重要步骤

在LVGL移植文档https://docs.lvgl.io/8.3/porting/project.html中， 总共有5个重要步骤：

  1. 调用lv_init() ：lvgl的初始化核心
  2. 初始化我们自己的屏幕驱动相关，I2C,SPI,ST7789,CST816T等
  3. 调用lv_port_disp_init()（负责显示部分） 和 lv_port_indev_init()（负责输入部分）
  4. 调用lv_tick_inc(x) ：这个是负责维持lvgl核心库的心跳
  5. 调用lv_timer_handler()： 负责lvgl中的相关任务

前面1，2，3个步骤都是与初始化相关，我们把它们写在启动任务中

  1. static void start_task() {
  2.     taskENTER_CRITICAL();
  4.     lv_init();
  5.     lv_port_disp_init();
  6.     lv_port_indev_init();
  8.     vTaskDelete(start_handler);
  10.     taskEXIT_CRITICAL();
  11. }

lv_tick_inc(x)

我们需要维持lvgl自身的心跳，以便让它能够处理它自身内部的任务，例如动画的渲染，长按单击事件的判断等等， 我们将这个函数放到FreeRTOS的调用函数中
例如，我们在main.c文件中定义如下名称函数：

  2. void vApplicationTickHook( void ){
  3.     lv_tick_inc(1);
  4. }

注意，定义了这个函数，我们还需要打开它对应的宏，在FreeRTOSConfig.h文件中第57行

  1. #define configUSE_TICK_HOOK    1

lv_timer_handler()

lvgl中的所有的任务处理都在这个函数里，lvgl是线程不安全的，这个函数同时只能有一个线程调用它，保险起见我们需要给它的调用加一把锁

声明一把锁

  1. SemaphoreHandle_t     xMutex;

初始化这把锁

  1. xMutex = xSemaphoreCreateMutex();

创建一个任务

  1. xTaskCreate(lvgl_timer_task, "lvgl_timer_task", 1024, NULL, 4, NULL);

编写任务的内容

  1. void lvgl_timer_task(void * pvParameters)
  2. {
  3.     xMutex = xSemaphoreCreateMutex();
  5.     lv_obj_t * btn2 = lv_btn_create(lv_scr_act());
  6.     lv_obj_set_size(btn2,100,100);
  7.     lv_obj_align(btn2, LV_ALIGN_CENTER, 0, 0);
  8.     lv_obj_add_flag(btn2, LV_OBJ_FLAG_CHECKABLE);
  10.     lv_obj_t * label2 = lv_label_create(btn2);
  11.     lv_label_set_text(label2, "Toggle");
  12.     lv_obj_center(label2);
  14.     while(1)
  15.     {
  16.         if(pdTRUE == xSemaphoreTake(xMutex,portMAX_DELAY))    
  17.         {
  18.             lv_timer_handler();        
  19.             xSemaphoreGive(xMutex);
  20.         }
  21.         vTaskDelay(pdMS_TO_TICKS(1));            
  22.     }
  23. }

创建刷新的任务

  1. static void lvgl_refresh_task() {
  2.         lv_obj_t * label = lv_label_create(lv_scr_act());
  3.         lv_label_set_text(label, "count:");    
  5.         lv_obj_set_style_text_color(label, lv_palette_main(LV_PALETTE_BLUE), 0);
  6.         lv_obj_set_pos(label,10,10);
  7.         int count = 0;
  8.     while(1) {
  10.                 lv_label_set_text_fmt(label,"count:%d",count);
  11.                 count++;
  12.         vTaskDelay(pdMS_TO_TICKS(1000));
  13.                 printf("task1 \r\n");
  14.     }
  15. }

完整示例代码

  1. #include "gd32f4xx.h"
  2. #include "systick.h"
  3. #include <stdio.h>
  4. #include <string.h>
  5. #include "main.h"
  7. #include "bsp_usart.h"
  9. #include "FreeRTOS.h"
  10. #include "task.h"
  11. #include "lvgl.h"
  12. #include "lv_port_disp.h"
  13. #include "lv_port_indev.h"
  14. #include "i2c.h"
  15. #include "st7789.h"
  16. #include "semphr.h"
  18. static TaskHandle_t           start_handler;
  19. static SemaphoreHandle_t     xMutex;
  22. void Usart0_recv(uint8_t *data, uint32_t len) {
  23.     printf("Usart0_recv:%s \r\n",data);
  24. }
  26. static void lvgl_refresh_task() {
  27.         lv_obj_t * label = lv_label_create(lv_scr_act());
  28.         lv_label_set_text(label, "count:");    
  30.         lv_obj_set_style_text_color(label, lv_palette_main(LV_PALETTE_BLUE), 0);
  31.         lv_obj_set_pos(label,10,10);
  32.         int count = 0;
  33.     while(1) {
  35.                 lv_label_set_text_fmt(label,"count:%d",count);
  36.                 count++;
  37.         vTaskDelay(pdMS_TO_TICKS(1000));
  38.                 printf("task1 \r\n");
  39.     }
  40. }
  43. void lvgl_timer_task(void * pvParameters)
  44. {
  45.     xMutex = xSemaphoreCreateMutex();
  47.     lv_obj_t * btn2 = lv_btn_create(lv_scr_act());
  48.     lv_obj_set_size(btn2,100,100);
  49.     lv_obj_align(btn2, LV_ALIGN_CENTER, 0, 0);
  50.     lv_obj_add_flag(btn2, LV_OBJ_FLAG_CHECKABLE);
  52.     lv_obj_t * label2 = lv_label_create(btn2);
  53.     lv_label_set_text(label2, "Toggle");
  54.     lv_obj_center(label2);
  56.     printf("lcd_refresh_tas\r\n");
  58.     while(1)
  59.     {
  60.         if(pdTRUE == xSemaphoreTake(xMutex,portMAX_DELAY))    
  61.         {
  62.             lv_timer_handler();        
  63.             xSemaphoreGive(xMutex);
  64.         }
  65.         vTaskDelay(pdMS_TO_TICKS(1));            
  66.     }
  67. }
  70. static void start_task() {
  71.     taskENTER_CRITICAL();
  73.         bsp_usart_dma_init(115200);
  74.         printf("start123\r\n");
  76.         I2C_init();
  78.         lv_init();
  79.         lv_port_disp_init();
  80.         lv_port_indev_init();
  82.         xTaskCreate(lvgl_timer_task, "lvgl_timer_task", 1024, NULL, 4, NULL);
  83.         xTaskCreate(lvgl_refresh_task, "lvgl_refresh_task", 256, NULL, 4, NULL);
  85.     vTaskDelete(start_handler);
  87.     taskEXIT_CRITICAL();
  88. }
  90. int main(void)
  91. {
  92.     nvic_priority_group_set(NVIC_PRIGROUP_PRE4_SUB0);
  93.     systick_config();
  95.     xTaskCreate(start_task, "start_task", 512, NULL, 1, &start_handler);
  96.     vTaskStartScheduler();
  98.     while(1) {
  99.     }
  100. }
  103. void vApplicationTickHook( void ){
  104.     lv_tick_inc(1);
  105. }