如设置GRID列排序的时候是
/**//**
* 排序
*/
grid.addListener('sortchange', sortchangeFn);

function sortchangeFn(grid, sortinfo) {
alert('排序'+ sortinfo.field + "方向" + sortinfo.direction);
}

但是就是设置列显示的事件应怎么写？

ColumnModel的
hiddenchange事件

hiddenchange : ( ColumnModel this, Number columnIndex, Boolean hidden )

Fires when a column is hidden or "unhidden".
Listeners will be called with the following arguments:
this : ColumnModel
columnIndex : Number
The column index
hidden : Boolean
true if hidden, false otherwise