ExtJs 5 Dynamic Grid pagination - extjs

Question

I am creating a dynamic grid (should be paginated) using the data from a POST rest request to server (code below). I am passing the pageid and pagesize to the server during the first request (on load) and it responds back with the appropriate data. I have docked a paging toolbar to grid and now I want to enable pagination on click of next, last etc of the pager. How do I POST a request to server and get back the appropriate data back to reconfigure the grid with the next page's data?
var screenResults = {};
screenResults.pageid =1;
screenResults.pagesize = 10;
screenResults = Ext.JSON.encode(screenResults);
Ext.Ajax.request({
url : 'http://localhost/service/getGridData',
method : 'POST',
timeout: 5000000,
scope: this,
dataType: 'json',
jsonData: screenResults,
success: function(response){
var grid = Ext.getCmp("idSearchResultsGrid");
var gridData = Ext.decode(response.responseText);
var fields = gridData.data.fields;
var newColumns = gridData.data.columns;
var arr = gridData.data.data;
var data = [];
for(var i=0;i<arr.length;i++){
var obj = arr[i].resultsMap;
data.push(obj);
}
var newStore = Ext.create('Ext.data.Store', {
storeId: 'DynamicGridStore',
pageSize:10,
fields: fields,
data: data
/*
proxy: {
type: 'ajax',
url : 'http://localhost/service/getGridData',
method : 'POST',
timeout: 5000000,
jsonData: screenResults,
actionMethods: {
read : 'POST'
}
}
*/
});
//debugger;
/*
globalStore = newStore.load({
params: {
start: 0,
limit: 10
}
});
*/
var pagingBar = Ext.create('Ext.PagingToolbar', {
pageSize: 10,
store: newStore,
dock: 'bottom',
displayInfo: true
});
grid.removeDocked(grid.getDockedItems()[1]);
grid.addDocked(pagingBar);
grid.reconfigure(newStore, newColumns);
},
failure: function(response){
console.log(response);
}
});
},

Answer 1

First of all, you don't need to explicitly do AJAX calls like that. They will be done for you behind the scenes by the store's proxy — provided that the proxy is properly configured (yours is commented out at the moment).
Your task is very trivial and covered by multiple examples. Have a look at this one. Click on Details on the right hand side to see the code.
Also see Ext.toolbar.Paging documentation.