self.navigationItem.rightBarButt

这里是正确的姿势：

   self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc] initWithImage:[[UIImage imageNamed:@"LSMain_footLastBg"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal] style:UIBarButtonItemStylePlain target:self action:@selector(searchClick)];