偶然的机会发现window的阿里旺旺的登陆效果蛮有意思的，于是就模仿着做了一下打印机吐纸的动画效果
看起来很神奇的东西，实现起来却不难，下面我给大家看下主要的源码。
- (void)createUI{ UIImageView *backimageView=[[UIImageView alloc]init]; backimageView.image =[UIImage imageNamed:@"1.png"]; backimageView.frame = CGRectMake(50, 100, LBSCREEN_WIDTH-100, 30); [self.view addSubview:backimageView]; backView = [[UIView alloc]initWithFrame:CGRectMake(60, 115, LBSCREEN_WIDTH-120, 0)]; backView.layer.cornerRadius = 5; backView.backgroundColor = [UIColor whiteColor]; backView.layer.borderWidth = 1; backView.layer.borderColor = [UIColor blackColor].CGColor; backView.clipsToBounds = YES; [self.view addSubview:backView]; login_btn = [UIButton buttonWithType:UIButtonTypeCustom]; login_btn.frame = CGRectMake(10, 120, LBSCREEN_WIDTH-140, 35); [login_btn setTitle:@"登陆" forState:UIControlStateNormal]; login_btn.backgroundColor = [UIColor lightGrayColor]; login_btn.layer.cornerRadius = 5; login_btn.layer.borderWidth = 1; login_btn.layer.borderColor = [UIColor lightGrayColor].CGColor; [login_btn addTarget:self action:@selector(passwordClick:) forControlEvents:UIControlEventTouchUpInside]; login_btn.clipsToBounds = YES; pass_btn = [UIButton buttonWithType:UIButtonTypeCustom]; pass_btn.frame = CGRectMake(10, 165, LBSCREEN_WIDTH-140, 35); [pass_btn setTitle:@"注册" forState:UIControlStateNormal]; pass_btn.backgroundColor = [UIColor redColor]; [pass_btn addTarget:self action:@selector(passwordClick:) forControlEvents:UIControlEventTouchUpInside]; pass_btn.layer.cornerRadius = 5; pass_btn.layer.borderWidth = 1; pass_btn.layer.borderColor = [UIColor lightGrayColor].CGColor; pass_btn.clipsToBounds = YES; Name_textfield = [[UITextField alloc]initWithFrame:CGRectMake(10, 20, LBSCREEN_WIDTH-140, 40)]; Name_textfield.placeholder = @"帐号"; Name_textfield.borderStyle = UITextBorderStyleRoundedRect; Pass_textfield = [[UITextField alloc]initWithFrame:CGRectMake(10, 70, LBSCREEN_WIDTH-140, 40)]; Pass_textfield.borderStyle = UITextBorderStyleRoundedRect; Pass_textfield.placeholder = @"密码"; //2秒后开始一个持续一分钟的动画 [UIView animateWithDuration:1 delay:2 options:UIViewAnimationOptionBeginFromCurrentState animations:^{ backView.frame=CGRectMake(60, 115, LBSCREEN_WIDTH-120, 210); } completion:^(BOOL finished) { [backView addSubview:Name_textfield]; dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.3 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{ [backView addSubview:Pass_textfield]; dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.3 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{ [backView addSubview:login_btn]; dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.3 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{ [backView addSubview:pass_btn]; }); }); });}];}- (void)passwordClick:(UIButton *)sender{NSLog(@"hhhhh...."); }不难看懂吧？主要就用到了一个改变frame的动画，x轴和y轴以及宽不变，改变它的高
下面晒下效果图
(http://allluckly.cn)
源码下载的地址
下载地址:https://github.com/AllLuckly/LBPrinterPaper
