update asserts

examples/widgets/slider/lv_example_slider_2.c

@@ -0,0 +1,43 @@
+#include "../../../lvgl.h"
+#include <stdio.h>
+#if LV_USE_SLIDER
+
+static void slider_event_cb(lv_obj_t * slider, lv_event_t event);
+
+static lv_style_t style_pr;
+static lv_style_t style_def;
+
+/**
+ * Show the current value when the slider if pressed (using only styles).
+ *
+ */
+void lv_example_slider_2(void)
+{
+    lv_style_init(&style_def);
+    lv_style_set_content_opa(&style_def, LV_OPA_TRANSP);
+    lv_style_set_content_align(&style_def, LV_ALIGN_OUT_TOP_MID);
+
+    lv_style_init(&style_pr);
+    lv_style_set_content_opa(&style_pr, LV_OPA_COVER);
+    lv_style_set_content_ofs_y(&style_pr, -15);
+
+    /* Create a slider in the center of the display */
+    lv_obj_t * slider;
+    slider = lv_slider_create(lv_scr_act(), NULL);
+    lv_obj_align(slider, NULL, LV_ALIGN_CENTER, 0, 0);
+    lv_obj_add_event_cb(slider, slider_event_cb, NULL);
+
+    lv_obj_add_style(slider, LV_PART_KNOB, LV_STATE_DEFAULT, &style_def);
+    lv_obj_add_style(slider, LV_PART_KNOB, LV_STATE_PRESSED, &style_pr);
+}
+
+static void slider_event_cb(lv_obj_t * slider, lv_event_t event)
+{
+    if(event == LV_EVENT_VALUE_CHANGED) {
+        static char buf[8];
+        lv_snprintf(buf, sizeof(buf), "%u", lv_slider_get_value(slider));
+        lv_obj_set_style_content_text(slider, LV_PART_KNOB, LV_STATE_DEFAULT, buf);
+    }
+}
+
+#endif