奇数行：
横排：
Swift 版本：PPScroll-Swift
使用：
PPScroll *picker = [[PPScroll alloc]initWithFrame:frame]; picker.delegate = self; [self.view addSubview:picker]; - (void)scroll:(PPScroll *)scroll selectedIndexDic:(NSMutableDictionary *)selectedIndexDic;//所有已选择的index - (void)scroll:(PPScroll *)scroll index:(NSInteger)index;//目标行的index
