ExtJs:Initializing a global variable

问题

I have a global variable which needs to be initialized when the store is loaded and needs to use that value in another store as follows

var cp = 0;

Ext.onReady(function() {
    Ext.define('Init', {
        singleton: true,
        cp: 0
    });

    Ext.define('loggedUserList', {
        extend: 'Ext.data.Model',
        fields: [
            'id',
            'name'
        ]
    });

    loggedUser = Ext.create('Ext.data.Store', {
        model: 'loggedUserList',
        autoLoad: true,
        proxy: {
        type: 'ajax',
        url: url+'/lochweb/loch/users/getLoggedUser',
        reader: {
            type: 'json',
            root: 'provider'
        },
        listeners: {
            load: function(loggedUser) {
                Init.cp = loggedUser.getAt(0).data.id;
            }
        }
    }); 
});

I am using the value of cp in another url as follows: url: url + '/lochweb/loch/vocabulary/getVocabularyByProvider?providerId=' + Init.cp,

Ext.define('vocbList', {
    extend: 'Ext.data.Model',
    fields: [
        {
            name: 'id',
            mapping: 'id'
        },
        {
            name: 'code',
            mapping: 'code'
        }
    ]
});

var vocabulary = Ext.create('Ext.data.Store', {             
    model: 'vocbList',
    autoLoad: true,
    proxy: {
        type: 'ajax',                   
        url: url+'/lochweb/loch/vocabulary/getVocabularyByProvider?providerId='+Init.cp,                    
        reader: {
            type: 'json',
            root: 'Vocabulary'
        }
    }
});

but its value is still 0. I tried using(cp, Init.cp). How to assign its value form store so that it can be reused?

Thanks

回答1:

Store loads data asynchronously, so you can't be sure that Init.cp will be initialized with a new value before the other store is been loaded. Try with this:

var cp=0;

Ext.onReady(function(){
Ext.define('Init', {
    singleton: true,
    cp: 0
});

Ext.define('vocbList', {
            extend: 'Ext.data.Model',
            fields: [
                { name: 'id', mapping: 'id' },
                { name: 'code', mapping: 'code' }

            ]
        });



    var vocabulary = Ext.create('Ext.data.Store', {             
        model: 'vocbList',
        proxy: {
            type: 'ajax',                                   
            reader:  {
                type: 'json',
                root: 'Vocabulary'
            }
        }

Ext.define('loggedUserList', {
                extend: 'Ext.data.Model',
                fields: ['id','name']
            });

            loggedUser = Ext.create('Ext.data.Store', {
                model: 'loggedUserList',
                autoLoad: true,
                proxy: {
                    type: 'ajax',
                    url : url+'/lochweb/loch/users/getLoggedUser',
                    reader: {
                     type: 'json',
                        root: 'provider'
                    }                   
                },
                listeners: {
                    load:function(loggedUser){
                        Init.cp = loggedUser.getAt(0).data.id;
                        vocabulary.getProxy().url = url+'/lochweb/loch/vocabulary/getVocabularyByProvider?providerId='+Init.cp;
                        vocabulary.load();
                    }
                }

            }); 
});

As you can see, you have to set the url of the vocabulary proxy dynamically when the first store is just loaded and then load the store.

Cyaz

回答2:

Here you declare loggedUser = Ext.create('Ext.data.Store', { model: 'loggedUserList', autoLoad: true,...} with Init.cp is assigned with some data in load(). But you cannot confirm that Init.cp has actually had value at the time you declare variable vocabulary (i.e. maybe loggedUser has not yet fully been loaded). So it still be 0 in the url.

To confirm, you should move codes of vocbList and vocabulary into a function:

function vocabularyLoad() {
   Ext.define('vocbList', {...});
   var vocabulary = ...
}

and use the function this way in loggedUser:

loggedUser = Ext.create('Ext.data.Store', {
    ...
    listeners: {
         load:function(loggedUser){
              Init.cp = loggedUser.getAt(0).data.id;
              vocabularyLoad();
         }
    }
 });

But actually, this refactoring makes the assignment of Init.cp redundant because you can directly pass the value of loggedUser.getAt(0).data.id into the defined function.

来源：https://stackoverflow.com/questions/10468734/extjsinitializing-a-global-variable