arraylist values on buttons

[d22]

Hi ,

I got a problem. I want to display arratlist values in buttons. ie.there are 9 buttons. I want to display the buttons names from that arraylist. suppose in the list I have 2 4 5 6. I want to diaplay on the button 1 the value 2. on button 2 the value 4. & so on..
But I am getting java.lang.ClassCastException in the line button.setLabel( (String) a); .what should i do.


the code is:-


for (int i=0; i<9; i++) {

button = new Button();
this.add(button);
}
ArrayList arraylist = new ArrayList();

while (true) {
Random random = new Random();
int randomno = random.nextInt( 10);

boolean flag = false;
for (int j = 0; j < (arraylist.size()); j++) {
Integer integer =(Integer) arraylist.get(j);
int randomvalue=integer.intValue();
if (randomvalue == randomno) {

flag = true;
}
}
if (!flag) {

arraylist.add(new Integer(randomno));
}

if (arraylist.size() == 10) {
break;
}
}


for( int j=0,i=0; j<arraylist.size(); j++,i++) {
Object a = arraylist.get(j);

System.out.println("a= " +a);
button.setLabel( (String) a);
System.out.println("List " +arraylist.get(j));
}

}

[hirky]

Change this line: button.setLabel( (String) a);
to: button.setLabel(a.toString());

The problem is casting a which is of type Object to type String.

[Billerg]

try this and let me know if it works; instead of

Object a = arraylist.get(j);
System.out.println("a= " +a);
button.setLabel( (String) a)

try this:

Integer a = (Integer)arraylist.get(j); /**Since you already know the type of object - an Integer*/
System.out.println("a= " +a);
button.setLabel( a.toString() ); /**Returns a String object representing this Integer's value.*/

[Billerg]

hey hirky, you first me

[jagfun]

I'm just curious, why did u put the variable 'i' in your last loop?
for( int j=0,i=0; j<arraylist.size(); j++,i++

[d22]

Hi Billerg

Thanks for the help. Its working fine now. Thanks again

[Billerg]

the reason that happens is that you need to create an array of buttons in order to set the title to each one or do everything in the first "for loop". So what you might end up with is this:

/**
* this is how you declare the button array:
*
* Java.AWT.Button button = new Java.AWT.Button [9];
* Using the 9 array of buttons the code should now read:
*/


for( int j=0,i=0; j<arraylist.size(); j++,i++) {
Object a = arraylist.get(j);

System.out.println("a= " +a);
button[i].setLabel( (String) a);
System.out.println("List " +arraylist.get(j));
}



/**
* also in the first for loop add change the button initialization to the following
**/
button[i] = new Button();

Oh by the way, the code can be cleaned up better (less lines etc) but first get the basics correct.

[Billerg]

@jagfun, is that Mr. Unreal Tournament?

[jagfun]

I think u r only adding text to 1 button. I'll bet it's the last button created that has any text. U need to create an array for ur buttons and add the text u want while traversing the array. I would also suggest using an ordinary integer array instead of an ArrayList just to reduce ur overhead since u already know the number of elements u need. Also u only need one instance of Random so create it outside of the while loop. If u use my suggestions you will have rework ur random number generator code a bit to accomodate the integer array.

Button[] button = new Button[9];
Random random = new Random();
for (int i=0; i<button.length ; i++) {
button[i] = new Button();
this.add(button[i]);
int[] a=new int[button.length];
.
.//random number generator code
.
button[i].setLabel( ""+ a[i]);
}

[jagfun]

yeah I used to be called Mr. Unreal Tournament when I lived in Mobay.