Hi，大家好，欢迎来到STM32之littlevGL课堂，我们在上节课中学习了滑动列表控件(lv_roller)，本节课带大家学习滑动条控件，那么什么是滑动条呢？举个最简单的例子——音量调节，这下大家应该都知道了吧~废话不多说！ 一 有图有真相
像不像你调节音量的时候那个滑动条呢~ 二 代码分析 static lv_obj_t * slider_label;
static void slider_event_cb(lv_obj_t * slider, lv_event_t event)
{
if(event == LV_EVENT_VALUE_CHANGED) {
static char buf[4]; /* max 3 bytes for number plus 1 null terminating byte */
snprintf(buf, 4, "%u", lv_slider_get_value(slider));
lv_label_set_text(slider_label, buf);
}
}
static void slider_test(void)
{
/* Create a slider in the center of the display */
lv_obj_t * slider = lv_slider_create(lv_scr_act(), NULL);
lv_obj_set_width(slider, 200);
lv_obj_align(slider, NULL, LV_ALIGN_CENTER, 0, 0);
lv_obj_set_event_cb(slider, slider_event_cb);
lv_slider_set_range(slider, 0, 100);
/* Create a label below the slider */
slider_label = lv_label_create(lv_scr_act(), NULL);
lv_label_set_text(slider_label, "0");
lv_obj_set_auto_realign(slider_label, true);
lv_obj_align(slider_label, slider, LV_ALIGN_CENTER, 0, 30);
/* Create an informative label */
lv_obj_t * info = lv_label_create(lv_scr_act(), NULL);
lv_label_set_text(info, "Welcome to the slider+label demo!\n"
"Move the slider and see that the label\n"
"updates to match it.");
lv_obj_align(info, NULL, LV_ALIGN_CENTER, 0, -50);
} lv_obj_t * slider = lv_slider_create(lv_scr_act(), NULL);
lv_obj_set_width(slider, 200);
lv_obj_align(slider, NULL, LV_ALIGN_CENTER, 0, 0);
lv_obj_set_event_cb(slider, slider_event_cb);
lv_slider_set_range(slider, 0, 100);lv_slider_get_value(slider) OK，本节课就到这里，大家有没有学会呢？最重要的还是要多实践。下节课我们学习微调框控件(lv_spinbox)，我们下节课再见！ |
