创建style

• 初时style

    static lv_style_t style_indic;
    lv_style_init(&style_indic);

• 设置背景色为淡红色

lv_style_set_bg_color(&style_indic, lv_palette_lighten(LV_PALETTE_RED, 3));

• 设置渐变颜色为红色

lv_style_set_bg_grad_color(&style_indic, lv_palette_main(LV_PALETTE_RED));

• 设置渐变颜色方向为水平方向渐变

 lv_style_set_bg_grad_dir(&style_indic, LV_GRAD_DIR_HOR);

• 初时化按键按下的style

    static lv_style_t style_indic_pr;
    lv_style_init(&style_indic_pr);

• 设置阴影颜色

lv_style_set_shadow_color(&style_indic_pr, lv_palette_main(LV_PALETTE_RED));

• 设置阴影宽度

 lv_style_set_shadow_width(&style_indic_pr, 10);

• 设置阴影伸展部分

lv_style_set_shadow_spread(&style_indic_pr, 3);

• 创建slider对象，添加style,居中显示

    lv_obj_t* obj = lv_slider_create(lv_scr_act());
    lv_obj_add_style(obj, &style_indic, LV_PART_INDICATOR);
    lv_obj_add_style(obj, &style_indic_pr, LV_PART_INDICATOR | LV_STATE_PRESSED);
    lv_slider_set_value(obj, 70, LV_ANIM_OFF);
    lv_obj_center(obj);

完整代码，仅供参考

static void lv_example_style_13(void)
{
    static lv_style_t style_indic;
    lv_style_init(&style_indic);
    lv_style_set_bg_color(&style_indic, lv_palette_lighten(LV_PALETTE_RED, 3));
    lv_style_set_bg_grad_color(&style_indic, lv_palette_main(LV_PALETTE_RED));
    lv_style_set_bg_grad_dir(&style_indic, LV_GRAD_DIR_HOR);
    static lv_style_t style_indic_pr;
    lv_style_init(&style_indic_pr);
    lv_style_set_shadow_color(&style_indic_pr, lv_palette_main(LV_PALETTE_RED));
    lv_style_set_shadow_width(&style_indic_pr, 10);
    lv_style_set_shadow_spread(&style_indic_pr, 3);
    /*Create an object with the new style_pr*/
    lv_obj_t* obj = lv_slider_create(lv_scr_act());
    lv_obj_add_style(obj, &style_indic, LV_PART_INDICATOR);
    lv_obj_add_style(obj, &style_indic_pr, LV_PART_INDICATOR | LV_STATE_PRESSED);
    lv_slider_set_value(obj, 70, LV_ANIM_OFF);
    lv_obj_center(obj);
}

调用lv_example_style_13运行效果

• 修改阴影伸展部分

lv_style_set_shadow_spread(&style_indic_pr, 13);

• 效果图