how to remove view and read children, getChildren

hello ~ i have some question want to ask. how to remove firstView and read children length ,getChildren. I use this construction to code. I have a window(mainWindow), view(mainView), view(firstView) I want to click my button can execute remove all elements on firstView(firstView have to removed,too). the button is on the firstView, but I can't remove firstView and not read children length,getChildren on the firstView. hot to fix can remove firstView and read children on the firstView. thank you very much. this is my code.

-------------app.js--------------

var GVal = new (require('GVal'))(); var appWin = require('ui').Mainwin(GVal);

GVal.MainView.add(require('ui').firstView(GVal)); appWin.open();

Ti.App.addEventListener('clearFirstViewAddOtherView', function(e){

     //  can't read
Ti.API.info('CreateLoginView view :'+ require('ui').firstView.children.length );
Ti.API.info('CreateLoginView view :'+ require('ui').firstView.getChildren() );

    //  can't remove firstView  ,why?
Val.MainView.remove(require('ui').firstView);

})

-----------app.js end----------

-------------GVal.js--------------

function GVal(){ this.MainView = undefined; this.firstView = undefined;

} module.exports = GVal;

------------GVal.js end----------

----------------ui.js------------------

function Mainwin(GVal){ var win = Ti.UI.createWindow( { title:'test', backgroundColor:'#fff', navBarHidden: true } );

var view = Ti.UI.createView(
    {
        height: 340,
        width: 270,
        left: 20 ,
        top: 50,
        backgroundColor: '#ccc',
        borderWidth: 1
    }
);
win.add(view);
GVal.MainView = view;

var label = Ti.UI.createLabel({
    text: "Title Test" ,
    top: 10 ,
    width: view.width ,
    height: 40 , 
    backgroundColor: '#666',
    textAlign: 'center' ,
    font:{ fontSize:25, fontFamily: 'Helvetica Neue' }

});
view.add(label);

return win;

}; exports.Mainwin = Mainwin;

function firstView(GVal){ var view = Ti.UI.createView( { height: 200, width: 220,

        left: 30,
        top:  80,
        backgroundColor: '#fff',
        borderWidth: 1,borderRadius:7
    }
);

var firstViewLabel = Ti.UI.createLabel(
    {
        text: "Here is first View" ,
        top: 20 ,
        width: 130 ,
        height: 60 , 
        backgroundColor: '#fff',
    }
)
view.add(firstViewLabel);

var contentLabel = Ti.UI.createLabel(
    {
        text: "content label balbal" ,
        top: 70 ,
        width: 130 ,
        height: 60 , 
        backgroundColor: '#666',
    }
)
view.add(contentLabel);

var clearBtn = Ti.UI.createButton(
    {
        width: 200, height: 20, left: 10, top: 150,
        title:'clear first view and button'
    }
)
view.add(clearBtn);

clearBtn.addEventListener('click', function(e){
    Ti.App.fireEvent('clearFirstViewAddOtherView');
})

GVal.firstView = view;
return view;

}; exports.firstView = firstView;

------------ui.js end------------

who can help me? have any one know this problem? thank you very much.