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.
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Converting to string: TypedValue{t=0x10/d=0xe a=-1}
- 14
// error
- "18"
// ok
How add item to ArrayList, sort ArrayList, search find index of item in ArrayList, min(), max() Java basic example.
import java.util.ArrayList;
import java.util.Collections;
public class MainClass {
public static void main(String[] arg) {
String[] arrayOfString = {"nothing", "Hello", "people"
, "bye-bye", "hello", "world!", "End" };
ArrayList<String> arrayList = new ArrayList<String>();
for(String s: arrayOfString)
arrayList.add(s);
Collections.sort(arrayList);
// foreach
for (String str: arrayList)
System.out.println(str);
Object objMin = Collections.min(arrayList);
System.out.println("Min is: " + objMin);
Object objMax = Collections.max(arrayList);
System.out.println("Max is: " + objMax);
int index = Collections.binarySearch(arrayList, "people");
System.out.println("Index of people is: " + index);
}
}
/*
End
Hello
bye-bye
hello
nothing
people
world!
Min is: End
Max is: world!
Index of people is: 5
*/
How start certain Activity if user clicked to ListView item
Start Activity from list – launches other activities from list - latest variant!!!!
Game class Game.java game.xml
You have to add class Game to AndroidManifest.xml
Start Activity from list – launches other activities from list - latest variant!!!!
public class Main extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
try {
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();
String sText = ((TextView) view).getText().toString();
Intent intent = null;
if(sText.equals("Game"))
intent = new Intent(getBaseContext(),
Game.class);
//else if(sText.equals("Help")) ..........
if(intent != null)
startActivity(intent);
}
});
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
Game class Game.java game.xml
You have to add class Game to AndroidManifest.xml
<activity android:name=".Game" android:label="GameLabel">
</activity>
package cz.okhelp.listview;
import android.app.Activity;
import android.os.Bundle;
public class Game extends Activity{
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// you have to create game.xml
setContentView(R.layout.game);
}
}
// solution 1
ImageView imageView = (ImageView)findViewById(R.id.myimage);
imageView.setImageDrawable(null);
// or
imageView.setImageResource(0);
// solution 2 hide ImageView
imageView.setVisibility(View.INVISIBLE);
// solution 3 resize ImageView 0, 0
hImageViewSemafor.setLayoutParams(new LinearLayout.LayoutParams(0,0));
Editace: 2013-12-09 10:54:07
Počet článků v kategorii: 396
Url:random-number-java