View Navigator Hide Specific Tab Not TabBar - actionscript-3

Question

I'm trying to figure out whether it is possible to define view navigators and selectively hide some depending on a particular user state?
For example I have two navigator tabs one which is a sign in tab and the other shows a users policy. I only want the policy tab to be visible if the user has signed in:
<s:ViewNavigator id="policyTab" width="100%" height="100%" firstView="views.policy.PoliciesView">
<s:navigationContent>
<s:Button id="policyTabButton" label="Policies" click="tabButton_clickHandler(event)" />
</s:navigationContent>
</s:ViewNavigator>
Sign in tab is navigator:
<s:ViewNavigator id="signInTab" width="100%" height="100%" firstView="views.SignInView">
<s:navigationContent>
<s:Button id="signInTabButton" icon="#Embed('images/lockSmall.png')" click="tabButton_clickHandler(event)" />
</s:navigationContent>
</s:ViewNavigator>
Everything that I've researched points me to hiding the entire tab bar which I don't want to do. I've tried simply calling signInTab.visible = false; but is doesn't work.
Any help would be appreciated.

Answer 1

It is true that you can't hide the contents of a TabbedViewNavigator, but there is another way to adjust the content to hide tabs. Basically you can remove the tab from the TabbedViewNavigator to hide it and re-add it to show it again. I've come up with a very simple example which seems to do what you are asking.
TabbedViewNavTest.mxml:
<?xml version="1.0" encoding="utf-8"?>
<s:TabbedViewNavigatorApplication xmlns:fx="http://ns.adobe.com/mxml/2009"
xmlns:s="library://ns.adobe.com/flex/spark"
applicationDPI="160"
preinitialize="preinitializeHandler(event)">
<fx:Script>
<![CDATA[
import mx.events.FlexEvent;
import views.Tab2View;
private static var app:TabbedViewNavigatorApplication;
public static function adjustTabBar():void {
if(app.navigators.length > 1) {
removeTab2();
} else {
addTab2();
}
}
private static function removeTab2():void {
app.tabbedNavigator.removeItemAt(1);
}
private static function addTab2():void {
var tab2:ViewNavigator = new ViewNavigator();
tab2.label = "Tab2";
tab2.percentWidth = 100;
tab2.percentHeight = 100;
tab2.firstView = Tab2View;
app.tabbedNavigator.addItemAt(tab2, 1);
}
protected function preinitializeHandler(event:FlexEvent):void {
app = this;
}
]]>
</fx:Script>
<s:ViewNavigator id="tab1" label="Tab1" width="100%" height="100%" firstView="views.Tab1View"/>
<s:ViewNavigator id="tab2" label="Tab2" width="100%" height="100%" firstView="views.Tab2View"/>
</s:TabbedViewNavigatorApplication>
Tab1View.mxml:
<?xml version="1.0" encoding="utf-8"?>
<s:View xmlns:fx="http://ns.adobe.com/mxml/2009"
xmlns:s="library://ns.adobe.com/flex/spark"
title="Tab1">
<fx:Script>
<![CDATA[
protected function showHideButton_clickHandler(event:MouseEvent):void {
TabbedViewNavTest.adjustTabBar();
}
]]>
</fx:Script>
<s:Button id="showHideButton" label="Click Me!" click="showHideButton_clickHandler(event)" />
</s:View>
Tab2View is just an empty view that was created when I created the project.
While this should do what you need it to do, I'm wondering if there is a better way to achieve what you are attempting to do. For instance, in the case you originally presented of a login tab which disappears when the user logs in you could have created your application as a generic application with 2 states: notLoggedIn and loggedIn. In the notLoggedIn state you only have a view show that presents the login screen, or have a tabbedViewNavigator show which has the login and policy tabs. In the logged in state, you have a separate tabbedViewNavigator which has only the policy tab or perhaps the other tabs available when a user is logged in. If you want me to create an example of what I mean, let me know and I can do that.