FormController Events

The FormController object provides the following events.

Note: While using the this keyword (for example, this.view) in a FormController event in order to point to the current controller, you must ensure that the function is not a fat arrow function. Because in fat arrow types of function declarations, the this keyword is taken from the parent scope and might not point to the current FormController. For more information on this limitation, click here.

getModel Event

Invoked when the Navigation object retrieves the model for the current FormController object.

Syntax

getModel();

Parameters

None.

Return Values

Returns the model object that is required for the form.

Remarks

Your app does not directly access the FormController object for a form. If your app needs the model associated with the FormController object, it can access the model by retrieving it through an instance of the Navigation object. This event handler retrieves the model that you want it to use for the form.

Example

getModel : function ()
{
    var model = new CustomFormModel();
    return model;
}				

onCreateView Event

Called when the controller is ready to create the view.

Syntax

onCreateView();

Parameters

None.

Return Values

Returns either the file name of the form to use as the view or an instance of the form.

Remarks

Use this method to dynamically select which view to use for the controller when your app has more than one view for a controller. For more information, see Sharing Controllers Between Forms.

Example 1

onCreateView : function ()
{
    return "ViewFileName.js");
}				

Example 2

onCreateView : function ()
{
    // Create an instance of the view to return or 
    // retrieve the instance from somewhere in your 
    // code where you have stored it. In this example,
    // it's saved in a variable called newInstance.
    return (viewInstance);
}			

onDestroy Event

Triggered just before a form is destroyed.

Syntax

onDestroy();

Parameters

None.

Return Values

None

Remarks

Use this event callback handler function to perform cleanup tasks when a form is about to be destroyed.

Example

onDestroy : function ()
{
    this.context = null;
    this.model = null;
}			

onNavigate Event

This event is invoked when you navigate from one form to another. This is a Form Controller event and is used only in VoltMX Reference Architecture-based projects.

Syntax

onNavigate(  
    context,   
    isBackNavigation)

Parameters

context [Object]

A JavaScript object that contains the data that the destination form requires after navigation.

isBackNavigation [Boolean]

This parameter determines whether you have clicked the back button or not. It has the value as true when you click the back button and false when you do not click the back button.

Read/Write

Read + Write

Remarks

To navigate from one form to another, you must create a Navigation Object. This object navigates to the destination form’s controller. The form’s controller in turn displays the view of the form.

This event is useful in the following scenarios:

• To prepare data that the destination form requires after the navigation.
• To pause the navigation if any asynchronous calls are in progress.

Note: The object that is sent as part of the onNavigate Event is accessible for all form lifecycle events.

Example

define({

    onNavigate: function(context, isBackNavigation) {
        this.context = context;
        this.pauseNavigation();
        voltmx.net.invokeServiceAsync(url, this.callback1);
    },

    callback1: function(result) {
        this.resumeNavigation();
    }

});

Platform Availability

Available on all platforms

setModel Event

Invoked while navigating to a new form the model to set the form’s updated model object.

Syntax

setModel(
    model);

Parameters

model

The model object for the new form.

Return Values

None.

Remarks

Use this event callback handler to set a model for the form being navigated to.

Example

setModel : function (model)
{
    this.model = model;
}