UIButton自定制两种状态的图形

- (void)viewDidLoad

{

    [super viewDidLoad];

    UIButton * btn = [UIButton buttonWithType:UIButtonTypeRoundedRect];

    btn.frame = CGRectMake(50, 50, 60, 60);

    [btn setBackgroundImage:[UIImage imageNamed:@"a"] forState:UIControlStateNormal];

    [btn setBackgroundImage:[UIImage imageNamed:@"b"] forState:UIControlStateHighlighted];

    [btn addTarget:self action:@selector(btnPressed:) forControlEvents:UIControlEventTouchUpInside];

    [self.view addSubview:btn];

}

- (void)btnPressed:(UIButton *)btn

{

    [btn setBackgroundImage:[UIImage imageNamed:@"a"] forState:UIControlStateNormal];

    [btn setBackgroundImage:[UIImage imageNamed:@"b"] forState:UIControlStateHighlighted];

}

在XIB上，在state config那一栏上 选择default和highlighted 去选择不同的背景图 

如果要设置[btn setImage: forState: ]; 则需要设置[btn setHighlighted:YES];