UI简易登陆界面

.m中部分代码, 模拟简易的登陆界面

    UIView *labelBackground = [[UIView alloc] initWithFrame:CGRectMake(20, 60, 280, 150)];

    [labelBackground setBackgroundColor:[UIColor lightGrayColor]];

    labelBackground.alpha = 0.35;

    [self.window addSubview:labelBackground];

    labelBackground.layer.cornerRadius = 10;

    

    UILabel *enter = [[UILabel alloc] initWithFrame:CGRectMake(40, 20, 60, 20)];

    [enter setBackgroundColor:[UIColor cyanColor]];

    enter.text = @"账号";

    enter.textAlignment = NSTextAlignmentCenter;

    enter.textColor = [UIColor blackColor];

    enter.alpha = 0.7;

    [labelBackground addSubview:enter];

    

    UILabel *secretCode = [[UILabel alloc] initWithFrame:CGRectMake(40, 50, 60, 20)];

    [secretCode setBackgroundColor:[UIColor cyanColor]];

    secretCode.text = @"密码";

    secretCode.textAlignment = NSTextAlignmentCenter;

    secretCode.textColor = [UIColor blackColor];

    [labelBackground addSubview:secretCode];

    

    UITextField *accountNumber = [[UITextField alloc] initWithFrame:CGRectMake(120, 20, 120, 20)];

    [accountNumber setBackgroundColor:[UIColor cyanColor]];

    accountNumber.placeholder = @"请输入账号";

    accountNumber.textAlignment = NSTextAlignmentCenter;

    accountNumber.font = [UIFont systemFontOfSize:15];

    accountNumber.borderStyle = UITextBorderStyleRoundedRect;

    accountNumber.alpha = 0.7;

    [accountNumber setClearsOnBeginEditing:YES];

    [labelBackground addSubview:accountNumber];

    

    UITextField *code = [[UITextField alloc] initWithFrame:CGRectMake(120, 50, 120, 20)];

    [code setBackgroundColor:[UIColor cyanColor]];

    code.placeholder = @"请输入密码";

    code.textAlignment = NSTextAlignmentCenter;

    code.font = [UIFont systemFontOfSize:15];

    code.borderStyle = UITextBorderStyleRoundedRect;

    [code setClearsOnBeginEditing:YES];

    code.secureTextEntry = YES;

    [labelBackground addSubview:code];

    

    UIButton *exit = [UIButton buttonWithType:UIButtonTypeSystem];

    [exit setTitle:@"取消" forState:UIControlStateNormal];

    [exit setBackgroundColor:[UIColor orangeColor]];

    [exit setFrame:CGRectMake(70, 90, 60, 20)];

    [labelBackground addSubview:exit];

    

    UIButton *Enter = [UIButton buttonWithType:UIButtonTypeSystem];

    [Enter setTitle:@"登录" forState:UIControlStateNormal];

    [Enter setBackgroundColor:[UIColor orangeColor]];

    [Enter setFrame:CGRectMake(150, 90, 60, 20)];

    [labelBackground addSubview:Enter];

    

    [labelBackground release];

    [enter release];

    [secretCode release];

    [code release];