UIButton 点击后变灰

+(UIButton *)getBlueButtonWithTitle:(NSString *)aTitle{

    UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];

   //要使用系统的变灰，只需设置BackgroundImage即可

    [button setBackgroundImage:[UIImage imageNamed:@"blue.png"] forState:UIControlStateNormal];

    [button setTitle:aTitle forState:UIControlStateNormal];

  //变化后标题的颜色设置需设置状态为UIControlStateHighlighted

    [button setTitleColor:[UIColor lightGrayColor] forState:UIControlStateHighlighted];

    button.layer.cornerRadius = 5;

    button.layer.masksToBounds = YES;

    return button;

}