ExtJS 4.1 stop grid.Panel from closing

Question

I have I view that extends Ext.grid.Panel and I want to be able to ask the user if he really wants to close the panel after he clicks [X]. I tried with

listeners: {
            beforedestroy: function() {
                               //console.log('In');
                return false;
            }
        },

but obviously it's not that simple. Any ideas on how to prevent the closing of the panel?

Thanks

Leron

P.S.

This is what I get from sencha forums, haven't test it yet:

Ext.create( 'Ext.window.Window', {
    title: 'test',
    width: 200,
    height: 200,
    listeners: {
        beforeclose: function( window ) {
            Ext.Msg.confirm( 'Hey', 'Are you sure you want to close?', function( answer ) {
                if( answer == "yes" ) {
                    window.destroy();
                }
            } );
            return false;
        }
    }
} ).show(); 

Answer 1

beforeclose event should work. No?

Update:

If you want to have some user interaction (i.e. confirmation question or saving data or something like that) it will be a bit tricky...

First, in the constructor of the view do something like this:

this.on('beforeclose', function() { 
   return this.myCloseHandler(function() { this.close(); }, this);
});
this.alreadyAsked = false;

Than create handler:

myCloseHandler: function(callback, scope) {
    if (this.alreadyAsked === false) {
        this.alreadyAsked = true;
        Ext.MessageBox.show({
            msg: 'Are you sure?',
            fn: function(btn) {
               if (btn == 'yes')
                  Ext.callback(callback, scope);
               else 
                  this.alreadyAsked = false;   
            }
        });
        return false;

    }
    return true;   
}

Idea is - you return false immediately but have some flag and condition to go through the same logic without confirmation.

Answer 2

The technique I use is simply to do a window hide rather than the default destroy of the window and add a beforehide event listener. This prevents that all the components in your window that you want to prevent to destroy, are destroyed anyway. The hide event is a quite innocent event to this with. Then the Ext.msg comes, maybe even only on a certain condition. And your response on the break message finished the job. Otherwise no harm done, because false is returned.

var win = Ext.create('Ext.window.Window', {
       .... your window specs ...
       closeAction : 'hide',
       buttons : [{
            text    : 'Close',
            scope   : me,
            handler : function() {
                win.hide(); // not destroy !!! that comes later !!!
            }
        }],
        listeners : {
            scope  : me,
            'beforehide' : function(window) {
                if (some_condition == true) {
                    Ext.Msg.confirm( 'Confirm close of window', 'You really wanna close this window ?', function( answer ) {
                        if( answer == "yes" ) {
                            window.destroy();
                        }
                    });
                    return false;
                }

            },
            'destroy' : function(window) {
                  // do something after the window destruction //
                  alert('Another window smashed');
            }
        }
        ... rest of your window specs
  });

Answer 3

Maybe there is no need in heavy constructions. The following works perfect for me:

beforeclose: function(window) {
    Ext.Msg.confirm("Hey", "Are you sure you want to close?", function(answer) {
        if (answer == "yes") {
            window.events.beforeclose.clearListeners();
            window.close();
        }
    });
    return false;
}