Sencha ExtJS RESTful grid example confusion - rest

Question

I am very confused by the Sencha documentation for ExtJS. The documentation begins with a Getting Started guide which highlights and illustrates the importance on a suitable structure for the classes and source code of your application. But the provided examples then break all the conventions laid down by the Getting Started guide. Instead of code being broken down into appropriate Model, Store, View, etc. class files the examples are provided as a single file with example source code which is not easily re-usable in separate source files.
I started by following the Portal example (http://docs.sencha.com/ext-js/4-1/#!/example/portal/portal.html) as this is the sort of application I want to create. I wanted to enhance the Portal example and add in a screen which would display a grid and use a RESTful web service as the data backend. I have created the backend I just want to create the front-end. So I looked at the RESTful example (http://docs.sencha.com/ext-js/4-1/#!/example/restful/restful.html)
I have tried to copy the RESTful example into the recommended pattern of seperate classes e.g. Model, Store, View:
Model:
Ext.define('MyLodge.model.Member', {
extend: 'Ext.data.Model',
fields: [
{name: 'name', type: 'string'},
{name: 'email', type: 'string'},
{name: 'href', type: 'string'}
]
});
Store:
Ext.require('MyLodge.model.Member');
Ext.define('MyLodge.store.Members', {
autoLoad: true,
autoSync: true,
model: 'MyLodge.model.Member',
proxy: {
type: 'rest',
url: 'http://localhost:8888/rest/memberapi/members' ,
reader: {
type: 'json',
root: 'data'
},
writer: {
type: 'json'
}
},
listeners: {
write: function(store, operation){
var record = operation.getRecords()[0],
name = Ext.String.capitalize(operation.action),
verb;
if (name == 'Destroy' ) {
record = operation.records[0];
verb = 'Destroyed';
} else {
verb = name + 'd';
}
Ext.example.msg(name, Ext.String.format( "{0} member: {1}", verb, record.getId()));
}
}
});
View:
Ext.define('MyLodge.view.content.MemberGrid', {
extend: 'Ext.grid.Panel',
alias: 'widget.membergrid',
initComponent: function(){
var store = Ext.create('MyLodge.store.Members' );
Ext.apply( this, {
height: this.height,
store: store,
stripeRows: true,
columnLines: true,
columns: [{
id : 'name',
text : 'Name',
flex: 1,
sortable : true,
dataIndex: 'name'
},{
text : 'E-Mail',
width : 150,
sortable : true,
dataIndex: 'email'
},{
text : 'Href',
width : 200,
sortable : true,
dataIndex: 'href'
}],
dockedItems: [{
xtype: 'toolbar',
items: [{
text: 'Add',
iconCls: 'icon-add',
handler: function(){
// empty record
store.insert(0, new MyLodge.model.Member());
rowEditing.startEdit(0, 0);
}
}, '-', {
itemId: 'delete',
text: 'Delete',
iconCls: 'icon-delete',
disabled: true,
handler: function(){
var selection = grid.getView().getSelectionModel().getSelection()[0];
if (selection) {
store.remove(selection);
}
}
}]
}]
});
this.callParent(arguments);
}
});
But I am not sure where to put the code to control the grid row selection and enable the Delete button:
grid.getSelectionModel().on('selectionchange', function(selModel, selections){
grid.down('#delete').setDisabled(selections.length === 0);
});
Also when I press the Add button I get the following error:
Uncaught TypeError: Object [object Object] has no method 'insert'.
Any help would be appreciated.

Answer 1

You are having scoping issues. Basically the variable store is defined only in the initComponent function and therefore of local function scope.
Your handler function has it's own scope. It is firing in the scope of the toolbar button. So if you say this in the handler it would refer to the button. Hence you can say this.up('panel').store - and that gives you the correct reference to the store backing your grid panel.
Another advice is not to implement everything at once. Write a little bit to see if it works and then add to it little by little.

Answer 2

RE: the docs examples, I agree that it's frustrating, but there's not many options. Having a fully-MVC-style implementation of each example would not only be onerous to produce, but would also probably make point of the example get lost in the structure.
RE: your question about the where to "put" the code to control the grid, I would recommend setting up a controller with listeners for the events on the grid in the control() section. This will let you decouple the handling of the events that are fired by your grid from the view itself.