LVGL学习记录：滑块

基础运用

代码

#include 
#include 

/*If you want to use the LVGL examples,
  make sure to install the lv_examples Arduino library
  and uncomment the following line.
#include 
*/


// #include 

#define LV_USE_LOG 1

TFT_eSPI tft = TFT_eSPI(); /* TFT instance */

/*Change to your screen resolution*/
static const uint32_t screenWidth  = 320;
static const uint32_t screenHeight = 240;

static lv_disp_draw_buf_t draw_buf;
static lv_color_t buf[ screenWidth * 10 ];

static lv_style_t style_btn;
#if LV_USE_LOG != 0
/* Serial debugging */
void my_print( lv_log_level_t level, const char * file, uint32_t line, const char * fn_name, const char * dsc )
{
   Serial.printf( "%s(%s)@%d->%s\r\n", file, fn_name, line, dsc );
   Serial.flush();
}
#endif

/* Display flushing */
void my_disp_flush( lv_disp_drv_t *disp, const lv_area_t *area, lv_color_t *color_p )
{
   uint32_t w = ( area->x2 - area->x1 + 1 );
   uint32_t h = ( area->y2 - area->y1 + 1 );

   tft.startWrite();
   tft.setAddrWindow( area->x1, area->y1, w, h );
   tft.pushColors( ( uint16_t * )&color_p->full, w * h, true );
   tft.endWrite();

   lv_disp_flush_ready( disp );
}

/*Read the touchpad*/
void my_touchpad_read( lv_indev_drv_t * indev_driver, lv_indev_data_t * data )
{
   uint16_t touchX, touchY;

   bool touched = tft.getTouch( &touchX, &touchY, 600 );

   if( !touched )
   {
      data->state = LV_INDEV_STATE_REL;
   }
   else
   {
      data->state = LV_INDEV_STATE_PR;

      /*Set the coordinates*/
      data->point.x = touchX;
      data->point.y = touchY;

      Serial.print( "Data x " );
      Serial.println( touchX );

      Serial.print( "Data y " );
      Serial.println( touchY );
   }
}
/*
static void btn_event_callback(lv_event_t* event)
{
    static uint32_t counter = 1;
 
    lv_obj_t* btn = lv_event_get_target(event); //获取事件对象
    if (btn != NULL)
    {
        lv_obj_t* label = lv_obj_get_child(btn, 0); // 获取第一个子对象
        if (label != NULL)
        {
            lv_label_set_text_fmt(label, "%d", counter); //设置显示内容
            counter++;
        }
    }
}
 
 
void lv_button_click_event_test()
{
    lv_obj_t* btn = lv_btn_create(lv_scr_act()); // 创建Button对象
    if (btn != NULL)
    {
        lv_obj_add_style(btn, &style_btn, LV_STATE_DEFAULT); // 给按钮对象添加默认样式
        lv_style_set_bg_color(&style_btn, lv_palette_main(LV_PALETTE_YELLOW)); // 样式背景色为黄色
        lv_obj_set_style_radius(btn, LV_RADIUS_CIRCLE, 0);  // 添加按钮对象的圆角弧度样
        lv_obj_set_size(btn, 100, 50); // 设置对象大小,宽度和高度
        lv_obj_set_pos(btn, 110, 100);; // 设置按钮位置，即X和Y坐标
        lv_obj_add_event_cb(btn, btn_event_callback, LV_EVENT_CLICKED, NULL); // 给对象添加CLICK事件和事件处理回调函数
 
        lv_obj_t* label = lv_label_create(btn); // 基于Button对象创建Label对象
        if (label != NULL)
        {
            lv_label_set_text(label, "Click me!"); // 设置显示内容
            lv_obj_center(label); // 对象居中显示
        }
    }
}*/

