模仿支付宝钱包touchID功能(原创)

最近在做个金融项目，对进入应用会有身份验证，之前用的都是手势解锁。现在用过支付宝后，发现指纹解锁挺棒的，所以想尝试换成这个功能，而且ios8也开放了这个API，所以做起来也不难。

先看下效果图。

1、先新建一个UIViewController吧，主要就是解锁界面搭建。

简单来说，就是进入应用时，如果需要验证，就present这个控制器，验证成功就dismiss这个控制器。

代码用了masonry框架，很优秀的autolayout框架，请自行导入。

//
//  BYUseTouchIDViewController.m//
//  Created by Sunny on 15/8/10.
//  Copyright (c) 2015年 byzk. All rights reserved.
//

#import "BYUseTouchIDViewController.h"

@interface BYUseTouchIDViewController ()

@end

@implementation BYUseTouchIDViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    self.view.backgroundColor = [UIColor whiteColor];
    [self setTouchID];
}

- (void)viewDidAppear:(BOOL)animated
{
    [self evaluatePolicy];
}

- (void)setTouchID
{
    UIImageView *contentImage = [[UIImageView alloc] init];
    contentImage.userInteractionEnabled = YES;
    contentImage.contentMode = UIViewContentModeScaleAspectFill;
    contentImage.image = [UIImage imageNamed:@"sky"];
    [self.view addSubview:contentImage];
    
    UIImage *touchIDImg = [UIImage imageNamed:@"touchID"];
    UIButton *button = [[UIButton alloc] init];
    [button setImage:touchIDImg forState:UIControlStateNormal];
    [button addTarget:self action:@selector(evaluatePolicy) forControlEvents:UIControlEventTouchUpInside];
    [contentImage addSubview:button];
    
    UIButton *touchBtn = [[UIButton alloc] init];
    touchBtn.backgroundColor = [UIColor clearColor];
    [touchBtn setTitle:@"点击进行指纹解锁" forState:UIControlStateNormal];
    [touchBtn setTitleColor:BYColor(5, 148, 223) forState:UIControlStateNormal];
    touchBtn.titleLabel.font = [UIFont systemFontOfSize:16];
    [touchBtn addTarget:self action:@selector(evaluatePolicy) forControlEvents:UIControlEventTouchUpInside];
    [contentImage addSubview:touchBtn];
    
    UIButton *loginBtn = [[UIButton alloc] init];
    loginBtn.backgroundColor = [UIColor clearColor];
    [loginBtn setTitle:@"登录其他账户" forState:UIControlStateNormal];
    [loginBtn setTitleColor:BYColor(22, 96, 140) forState:UIControlStateNormal];
    loginBtn.titleLabel.font = [UIFont systemFontOfSize:16];
    [loginBtn addTarget:self action:@selector(loginOther) forControlEvents:UIControlEventTouchUpInside];
    [contentImage addSubview:loginBtn];
    
    [contentImage mas_makeConstraints:^(MASConstraintMaker *make) {
        make.left.mas_equalTo(self.view.mas_left).offset(0);
        make.top.mas_equalTo(self.view.mas_top).offset(0);
        make.right.mas_equalTo(self.view.mas_right).offset(0);
        make.bottom.mas_equalTo(self.view.mas_bottom).offset(0);
    }];
    
    [button mas_makeConstraints:^(MASConstraintMaker *make) {
        make.center.mas_equalTo(contentImage);
        make.size.mas_equalTo(touchIDImg.size);
    }];
    
    [touchBtn mas_makeConstraints:^(MASConstraintMaker *make) {
        make.centerX.mas_equalTo(contentImage.mas_centerX);
        make.top.mas_equalTo(button.mas_bottom).offset(20);
    }];
    
    [loginBtn mas_makeConstraints:^(MASConstraintMaker *make) {
        make.centerX.mas_equalTo(contentImage.mas_centerX);
        make.bottom.mas_equalTo(contentImage.mas_bottom).offset(-20);
    }];
}
//进入解锁
- (void)evaluatePolicy
{
    LAContext *context = [[LAContext alloc] init];

    // show the authentication UI with our reason string
    [context evaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics localizedReason:NSLocalizedString(@"通过Home键验证已有手机指纹", nil) reply:
     ^(BOOL success, NSError *authenticationError) {
         if (success) {
    //解锁成功就dismiss这个控制器
             [self dismissViewControllerAnimated:NO completion:nil];
         }
     }];
}

- (void)loginOther
{
    //登陆其他账户
}

@end

2、然后来到AppDelegate代理

分析一下支付宝的验证模式。当用户打开应用的时候，进行验证。当应用挂入后台，再进入应用，如果这个时间差大于两分钟（我也不能明确几分钟，就当是两分钟吧）进行验证。

所以在AppDelegate.m中进行设置。

先贴出用到的几个工具类方法

//
//  BYTools.m
//
//  Created by Sunny on 15/8/4.
//  Copyright (c) 2015年 byzk. All rights reserved.
//

#import "BYTools.h"

@implementation BYTools

//这个方法用于验证touchID是否可用
+ (BOOL)canEvaluatePolicy
{
    LAContext *context = [[LAContext alloc] init];
    NSError *error;
    BOOL success;
    
    success = [context canEvaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics error:&error];
    
    return success;
}
//这个方法用于获取当前时间戳
+ (long long)getNowTime
{
    UInt64 nowTime = [[NSDate date] timeIntervalSince1970];
    return nowTime;
}

@end

//AppDelegate.m

//这个方法用来保存时间到本地
- (void)saveTime
{
    NSString *nowTime = [NSString stringWithFormat:@"%lld", [BYTools getNowTime]];
    NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];
    [userDefaults setObject:nowTime forKey:@"enterbgTime"];
}

/**
 进入后台
 **/
- (void)applicationDidEnterBackground:(UIApplication *)application
{
    //进入后台时，我们把这个时间保存下来。
    [self saveTime];
}

//显示touchID验证界面
- (void)showTouchID
{
    if ([BYTools canEvaluatePolicy]) {
        BYUseTouchIDViewController *useTouchID = [[BYUseTouchIDViewController alloc] init];
        [self.window.rootViewController presentViewController:useTouchID animated:NO completion:nil];
    }
}

//判断是否需要进行touchID身份验证
- (void)useTouchID
{
    NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];
    NSString *enterbgTime = [userDefaults objectForKey:@"enterbgTime"];
    if (enterbgTime.length != 0) {
        long long bgTime = enterbgTime.longLongValue;
        long long instanceTime = [BYTools getNowTime] - bgTime;
        if (instanceTime > 120) {
            [self saveTime];
            [self showTouchID];
        }
    }
}

//在应用被激活时调用。通常进入应用时，或者从后台进入前台时使用
- (void)applicationDidBecomeActive:(UIApplication *)application
{
    [self useTouchID];
}

//在进入应用时使用验证
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    //保存时间，防止重复调用
    [self saveTime];
    [self showTouchID];
    
}