Message box (lv_msgbox)
Overview
Message boxes act as pop-ups. They are built from a content area with a helper to add text, an optional header (which can have a title, a close button, and other buttons), and an optional footer with buttons.
The text will be broken into multiple lines and the height will be set automatically. If the height is set manually, the content will become scrollable.
The message box can be modal (blocking clicks on the rest of the screen) or not modal.
Parts and Styles
The message box is built from other widgets, so you can check these widgets' documentation for details.
Content, header, and footer: lv_obj.h
Buttons: lv_button.h
Title and content text: lv_label.h
Usage
Create a message box
lv_msgbox_create(parent) creates a message box.
If parent is NULL the message box will be modal.
Get the parts
The building blocks of the message box can be obtained using the following functions:
lv_obj_t * lv_msgbox_get_content(lv_obj_t * obj);
lv_obj_t * lv_msgbox_get_title(lv_obj_t * obj);
lv_obj_t * lv_msgbox_get_header(lv_obj_t * obj);
lv_obj_t * lv_msgbox_get_footer(lv_obj_t * obj);
Functions that add something to the message box return the newly added object:
lv_obj_t * lv_msgbox_add_text(lv_obj_t * obj, const char * text);
lv_obj_t * lv_msgbox_add_title(lv_obj_t * obj, const char * title);
lv_obj_t * lv_msgbox_add_close_button(lv_obj_t * obj);
lv_obj_t * lv_msgbox_add_header_button(lv_obj_t * obj, const void * icon);
lv_obj_t * lv_msgbox_add_footer_button(lv_obj_t * obj, const char * text);
Close the message box
lv_msgbox_close(msgbox) closes (deletes) the message box.
lv_msgbox_close_async(msgbox) closes (deletes) the message box
asynchronously. This is useful if you want the message box to close the on
the next call to lv_timer_handler instead of immediately.
Events
No special events are sent by this widget.
Learn more about Events.
Keys
No Keys are processed by the object type.
Learn more about Keys.
Example
Simple Message box
C code
View on GitHub#include "../../lv_examples.h"
#if LV_USE_MSGBOX && LV_BUILD_EXAMPLES
static void event_cb(lv_event_t * e)
{
lv_obj_t * btn = lv_event_get_target(e);
lv_obj_t * label = lv_obj_get_child(btn, 0);
LV_UNUSED(label);
LV_LOG_USER("Button %s clicked", lv_label_get_text(label));
}
void lv_example_msgbox_1(void)
{
lv_obj_t * mbox1 = lv_msgbox_create(NULL);
lv_msgbox_add_title(mbox1, "Hello");
lv_msgbox_add_text(mbox1, "This is a message box with two buttons.");
lv_msgbox_add_close_button(mbox1);
lv_obj_t * btn;
btn = lv_msgbox_add_footer_button(mbox1, "Apply");
lv_obj_add_event_cb(btn, event_cb, LV_EVENT_CLICKED, NULL);
btn = lv_msgbox_add_footer_button(mbox1, "Cancel");
lv_obj_add_event_cb(btn, event_cb, LV_EVENT_CLICKED, NULL);
return;
}
#endif
Scrolling and styled Message box
C code
View on GitHub#include "../../lv_examples.h"
#if LV_USE_MSGBOX && LV_BUILD_EXAMPLES
static void minimize_button_event_cb(lv_event_t * e)
{
lv_obj_t * mbox = (lv_obj_t *) lv_event_get_user_data(e);
lv_obj_add_flag(mbox, LV_OBJ_FLAG_HIDDEN);
}
void lv_example_msgbox_2(void)
{
lv_obj_t * setting = lv_msgbox_create(lv_screen_active());
lv_obj_set_style_clip_corner(setting, true, 0);
/* setting fixed size */
lv_obj_set_size(setting, 300, 200);
/* setting's titlebar/header */
lv_msgbox_add_title(setting, "Setting");
lv_obj_t * minimize_button = lv_msgbox_add_header_button(setting, LV_SYMBOL_MINUS);
lv_obj_add_event_cb(minimize_button, minimize_button_event_cb, LV_EVENT_CLICKED, setting);
lv_msgbox_add_close_button(setting);
/* setting's content*/
lv_obj_t * content = lv_msgbox_get_content(setting);
lv_obj_set_flex_flow(content, LV_FLEX_FLOW_COLUMN);
lv_obj_set_flex_align(content, LV_FLEX_ALIGN_START, LV_FLEX_ALIGN_CENTER, LV_FLEX_ALIGN_CENTER);
lv_obj_set_style_pad_right(content, -1, LV_PART_SCROLLBAR);
lv_obj_t * cont_brightness = lv_obj_create(content);
lv_obj_set_size(cont_brightness, lv_pct(100), LV_SIZE_CONTENT);
lv_obj_set_flex_flow(cont_brightness, LV_FLEX_FLOW_COLUMN);
lv_obj_set_flex_align(cont_brightness, LV_FLEX_ALIGN_CENTER, LV_FLEX_ALIGN_START, LV_FLEX_ALIGN_CENTER);
lv_obj_t * lb_brightness = lv_label_create(cont_brightness);
lv_label_set_text(lb_brightness, "Brightness : ");
lv_obj_t * slider_brightness = lv_slider_create(cont_brightness);
lv_obj_set_width(slider_brightness, lv_pct(100));
lv_slider_set_value(slider_brightness, 50, LV_ANIM_OFF);
lv_obj_t * cont_speed = lv_obj_create(content);
lv_obj_set_size(cont_speed, lv_pct(100), LV_SIZE_CONTENT);
lv_obj_set_flex_flow(cont_speed, LV_FLEX_FLOW_COLUMN);
lv_obj_set_flex_align(cont_speed, LV_FLEX_ALIGN_CENTER, LV_FLEX_ALIGN_START, LV_FLEX_ALIGN_CENTER);
lv_obj_t * lb_speed = lv_label_create(cont_speed);
lv_label_set_text(lb_speed, "Speed : ");
lv_obj_t * slider_speed = lv_slider_create(cont_speed);
lv_obj_set_width(slider_speed, lv_pct(100));
lv_slider_set_value(slider_speed, 80, LV_ANIM_OFF);
/* footer */
lv_obj_t * apply_button = lv_msgbox_add_footer_button(setting, "Apply");
lv_obj_set_flex_grow(apply_button, 1);
lv_obj_t * cancel_button = lv_msgbox_add_footer_button(setting, "Cancel");
lv_obj_set_flex_grow(cancel_button, 1);
lv_obj_t * footer = lv_msgbox_get_footer(setting);
lv_obj_set_style_bg_color(footer, lv_palette_main(LV_PALETTE_INDIGO), 0);
lv_obj_set_style_bg_opa(footer, LV_OPA_100, 0);
}
#endif