how to get the current display height of viewController's view

[holyen]

i want to get the display height (self.view.bounds.size.height) of current viewController's view but the value is not correct, the value is always more than correct value.(RDVTabBar 's height value), i want a value
except the UINavigationBar's height and RDVTabBar 's height just a display height, how to get it Thanks~