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viswada Randomly display records error
HI All,
I have to display 20 questions randomly to vf page , i have 67 records in my object,. some times it's dispaly 20 questons , but some times sit diaplaying less than 20 records, If rand value reaches to 67 it not diapaying lessthan 20 records , wha is ther any alternative to to display random records. my controller is
public class questions2 {
public string answer1{set;get;}
public List<selectOption> selItems {get;set;}
public integer intCount{get;set;}
list<wrapperQuestions> objwraplst = new list<wrapperQuestions>();
list<Questiuons__c> ques=new list<Questiuons__c>();
public questions2()
{
integer serial=0;
Integer count = [SELECT COUNT() FROM Questiuons__c ];
system.debug('$$$$$$$$$$$$$$$'+count);
Integer rand = Math.floor(Math.random() * count).intValue();
system.debug('@@@@@@@@@@@@'+rand);
for(Questiuons__c a :[SELECT id,Question__c,Answers__c,Correctanswer__c FROM Questiuons__c LIMIT 20 OFFSET :rand])
{
System.debug('aaa'+a);
String s = a.Answers__c;
list<string> st =s.split(',');
wrapperQuestions objWrap = new wrapperQuestions();
objWrap.strQuestion = a.Question__c;
objWrap.correctAnswer=a.Correctanswer__c;
//serial=serial
serial=serial+1;
objWrap.intSerial=serial;
selItems = new List<selectOption>();
for(String str:st)
{
selItems.add(new SelectOption(str,str));
objWrap.itemsWrap=selItems;
//objWrap.itemsWrap.add(new SelectOption(str,str));
}
objwraplst.add(objWrap);
}
}
public void saveAnswer()
{
intCount=0;
for(wrapperQuestions objwrap:objwraplst)
{
system.debug('::::::::::::'+objwrap.answer12);
if(objwrap.answer12==objwrap.correctAnswer)
{
intCount++;
}
}
}
public list<wrapperQuestions> getitems1()
{
return objwraplst;
}
public class wrapperQuestions
{
public string strQuestion{get;set;}
public integer intSerial{get;set;}
public List<selectOption> itemsWrap {get;set;}
public string answer12{set;get;}
public string correctAnswer{set;get;}
}
}
anyone can help me
HI Mpann,
Thanks alot, Now its woking
All Answers
I don't think you can use the Select statement to produce a truly randomized list and the OFFSET simply skips over x rows.
I would try to get all questions, put them in a list and randomize that list. Then your visual force page only displays the 20.
Thanks for response ,
My senario is I have 20 records in my Qustions objects, i need to diplay all reocrds in random manner, if i refresh the page i the order of records should be changed , how can we do it please help me
I wrote a little utiltiy class, you can use to randomize a list of sObjects:
public class ObjectRandomizer { public static list<sObject> randomizeList (list<sObject> records){ list <sObject> retList = new list <sObject>(); while (records.size()>0){ retList.add(records.remove(getRandomInt(records.size()))); } return retList; } public static Integer getRandomInt (Integer num){ Double d = math.random() * num; return d.intValue(); } }So your controller needs to retrieve all questions and then call the ObjectRandomzier.randomizeList. When your VF page asks for the list of questions, just return the first 20 of that list.
HI Mpann,
Thanks alot, Now its woking