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iOS 生成本地验证码详解

admin 2018年06月21日 手机开发 429 0

在应用程序注册、登陆或者有关支付确认的界面,经常会用到验证码,验证码有的是通过手机发送获取的,有的是在本地点击获取的,通过手机发送获取的动态验证码可以使用第三方类库实现,本地点击获取的是在本地自己绘制的,下面我们来详细讲解一下本地生成动态验证码的过程。

IOS 生成本地验证码

导入CoreGraphics.framework

IOS 生成本地验证码

IOS 生成本地验证码

验证码封装了一个UIView,在使用的时候直接把这个View加到界面上使用

CaptchaView.h

#import <UIKit/UIKit.h> 
 
@interface CaptchaView : UIView 
 
@property (nonatomic, retain) NSArray *changeArray; //字符素材数组 
@property (nonatomic, retain) NSMutableString *changeString;  //验证码的字符串 
 
@end

CaptchaView.m

#import "CaptchaView.h" 
 
#define kRandomColor  [UIColor colorWithRed:arc4random() % 256 / 256.0 green:arc4random() % 256 / 256.0 blue:arc4random() % 256 / 256.0 alpha:1.0]; 
#define kLineCount 6 
#define kLineWidth 1.0 
#define kCharCount 6 
#define kFontSize [UIFont systemFontOfSize:arc4random() % 5 + 15] 
 
@implementation CaptchaView 
@synthesize changeString,changeArray; 
 
- (instancetype)initWithFrame:(CGRect)frame 
{ 
    if (self = [super initWithFrame:frame]) { 
 
        self.layer.cornerRadius = 5.0; //设置layer圆角半径 
        self.layer.masksToBounds = YES; //隐藏边界 
        self.backgroundColor = kRandomColor; 
 
        //显示一个随机验证码 
        [self changeCaptcha]; 
    } 
 
    return self; 
} 
#pragma mark 更换验证码,得到更换的验证码的字符串 
-(void)changeCaptcha 
{ 
//<一>从字符数组中随机抽取相应数量的字符,组成验证码字符串 
    //数组中存放的是全部可选的字符,可以是字母,也可以是中文 
    self.changeArray = [[NSArray alloc] initWithObjects:@"0",@"1",@"2",@"3",@"4",@"5",@"6",@"7",@"8",@"9",@"A",@"B",@"C",@"D",@"E",@"F",@"G",@"H",@"I",@"J",@"K",@"L",@"M",@"N",@"O",@"P",@"Q",@"R",@"S",@"T",@"U",@"V",@"W",@"X",@"Y",@"Z",@"a",@"b",@"c",@"d",@"e",@"f",@"g",@"h",@"i",@"j",@"k",@"l",@"m",@"n",@"o",@"p",@"q",@"r",@"s",@"t",@"u",@"v",@"w",@"x",@"y",@"z",@"杰",@"瑞",@"教",@"育",nil]; 
 
    //如果能确定最大需要的容量,使用initWithCapacity:来设置,好处是当元素个数不超过容量时,添加元素不需要重新分配内存 
    NSMutableString *getStr = [[NSMutableString alloc] initWithCapacity:kCharCount]; 
    self.changeString = [[NSMutableString alloc] initWithCapacity:kCharCount]; 
 
    //随机从数组中选取需要个数的字符,然后拼接为一个字符串 
    for(int i = 0; i < kCharCount; i++) 
    { 
        NSInteger index = arc4random() % ([self.changeArray count] - 1); 
        getStr = [self.changeArray objectAtIndex:index]; 
 
        self.changeString = (NSMutableString *)[self.changeString stringByAppendingString:getStr]; 
    } 
 
//<2>从网络获取字符串,然后把得到的字符串在本地绘制出来(网络获取步骤在这省略) 
//    self.changeString = [NSMutableString stringWithString:@"杰瑞教育"]; 
} 
 
#pragma mark 点击view时调用,因为当前类自身就是UIView,点击更换验证码可以直接写到这个方法中,不用再额外添加手势 
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event 
{ 
    //点击界面,切换验证码 
    [self changeCaptcha]; 
 
    //setNeedsDisplay调用drawRect方法来实现view的绘制 
    [self setNeedsDisplay]; 
} 
 
#pragma mark 绘制界面(1.UIView初始化后自动调用; 2.调用setNeedsDisplay方法时会自动调用) 
- (void)drawRect:(CGRect)rect { 
    // 重写父类方法,首先要调用父类的方法 
    [super drawRect:rect]; 
 
    //设置随机背景颜色 
    self.backgroundColor = kRandomColor; 
 
