57.使用Preferences保存用户名和密码

 

注意：如果勾选了Use Size Classes，上图中用于登录的Segue的push就得换成show。 

#import "LXViewController.h"

@interface LXViewController ()
@property (weak, nonatomic) IBOutlet UITextField *account;
@property (weak, nonatomic) IBOutlet UITextField *password;
@property (weak, nonatomic) IBOutlet UIButton *LoginBtn;
- (IBAction)LoginClick;

@end

@implementation LXViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    [self.account addTarget:self action:@selector(textChange) forControlEvents:UIControlEventEditingChanged];
    [self.password addTarget:self action:@selector(textChange) forControlEvents:UIControlEventEditingChanged];
    [self loadUserData];
}

- (void) textChange{
    self.LoginBtn.enabled = self.account.text.length && self.password.text.length;
}

- (IBAction)LoginClick {
    NSString *account = self.account.text;
    NSString *password = self.password.text;
    if (![account isEqualToString:@"lx"]) {
        return;
    }
    if (![password isEqualToString:@"123"]) {
        return;
    }
    [self saveUserData];
    [self.view endEditing:YES];
    [self performSegueWithIdentifier:@"login" sender:nil];
}

- (void)loadUserData{
    NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
    self.account.text = [defaults objectForKey:@"account"];
    self.password.text = [defaults objectForKey:@"password"];
}

- (void)saveUserData{
    NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
    [defaults setObject:self.account.text forKey:@"account"];
    [defaults setObject:self.password.text forKey:@"password"];
    [defaults synchronize];
}

@end