iOS替换系统返回按钮图标和事件

self.navigationItem.hidesBackButton = YES;

self.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc] initWithImage:[UIImageMake(@"ic_back") imageWithRenderingMode:(UIImageRenderingModeAlwaysOriginal)] style:UIBarButtonItemStyleDone target:self action:@selector(photoList)];

self.navigationItem.leftItemsSupplementBackButton = YES;