临近春节，相信不少app都会加一个新的需求——新年抽奖

不多废话，先上GIF效果图

DEMO链接

1. 跑马灯效果

2. 抽奖效果

实现步骤：

一、跑马灯效果

其实很简单，就是通过以下两张图片，用NSTimer无限替换，达到跑马灯的效果

实现代码：

_rotaryTable = [[UIImageView alloc] initWithFrame:CGRectMake((kScreenWidth-366*XT)/2, 218*XT, 366*XT, 318*XT)];_rotaryTable.tag = 100;[_rotaryTable setImage:[UIImage imageNamed:@"bg_lamp_1"]];[scrollView addSubview:_rotaryTable];_itemBordeTImer = [NSTimer scheduledTimerWithTimeInterval:0.5 target:self selector:@selector(itemBordeTImerEvent) userInfo:nil repeats:YES];[[NSRunLoop currentRunLoop] addTimer:_itemBordeTImer forMode:NSRunLoopCommonModes];- (void)itemBordeTImerEvent{ if (_rotaryTable.tag == 100) { _rotaryTable.tag = 101; [_rotaryTable setImage:[UIImage imageNamed:@"bg_lamp_2"]]; }else if (_rotaryTable.tag == 101){ _rotaryTable.tag = 100; [_rotaryTable setImage:[UIImage imageNamed:@"bg_lamp_1"]]; }}

二、抽奖效果

1.初始化奖品数组，以及按照从上到下，从左到右的顺序布局UI界面

_itemTitleArray = @[@"3跳币",@"嘉年华门票",@"8跳币",@"10朵花",@"128朵花",@"2018跳币",@"528跳币",@"128跳币",@"28朵花",@"88跳币"];for (int i = 0 ; i < 4; i ++) { UIImageView *img = [[UIImageView alloc] initWithFrame:CGRectMake(i*82*XT, 0, 78*XT, 80*XT)]; [img setImage:[UIImage imageNamed:itemImgArray[i]]]; [itemView addSubview:img]; UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(0, 63*XT, 78*XT, 13*XT)]; label.textAlignment = NSTextAlignmentCenter; label.textColor = [UIColor whiteColor]; label.font = [UIFont systemFontOfSize:13*XT]; label.text = _itemTitleArray[I]; [img addSubview:label]; } for (int i = 0 ; i < 2; i ++) { UIImageView *img = [[UIImageView alloc] initWithFrame:CGRectMake(i*(78*XT+169*XT), 84*XT, 78*XT, 80*XT)]; [img setImage:[UIImage imageNamed:itemImgArray[i+4]]]; [itemView addSubview:img]; UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(0, 63*XT, 78*XT, 13*XT)]; label.textAlignment = NSTextAlignmentCenter; label.textColor = [UIColor whiteColor]; label.font = [UIFont systemFontOfSize:13*XT]; label.text = _itemTitleArray[i+4]; [img addSubview:label]; } for (int i = 0 ; i < 4; i ++) { UIImageView *img = [[UIImageView alloc] initWithFrame:CGRectMake(i*82*XT, 168*XT, 78*XT, 80*XT)]; [img setImage:[UIImage imageNamed:itemImgArray[i+6]]]; [itemView addSubview:img]; UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(0, 63*XT, 78*XT, 13*XT)]; label.textAlignment = NSTextAlignmentCenter; label.textColor = [UIColor whiteColor]; label.font = [UIFont systemFontOfSize:13*XT]; label.text = _itemTitleArray[i+6]; [img addSubview:label]; }

2.点击之后开始抽奖按钮后，先快速地将选中框正时针转三圈，再慢速地在一圈之内旋转至中奖位置，请注意是按照正时针的顺序旋转，和UI布局的顺序不一致，如图所示：

- (void)getLotteryInfo{ // 快速旋转计数，在NSTimer的方法下自增到29时结束，代表选中框快速旋转了三圈，结束快速旋转 _fastIndex = 0; // 慢速旋转计数，在NSTimer的方法下自增到下面 _selectedIndex 的数字时，选中框到达中奖位置，结束慢速旋转 _slowIndex = -1; // 中奖位置计数，按照顺时针的顺序，如上图所示，若 _selectedIndex = 9 则获得 9 所在位置的奖品 _selectedIndex = arc4random()%10; // 根据奖品数组，获取中奖信息 if (_selectedIndex<4) { _result = _itemTitleArray[_selectedIndex]; }else if (_selectedIndex == 4){ _result = @"2018跳币"; }else if (_selectedIndex == 5){ _result = @"88跳币"; }else if (_selectedIndex == 6){ _result = @"28朵花"; }else if (_selectedIndex == 7){ _result = @"128跳币"; }else if (_selectedIndex == 8){ _result = @"528跳币"; }else if (_selectedIndex == 9){ _result = @"128朵花"; } _itemBorderView.hidden = NO; // 开启快速旋转，时间间隔为0.1秒 _fastTimer = [NSTimer scheduledTimerWithTimeInterval:0.1 target:self selector:@selector(fastTimerEvent) userInfo:nil repeats:YES]; [[NSRunLoop currentRunLoop] addTimer:_fastTimer forMode:NSRunLoopCommonModes];}

