IOS学习笔记 给导航栏的返回按钮设置遮罩

1.先设置返回按钮的标题：（文字为空）

self.navigationItem.backBarButtonItem = [[UIBarButtonItem alloc]initWithTitle:@"" style:UIBarButtonItemStylePlain target:nil action:nil];

2.设置遮罩

[self.navigationController.navigationBar setBackIndicatorImage:[[UIImage imageNamed:@"barButtonItemReturn"]imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal]];
    [self.navigationController.navigationBar setBackIndicatorTransitionMaskImage:[[UIImage imageNamed:@"barButtonItemReturn"]imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal]];