将按钮长期保持高亮

[_handoutButton setImage: [UIImage imageNamed:IMG_PUBLIC_VideoView_Handout] forState:UIControlStateNormal];
[_handoutButton setImage: [UIImage imageNamed:IMG_PUBLIC_VideoView_Handout_Cancel] forState:UIControlStateSelected];
[_handoutButton addTarget:self action:@selector(handoutButtonAction) forControlEvents:UIControlEventTouchUpInside];

//讲义开关按钮
- (void)handoutButtonAction{
    
    if (self.isOpenHandout) {
        self.isOpenHandout = NO;
        [_handoutButton setSelected:NO];
    }else{
        self.isOpenHandout = YES;
        [_handoutButton setSelected:YES];
    }
}