iOS - UIBarbuttonitem图片是蓝色

• 一行代码搞定

    UIImage *selectedImage=[UIImage imageNamed: @"add2"];
    selectedImage = [selectedImage imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
    UIBarButtonItem * btnAdd = [[UIBarButtonItem alloc] initWithImage:selectedImage style:UIBarButtonItemStylePlain target:self action:@selector(clickAdd)];