UISlider设置按钮透明

    UISlider *aslider = [[UISlider alloc]initWithFrame:kCR(50, 50, 200, 200)];
    [aslider setValue:0.5];
    [aslider setThumbImage:[UIImage imageNamed:@"ssuibian .png"] forState:UIControlStateNormal];
    [aslider setThumbImage:[UIImage imageNamed:@"ssuibian .png"] forState:UIControlStateHighlighted];
    [self.view addSubview:aslider];

注意 图片是  要背景透明的，大小无所谓！

       图片上啥也没能，就是一张透明的图片；