在TableView中本身有这条这样的属性
1 | @property(nonatomic, retain) UIColor *sectionIndexBackgroundColor NS_AVAILABLE_IOS(7_0) UI_APPEARANCE_SELECTOR; // the background color of the section index while not being touched |
如果要设置透明，则
1 | tableView.sectionIndexBackgroundColor = [UIColor clearColor]; |