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.

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Další témata ....(Topics)

LayoutLib is too recent. Update your tool Eclipse Android | layoutlib-is-too-recent-update-your-tool-eclipse-android

LayoutLib is too recent. Update your tool!
Eclipse Android Graphical layout resolving problem.

Open in Eclipse menu Help ->Check for Updates

Select updates: [caption id="attachment_593" width="300" caption="Android Eclipse updates dialog"][/caption]

Press Next and update all

Restart Eclipse

layoutlib-is-too-recent-update-your-tool

Timer stopwatch based on Java Calendar class Android example | timer-stopwatch-java-calendar-android-example

Start Stop Stopwatch Timer Android example source code.


private static long mStartTime = 0L;
Calendar cal;
TextView hTextViewVypis = (TextView)findViewById(R.id.idTextVypis);

void start(){
            cal = Calendar.getInstance();
            mStartTime = cal.getTimeInMillis();
}

void stop(){
     prinOutStopWatchTime();
}


    private void prinOutStopWatchTime() {
    	final long start = mStartTime;
    	
    	cal = Calendar.getInstance();
    	long stopTime = cal.getTimeInMillis();
    	long millis = stopTime - start;
    	long milisekundy = millis % 1000;
    	int seconds = (int) (millis / 1000);
    	int minutes = seconds / 60;
    	seconds     = seconds % 60;
    	int hour = minutes / 60;
    	hour = hour % 60;
    	
    	if (seconds < 10) {
    		hTextViewVypis.setText(hour +  ":" + minutes + ":0" + seconds + ":" + milisekundy);
    	} else {
    		hTextViewVypis.setText(hour  +  ":" + minutes + ":" + seconds + ":" + milisekundy);            
    	}
    	
    }

Shuffle List ArrayList Collections Java example | shuffle-list-arraylist-collections-java-example

Add and shuffle elements in LinkedList or ArrayList Java basic example.


import java.util.Collections;
import java.util.LinkedList;
import java.util.List;

public class MainClass {
	public static void main(String[] arg) {
		String[] arrayOfString = {"nothing", "Hello", "people"
				, "bye-bye", "hello", "world!", "End" };
		   List<String> arrayList = new LinkedList<String>();
            for(String s: arrayOfString)
		     arrayList.add(s);

		    Collections.shuffle(arrayList);

		    System.out.println(arrayList);
		    
		  }
}
/*
[hello, world!, bye-bye, nothing, people, End, Hello]
*/

103

Android RadioGroup alignment like TableLayout | android-radiogroup-alignment-like-tablelayout

xml example source code with image.


   <TableLayout android:layout_width="match_parent" android:id="@+id/idTableInRadioGroup" android:layout_height="wrap_content">
        <TableRow android:id="@+id/tableRow1" android:layout_width="wrap_content" android:layout_height="wrap_content">


<RadioGroup android:id="@+id/idRadio_group_1_column"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginLeft="20dp"
            android:orientation="vertical">
 <RadioButton android:id="@+id/idRadio_1"
                android:text="@string/textLabel_1"/>
            <RadioButton android:id="@+id/idRadio_2"
                android:text="@string/textLabel_2"/>
            <RadioButton android:id="@+id/idRadio_3"
                android:text="@string/textLabel_3"/> 
 
        </RadioGroup>
<RadioGroup android:id="@+id/idRadio_group_2_column"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginLeft="20dp"
            android:orientation="vertical">
 
  <RadioButton android:id="@+id/idRadio_4"
                android:text="@string/textLabel_4"/>
            <RadioButton android:id="@+id/idRadio_5"
                android:text="@string/textLabel_5"/>
            <RadioButton android:id="@+id/idRadio_6"
                android:text="@string/textLabel_6"/>
        </RadioGroup>
</TableRow>        
    </TableLayout>

213

Round number float - double to int - long Java example | round-number-float-to-int-java-example


int nf = Math.round(5.789f);
System.out.print(nf); // 6

float f = 28.611f; 
int n3 = Math.round(f);
System.out.println(n3); // 29

double d = 1234.56;
long lon = Math.round(d);
System.out.println(lon); // 1235

int diff = 90 - 40;
// float fDeleni = diff / 10; // error code
float fDeleni = (float)diff / 10.f; // ok
int nRound = Math.round(fDeleni);


// Caution:
int n2 = (int) 8.999f;
System.out.println(n2); // 8

Editace: 2013-12-09 10:54:07
Počet článků v kategorii: 397
Url:random-number-java

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