查看导航器隐藏特定选项卡而非TabBar

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.