iOS LoginDemo

//
//  ViewController.m
//  FicowLoginDemo1
//
//  Created by Ficow on 15/11/12.
//  Copyright © 2015年 Ficow. All rights reserved.
//

#import "ViewController.h"

@interface ViewController ()
@property (strong, nonatomic) IBOutlet UITextField *account;
@property (strong, nonatomic) IBOutlet UITextField *password;
@property (strong, nonatomic) IBOutlet UIButton *login;
@property (strong, nonatomic) IBOutlet UIImageView *loginBackground;
@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    
    //Notification监听代码
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(textFieldDidChange)//监听实现的方法
                                                 name:@"emptyInput"
                                               object:nil];
    NSLog(@"Initiated");
}

//实现点击背景隐藏键盘
- (IBAction)backgroundTap:(id)sender{
    //将View的class设为UIControl
    NSLog(@"ViewTapped");
    [[NSNotificationCenter defaultCenter] postNotificationName:@"emptyInput" object:self];
    [self.account resignFirstResponder];
    [self.password resignFirstResponder];
}

//设置键盘的return key为next并跳转到下一个输入框，不要忘了设置return key属性
- (IBAction)nextInput:(id)sender{
    NSLog(@"AccountInputFinished");
    [[NSNotificationCenter defaultCenter] postNotificationName:@"emptyInput" object:self];
    [self.account resignFirstResponder];
    [self.password becomeFirstResponder];
}

//输入结束，跳转到按钮，并点击按钮
- (IBAction)textFieldDoneEditing:(id)sender{
    [[NSNotificationCenter defaultCenter] postNotificationName:@"emptyInput" object:self];
    [sender resignFirstResponder];
//    [self.login sendActionsForControlEvents:UIControlEventTouchUpInside];
    NSLog(@"PasswordInputFinished");
}

- (void)textFieldDidChange
{
    NSLog(@"Notification is valid");
    if (self.account.text.length == 0 || self.password.text.length == 0) {
            self.login.userInteractionEnabled = NO;
            self.login.alpha = 0.5;
            self.loginBackground.alpha = 0.2;
    }
    else{
        self.login.userInteractionEnabled = YES;
        self.login.alpha = 1.0;
        self.loginBackground.alpha = 1.0;
    }
}

//错误警告弹出框
- (void) errorAlert:(id) sender
                   :(NSString *) msg
                   :(NSString *) title{
    
    UIAlertController *controller = [UIAlertController alertControllerWithTitle:title/*警告框的标题*/ message:msg preferredStyle:UIAlertControllerStyleAlert];
    UIAlertAction *cancelAction = [UIAlertAction actionWithTitle:@"确定" /*警告框的确定键*/style:UIAlertActionStyleCancel handler:nil];
    [controller addAction:cancelAction];
    [self presentViewController:controller animated:YES completion:nil];
}


- (IBAction)checkInput:(id)sender{//定义警告视图
    
    NSString *msg = nil;
    NSString *title = nil;
    if([self.account.text isEqualToString:@"admin"] &&[self.password.text isEqualToString:@"1234"]){
        msg = [NSString stringWithFormat:@"登录成功！"];
        title = [NSString stringWithFormat:@"Welcome"];
    }//demo1进行账号密码判空的部分
    else{
        if([self.password.text length] == 0 || [self.account.text length] == 0){
            msg = [NSString stringWithFormat:@"账号/密码不能为空！"];
        }
        else{
            msg = [NSString stringWithFormat:@"账号/密码错误！"];
        }
        title = [NSString stringWithFormat:@"Error"];
    }
    
    [self errorAlert:sender
                     :msg
                     :title];
}




- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end

可以学习一下使用ReactiveCocoa库来做LoginDemo，很好用哦！