How to find out which checkboxes have been selected on the next page in VisualForce?

Question

I have a data table which iterates through a custom object and generates checkboxes. On the second page, I want to determine which of these checkboxes have been selected.

In the VisualForce page:

 Age <apex:inputText value="{!age}" id="age" />
 <apex:dataTable value="{!Areas}" var="a">
      <apex:column >
      <apex:inputCheckbox value="{!a.name}" /> <apex:outputText value="{!a.name}" />
      </apex:column>
  </apex:dataTable>

In the Controller:

 public String age {get; set; }
  public List<Area_Of_Interest__c> getAreas() {
      areas = [select id, name from Area_Of_Interest__c];
      return areas;
  }

On my second page, I can retrieve the value that the user put in the textbox "age" by using {!age}. How Do I retrieve which checkboxes have been checked?

Thank you.

Answer 1

Ok, if you want to handle it with Javascript, use Pavel's method, otherwise use the following to do it via the controller. You must create a wrapper class for whatever you wish to track. I'm not sure how it works, but somehow if you name a boolean variable "selected" in your wrapper class, it is mapped to the checkbox. Below is the code:

So in your Visual force page, do:

<apex:dataTable value="{!Foos}" var="f">
    <apex:column >
        <apex:outputLabel value="{!f.foo.name}" /> <apex:inputCheckbox value="{!f.selected}" />
    </apex:column>
 </apex:dataTable>
 <apex:commandButton action="{!getPage2}" value="go"/>

In your Controller, do the following: 1) Make a Wrapper class with the boolean "selected", which somehow maps to the inputCheckbox selected:

public class wFoo {
    public Foo__c foo {get; set}
    public boolean selected {get; set;}

    public wFoo(Foo__c foo) {
        this.foo = foo;
        selected = false; //If you want all checkboxes initially selected, set this to true
    }
}

2) declare the list variables

public List<wFoo> foos {get; set;}
public List<Foo__c> selectedFoos {get; set;}

3) Define the accessor for the List

public List<wFoo> getFoos() {
    if (foos == null) {
        foos = new List<wFoo>();
        for (Foo__c foo : [select id, name from Foo__c]) {
            foos.add(new wFoo(foo));
        }
    }
    return foos;
}

4) Define the method to process the selected checkboxes and place them in a List for use on another page

public void processSelectedFoos() {
    selectedFoos = new List<Foo__c>();
    for (wFoo foo : getFoos) {
        if (foo.selected = true) {
            selectedFoos.add(foo.foo); // This adds the wrapper wFoo's real Foo__c
        }
    }
}

5) Define the method to return the PageReference to the next page when the submit button is clicked

public PageReference getPage2() {
    processSelectedFoos();
    return Page.Page2;
}