导航栏ITEM默认渲染颜色

UIImage * homeSelectImge = [UIImage imageNamed:@"ico_add"];
//第一种解决方法:因为系统默认是将我们选中的图片渲染为蓝色的,所以在这里我们可以将选中的图片设置为初始值,使其不被渲染就可以;这种方法需要我们设置每一个tabBarItem的selectedImage属性,比较繁琐;
homeSelectImge = [homeSelectImge imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
UIBarButtonItem *addbtn = [[UIBarButtonItem alloc] initWithImage:homeSelectImge style:UIBarButtonItemStylePlain target:self action:@selector(addfriends)];
UIBarButtonItem *connectbtn= [[UIBarButtonItem alloc] initWithTitle:@"联系人" style:UIBarButtonItemStylePlain target:nil action:nil];
NSArray *arr=[[NSArray alloc]initWithObjects:addbtn, connectbtn, nil];
self.title=@"消息";
self.navigationItem.rightBarButtonItems=arr;