Extensions to Ext.grid.GridPanel to make it easier to do programmatically hook into grid filtering.

GridFilteringExtensions.js

Ext.grid.GridPanel.prototype.getFeatures = function() {
  return this.view.featuresMC;
};

Ext.grid.GridPanel.prototype.getFilters = function() {
  var features = this.getFeatures();
  if (features && features.items) {
    for (var i = 0; i < features.items.length; i++) {
      if (features.items[i].ftype === 'filters') {
        return features.items[i];
      }
    }
  }
};

Ext.grid.GridPanel.prototype.createFilters = function() {
  var filters = this.getFilters();
  if (filters) {
    filters.createFilters();
  }
};

Ext.grid.GridPanel.prototype.filter = function(field, value) {
  var filters = this.getFilters();
  if (!filters || !filters.filters) {
    throw new Error ('Could not filter: no filters defined');
  }
  var filter_items = filters.filters.items;
  var filter;
  for (var i = 0; i < filter_items.length; i++) {
    if (filter_items[i].dataIndex === field) {
      filter = filter_items[i];
    }
  }
  if (!filter) {
    throw new Error ("No matching filter");
  }
  filter.setValue(value);
};