rebuild
- 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
- Close Eclipse, backup folder c:\Users\myName\workspace\.metadata and delete it. Restart Eclipse try again import project to workspace
- Re-installing the Android Developer Tools
- 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
- Created a new project importing from the file system
- Created a new project from subversion
Try this solution - into xml file add row to EditText tag:
android:textColorHint="@color/grey"
Editace: 2013-12-09 10:54:07
Počet článků v kategorii: 397
Url:random-number-java
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