自定义返回按钮

- (void)createBackBtn{

UIButton * btn = [[UIButton alloc] initWithFrame:CGRectMake(0, 0, 30, 44)];

[btn setTitle:@"back" forState:UIControlStateNormal];

[btn setTitleColor:[UIColor redColor] forState:UIControlStateNormal];

[btn addTarget:self action:@selector(back) forControlEvents:UIControlEventTouchUpInside];

btn.titleEdgeInsets = UIEdgeInsetsMake(0, -10, 0, 0);//调整文字与屏幕的距离

//    btn.backgroundColor = [UIColor blackColor];

self.navigationItem.hidesBackButton = YES;//把系统自带的按钮隐藏

UIBarButtonItem * item = [[UIBarButtonItem alloc] initWithCustomView:btn];

self.navigationItem.leftBarButtonItem = item;

}