用户登录后，存储用户信息，注销

存储一些用户额外信息到偏好

static NSString * const kKeyUserId = @"id";
static NSString * const kKeyUsername = @"username";
static NSString * const kKeyName = @"name";
static NSString * const kKeyBio = @"bio";
static NSString * const kKeyWeibo = @"weibo";
static NSString * const kKeyBlog = @"blog";
static NSString * const kKeyThemeId = @"theme_id";
static NSString * const kKeyCreatedAt = @"created_at";
static NSString * const kKeyState = @"state";
static NSString * const kKeyPortrait = @"new_portrait";
static NSString * const kKeyEmail = @"email";
static NSString * const kKeyPrivateToken = @"private_token";
static NSString * const kKeyAdmin = @"is_admin";
static NSString * const kKeyCanCreateGroup = @"can_create_group";
static NSString * const kKeyCanCreateProject = @"can_create_project";
static NSString * const kKeyCanCreateTeam = @"can_create_team";
static NSString * const kKeyFollow = @"follow";

@implementation User

+ (void)saveUserInformation:(GLUser *)user {
    NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];
    [userDefaults setFloat:user.userId forKey:kKeyUserId];
    [userDefaults setObject:user.username forKey:kKeyUsername];
    [userDefaults setObject:user.name forKey:kKeyName];
    [userDefaults setObject:user.bio forKey:kKeyBio];
    [userDefaults setObject:user.weibo forKey:kKeyWeibo];
    [userDefaults setObject:user.blog forKey:kKeyBlog];
    [userDefaults setInteger:user.themeId forKey:kKeyThemeId];
    [userDefaults setObject:user.state forKey:kKeyState];
    [userDefaults setObject:user.createdAt forKey:kKeyCreatedAt];
    [userDefaults setObject:user.portrait forKey:kKeyPortrait];
    [userDefaults setObject:user.email forKey:kKeyEmail];
    [userDefaults setObject:user.private_token forKey:kKeyPrivateToken];
    [userDefaults setBool:user.admin forKey:kKeyAdmin];
    [userDefaults setBool:user.canCreateGroup forKey:kKeyCanCreateGroup];
    [userDefaults setBool:user.canCreateProject forKey:kKeyCanCreateProject];
    [userDefaults setBool:user.canCreateTeam forKey:kKeyCanCreateTeam];
    [userDefaults setObject:user.follow forKey:kKeyFollow];
    
    [userDefaults synchronize];
}

通过服务和邮箱来存储密码到钥匙串

+ (void)saveAccount:(NSString *)email andPassword:(NSString *)password {
    [SSKeychain setPassword:password forService:@"Git@OSC" account:email];
}

需要时通过服务和邮箱取出密码

- (void)viewDidAppear:(BOOL)animated
{
    NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];
    NSString *email = [userDefaults objectForKey:@"email"];

    NSString *password = [SSKeychain passwordForService:@"Git@OSC" account:email];
    
    _accountTextField.text = email ?: @"";
    _passwordTextField.text = password ?: @"";
    
    if (!_accountTextField.text.length || !_passwordTextField.text.length) {
        submit.alpha = 0.4;
        submit.enabled = NO;
    }
}

 注销操作，没有删除偏好里的邮箱以及钥匙串里的密码，

#pragma mark - logout
- (void)logout
{
    NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];
    [userDefaults removeObjectForKey:kKeyPrivateToken];
    [userDefaults removeObjectForKey:kKeyUserId];
    [userDefaults removeObjectForKey:kKeyUsername];
    [userDefaults removeObjectForKey:kKeyName];
    [userDefaults removeObjectForKey:kKeyBio];
    [userDefaults removeObjectForKey:kKeyWeibo];
    [userDefaults removeObjectForKey:kKeyBlog];
    [userDefaults removeObjectForKey:kKeyThemeId];
    [userDefaults removeObjectForKey:kKeyState];
    [userDefaults removeObjectForKey:kKeyCreatedAt];
    [userDefaults removeObjectForKey:kKeyPortrait];
    [userDefaults removeObjectForKey:kKeyPrivateToken];
    [userDefaults removeObjectForKey:kKeyAdmin];
    [userDefaults removeObjectForKey:kKeyCanCreateGroup];
    [userDefaults removeObjectForKey:kKeyCanCreateProject];
    [userDefaults removeObjectForKey:kKeyCanCreateTeam];
    [userDefaults removeObjectForKey:kKeyFollow];
    
    // 删除用户动态及项目的缓存
    NSUserDefaults *cache = [NSUserDefaults standardUserDefaults];
    for (int i = 3; i < 6; i++) {
        NSString *key = [NSString stringWithFormat:@"type-%d", i];
        [cache removeObjectForKey:key];
    }
    [cache removeObjectForKey:@"type-9"];
    
    //[self.navigationController popToRootViewControllerAnimated:YES];
    ProjectsViewController *projectViewController = [ProjectsViewController new];
    UINavigationController *front = [[UINavigationController alloc] initWithRootViewController:projectViewController];
    [self.revealController setFrontViewController:front];
    [self.revealController showViewController:self.revealController.frontViewController];

}