Textarea always jumps back to cursor after scrolling

[niklasf]

LVGL version

v9.5.0-95-gebc9c1be0

Platform

Platform independent

What happened?

Try scrolling a textarea with a long text. When releasing touch, it jumps back to the cursor position. So scrolling is not possible and the only way to navigate is with separate clicks to change the cursor position.

Example recording:

scroll-jump.mp4

How to reproduce?

This appears to be a regression after fix(textarea): scroll to position when style changes.

Ending scroll (maybe because it removes LV_STATE_SCROLLED) is also a possible style change, so lv_textarea_scroll_to_cusor_pos() is now called.

Fixed via

--- a/src/widgets/textarea/lv_textarea.c
+++ b/src/widgets/textarea/lv_textarea.c
@@ -928,7 +928,7 @@ static void lv_textarea_event(const lv_obj_class_t * class_p, lv_event_t * e)
     else if(code == LV_EVENT_DRAW_POST) {
         draw_cursor(e);
     }
-    else if(code == LV_EVENT_SIZE_CHANGED || code == LV_EVENT_STYLE_CHANGED) {
+    else if(code == LV_EVENT_SIZE_CHANGED) {
         lv_textarea_t * ta = (lv_textarea_t *)obj;
         lv_textarea_scroll_to_cusor_pos(obj, ta->cursor.pos);
     }

but maybe this reintroduces the bug that #9407 tried to fix? cc @AndreCostaaa

---

Playground with some textareas and buttons to insert/delete text:

lv_obj_t * textarea_l;
lv_obj_t * textarea_c;
lv_obj_t * textarea_r;

static void simple_style(lv_obj_t * obj)
{
    lv_obj_set_style_pad_column(obj, 0, LV_PART_MAIN);
    lv_obj_set_style_pad_all(obj, 5, LV_PART_MAIN);
    lv_obj_set_style_border_side(obj, LV_BORDER_SIDE_NONE, LV_PART_MAIN);
    lv_obj_set_style_radius(obj, 0, LV_PART_MAIN);
}

static void on_append(lv_event_t*)
{
    lv_textarea_add_text(textarea_l, "Lorem ipsum dolor sit amet");
    lv_textarea_add_text(textarea_c, "Lorem ipsum dolor sit amet");
    lv_textarea_add_text(textarea_r, "Lorem ipsum dolor sit amet");
}

static void on_backspace(lv_event_t*)
{
    lv_textarea_delete_char(textarea_l);
    lv_textarea_delete_char(textarea_c);
    lv_textarea_delete_char(textarea_r);
}

void demo()
{
    lv_obj_t * screen = lv_obj_create(NULL);
    lv_obj_set_size(screen, 1024, 600);
    simple_style(screen);

    lv_obj_set_flex_flow(screen, LV_FLEX_FLOW_COLUMN);
    lv_obj_set_flex_align(screen, LV_FLEX_ALIGN_CENTER, LV_FLEX_ALIGN_CENTER, LV_FLEX_ALIGN_CENTER);

    textarea_l = lv_textarea_create(screen);
    lv_textarea_set_one_line(textarea_l, true);
    lv_textarea_set_align(textarea_l, LV_TEXT_ALIGN_LEFT);
    lv_textarea_set_text(textarea_l, "000000");
    lv_obj_set_size(textarea_l, 200, 40);

    textarea_c = lv_textarea_create(screen);
    lv_textarea_set_one_line(textarea_c, true);
    lv_textarea_set_align(textarea_c, LV_TEXT_ALIGN_CENTER);
    lv_textarea_set_text(textarea_c, "000000");
    lv_obj_set_size(textarea_c, 200, 40);

    textarea_r = lv_textarea_create(screen);
    lv_textarea_set_one_line(textarea_r, true);
    lv_textarea_set_align(textarea_r, LV_TEXT_ALIGN_RIGHT);
    lv_textarea_set_text(textarea_r, "000000");
    lv_obj_set_size(textarea_r, 200, 40);

    lv_obj_t * append = lv_button_create(screen);
    lv_obj_add_event_cb(append, on_append, LV_EVENT_CLICKED, nullptr);

    lv_obj_t * backspace = lv_button_create(screen);
    lv_obj_add_event_cb(backspace, on_backspace, LV_EVENT_CLICKED, nullptr);

    lv_screen_load(screen);
}

[AndreCostaaa]

The demo makes it look like a feature, not a bug ! :D

Thank you for raising the issue, i'm looking into it