3.NSTimer 快速旋转事件

- (void)fastTimerEvent{ // _fastIndex 自增 _fastIndex = _fastIndex + 1; // 顺时针移动选中框的位置 if (_fastIndex % 10 == 0) { [_itemBorderView setFrame:CGRectMake(-1*XT, -1*XT, 80*XT, 82*XT)]; }else if (_fastIndex % 10 == 1){ [_itemBorderView setFrame:CGRectMake(82*XT-1*XT, -1*XT, 80*XT, 82*XT)]; }else if (_fastIndex % 10 == 2){ [_itemBorderView setFrame:CGRectMake(2*82*XT-1*XT, -1*XT, 80*XT, 82*XT)]; }else if (_fastIndex % 10 == 3){ [_itemBorderView setFrame:CGRectMake(3*82*XT-1*XT, -1*XT, 80*XT, 82*XT)]; }else if (_fastIndex % 10 == 4){ [_itemBorderView setFrame:CGRectMake(3*82*XT-1*XT, 84*XT-1*XT, 80*XT, 82*XT)]; }else if (_fastIndex % 10 == 5){ [_itemBorderView setFrame:CGRectMake(3*82*XT-1*XT, 2*84*XT-1*XT, 80*XT, 82*XT)]; }else if (_fastIndex % 10 == 6){ [_itemBorderView setFrame:CGRectMake(2*82*XT-1*XT, 2*84*XT-1*XT, 80*XT, 82*XT)]; }else if (_fastIndex % 10 == 7){ [_itemBorderView setFrame:CGRectMake(82*XT-1*XT, 2*84*XT-1*XT, 80*XT, 82*XT)]; }else if (_fastIndex % 10 == 8){ [_itemBorderView setFrame:CGRectMake(-1*XT, 2*84*XT-1*XT, 80*XT, 82*XT)]; }else if (_fastIndex % 10 == 9){ [_itemBorderView setFrame:CGRectMake(-1*XT, 84*XT-1*XT, 80*XT, 82*XT)]; } // _fastIndex = 29 时选中框结束快速旋转，开启慢速旋转，时间间隔为0.45秒 if (_fastIndex >= 29) { [_fastTimer invalidate]; _slowTimer = [NSTimer scheduledTimerWithTimeInterval:0.45 target:self selector:@selector(slowTimerEvent) userInfo:nil repeats:YES]; [[NSRunLoop currentRunLoop] addTimer:_slowTimer forMode:NSRunLoopCommonModes]; }}

4.NSTimer 慢速旋转事件

// 慢速移动动画- (void)slowTimerEvent{ // _slowIndex 自增 _slowIndex = _slowIndex + 1; // 顺时针移动转中框的位置 if (_slowIndex % 10 == 0) { [_itemBorderView setFrame:CGRectMake(-1*XT, -1*XT, 80*XT, 82*XT)]; }else if (_slowIndex % 10 == 1){ [_itemBorderView setFrame:CGRectMake(82*XT-1*XT, -1*XT, 80*XT, 82*XT)]; }else if (_slowIndex % 10 == 2){ [_itemBorderView setFrame:CGRectMake(2*82*XT-1*XT, -1*XT, 80*XT, 82*XT)]; }else if (_slowIndex % 10 == 3){ [_itemBorderView setFrame:CGRectMake(3*82*XT-1*XT, -1*XT, 80*XT, 82*XT)]; }else if (_slowIndex % 10 == 4){ [_itemBorderView setFrame:CGRectMake(3*82*XT-1*XT, 84*XT-1*XT, 80*XT, 82*XT)]; }else if (_slowIndex % 10 == 5){ [_itemBorderView setFrame:CGRectMake(3*82*XT-1*XT, 2*84*XT-1*XT, 80*XT, 82*XT)]; }else if (_slowIndex % 10 == 6){ [_itemBorderView setFrame:CGRectMake(2*82*XT-1*XT, 2*84*XT-1*XT, 80*XT, 82*XT)]; }else if (_slowIndex % 10 == 7){ [_itemBorderView setFrame:CGRectMake(82*XT-1*XT, 2*84*XT-1*XT, 80*XT, 82*XT)]; }else if (_slowIndex % 10 == 8){ [_itemBorderView setFrame:CGRectMake(-1*XT, 2*84*XT-1*XT, 80*XT, 82*XT)]; }else if (_slowIndex % 10 == 9){ [_itemBorderView setFrame:CGRectMake(-1*XT, 84*XT-1*XT, 80*XT, 82*XT)]; } // 当 _slowIndex >= _selectedIndex 时选中框结束慢速旋转，开启中奖奖品界面 if (_slowIndex >= _selectedIndex) { [_slowTimer invalidate]; dispatch_time_t delayTime = dispatch_time(DISPATCH_TIME_NOW, (int64_t)(1.5 * NSEC_PER_SEC)); dispatch_after(delayTime, dispatch_get_main_queue(), ^{ self.startButton.userInteractionEnabled = YES; [self showLotteryRlesultView]; }); }}

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。