    //获得要显示验证码字符串,根据长度,计算每个字符显示的大概位置 
    NSString *text = [NSString stringWithFormat:@"%@",self.changeString]; 
    CGSize cSize = [@"S" sizeWithAttributes:@{NSFontAttributeName:[UIFont systemFontOfSize:20]}]; int width = rect.size.width / text.length - cSize.width; 
    int height = rect.size.height - cSize.height; 
    CGPoint point; 
 
    //依次绘制每一个字符,可以设置显示的每个字符的字体大小、颜色、样式等 
    float pX, pY; 
    for (int i = 0; i < text.length; i++) 
    { 
        pX = arc4random() % width + rect.size.width / text.length * i; 
        pY = arc4random() % height; 
        point = CGPointMake(pX, pY); 
        unichar c = [text characterAtIndex:i]; 
        NSString *textC = [NSString stringWithFormat:@"%C", c]; 
 
        [textC drawAtPoint:point withAttributes:@{NSFontAttributeName:kFontSize}]; 
    } 
 
    //调用drawRect:之前,系统会向栈中压入一个CGContextRef,调用UIGraphicsGetCurrentContext()会取栈顶的CGContextRef 
    CGContextRef context = UIGraphicsGetCurrentContext(); 
    //设置画线宽度 
    CGContextSetLineWidth(context, kLineWidth); 
 
    //绘制干扰的彩色直线 
    for(int i = 0; i < kLineCount; i++) 
    { 
        //设置线的随机颜色 
        UIColor *color = kRandomColor; 
        CGContextSetStrokeColorWithColor(context, [color CGColor]); 
        //设置线的起点 
        pX = arc4random() % (int)rect.size.width; 
        pY = arc4random() % (int)rect.size.height; 
        CGContextMoveToPoint(context, pX, pY); 
        //设置线终点 
        pX = arc4random() % (int)rect.size.width; 
        pY = arc4random() % (int)rect.size.height; 
        CGContextAddLineToPoint(context, pX, pY); 
        //画线 
        CGContextStrokePath(context); 
    } 
} 
 
@end

<三>在界面上添加验证码

ViewController.m

#import "ViewController.h" 
#import "CaptchaView.h" 
 
@interface ViewController ()<UITextFieldDelegate,UIAlertViewDelegate> 
{ 
    CaptchaView *_captchaView; 
    UITextField *_input; 
} 
 
@end 
 
@implementation ViewController 
 
- (void)viewDidLoad { 
    [super viewDidLoad]; 
 
    //显示验证码界面 
    _captchaView = [[CaptchaView alloc] initWithFrame:CGRectMake(20, 40, 150, 40)]; 
    [self.view addSubview:_captchaView]; 
 
    //提示文字 
    UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(190, 40, 100, 40)]; 
    label.text = @"点击图片换验证码"; 
    label.font = [UIFont systemFontOfSize:12]; 
    label.textColor = [UIColor grayColor]; 
    [self.view addSubview:label]; 
 
    //添加输入框 
    _input = [[UITextField alloc] initWithFrame:CGRectMake(20, 100, 150, 40)]; 
    _input.layer.borderColor = [UIColor lightGrayColor].CGColor; 
    _input.layer.borderWidth = 2.0; 
    _input.layer.cornerRadius = 5.0; 
    _input.font = [UIFont systemFontOfSize:21]; 
    _input.placeholder = @"请输入验证码!"; 
    _input.clearButtonMode = UITextFieldViewModeWhileEditing; 
    _input.backgroundColor = [UIColor clearColor]; 
    _input.textAlignment = NSTextAlignmentCenter; 
    _input.returnKeyType = UIReturnKeyDone; 
    _input.delegate = self; 
    [self.view addSubview:_input]; 
} 
 
#pragma mark 输入框协议中方法,点击return按钮 
- (BOOL)textFieldShouldReturn:(UITextField *)textField 
{ 
    //判断输入的是否为验证图片显示的验证码 
    if ([_input.text isEqualToString:_captchaView.changeString]) { 
        //正确弹出警告款提示正确 
        UIAlertView *alview = [[UIAlertView alloc] initWithTitle:@"恭喜您 ^o^" message:@"验证成功" delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil, nil]; 
        [alview show]; 
    } 
    else 
    { 
        //验证不匹配,验证码和输入框晃动 
        CAKeyframeAnimation *anim = [CAKeyframeAnimation animationWithKeyPath:@"transform.translation.x"]; 
        anim.repeatCount = 1; 
        anim.values = @[@-20, @20, @-20]; 
        [_captchaView.layer addAnimation:anim forKey:nil]; 
        [_input.layer addAnimation:anim forKey:nil]; 
    } 
    return YES; 
} 
 
#pragma mark 警告框中方法 
-(void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex 
{ 
    //清空输入框内容,收回键盘 
    if (buttonIndex==0) { 
        _input.text = @""; 
        [_input resignFirstResponder]; 
    } 
} 
@end
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