static void slider_event_callback(lv_event_t* event)
{
    lv_obj_t * slider = lv_event_get_target(event);
    if (slider != NULL)
    {
        lv_obj_t* label = (lv_obj_t* )lv_event_get_user_data(event);
        if (label != NULL)
        {
            // 刷新label对象的文本
            lv_label_set_text_fmt(label, "%d", lv_slider_get_value(slider));
            lv_obj_align_to(label, slider, LV_ALIGN_OUT_TOP_MID, 0, -15);  // 设置对齐，label对象在slider对象上方中间位置
        }
    }
}
 
 
void lv_slider_test()
{
    lv_obj_t * slider = lv_slider_create(lv_scr_act()); // 创建滑块对象
    if (slider != NULL)
    {
        lv_obj_set_width(slider, 200); // 设置slider的宽度
        lv_obj_center(slider);  // 对样显示在屏幕中央
        lv_slider_set_range(slider, 0, 1024); // 设置滑块值的变化范围0-1024
 
        lv_obj_t* label = lv_label_create(lv_scr_act()); // 创建一个标签，用于显示滑块的滑动值
        if (label != NULL)
        {
            lv_label_set_text_fmt(label, "%d", lv_slider_get_min_value(slider)); // 标签默认显示滑块的最小值
            lv_obj_align_to(label, slider, LV_ALIGN_OUT_TOP_MID, 0, -15);  // 标签对象放在slider对象的上方中间位置
 
            // 添加滑块值变化事件和事件回调函数，并将label对象最为事件的user_data
            lv_obj_add_event_cb(slider, slider_event_callback, LV_EVENT_VALUE_CHANGED, (void *)label);
        }
    }
}

void setup()
{
   Serial.begin( 115200 ); /* prepare for possible serial debug */
   Serial.println( "Hello Arduino! (V8.0.X)" );
   Serial.println( "I am LVGL_Arduino" );

   lv_init();

#if LV_USE_LOG != 0
   // lv_log_register_print_cb( my_print ); /* register print function for debugging */
#endif

   tft.begin();          /* TFT init */
   tft.setRotation( 1 ); /* Landscape orientation, flipped */

   /*Set the touchscreen calibration data,
     the actual data for your display can be aquired using
     the Generic -> Touch_calibrate example from the TFT_eSPI library*/
  uint16_t calData[5] = { 442, 3414, 336, 3425, 3 };
  tft.setTouch(calData);

   lv_disp_draw_buf_init( &draw_buf, buf, NULL, screenWidth * 10 );

   /*Initialize the display*/
   static lv_disp_drv_t disp_drv;
   lv_disp_drv_init( &disp_drv );
   /*Change the following line to your display resolution*/
   disp_drv.hor_res = screenWidth;
   disp_drv.ver_res = screenHeight;
   disp_drv.flush_cb = my_disp_flush;
   disp_drv.draw_buf = &draw_buf;
   lv_disp_drv_register( &disp_drv );

   /*Initialize the (dummy) input device driver*/
   static lv_indev_drv_t indev_drv;
   lv_indev_drv_init( &indev_drv );
   indev_drv.type = LV_INDEV_TYPE_POINTER;
   indev_drv.read_cb = my_touchpad_read;
   lv_indev_drv_register( &indev_drv );

#if 0
   /* Create simple label */
   lv_obj_t *label = lv_label_create( lv_scr_act() );
   lv_label_set_text( label, "Hello Arduino! (V8.0.X)" );
   lv_obj_align( label, LV_ALIGN_CENTER, 0, 0 );
#else

//   lv_button_click_event_test();
   lv_slider_test();
   /* Try an example from the lv_examples Arduino library
      make sure to include it as written above.
   lv_example_btn_1();
   */

   // uncomment one of these demos
   // lv_demo_widgets();            // OK
   // lv_demo_benchmark();          // OK
   // lv_demo_keypad_encoder();     // works, but I haven't an encoder
   // lv_demo_music();              // NOK
   // lv_demo_printer();
   // lv_demo_stress();             // seems to be OK
#endif
   Serial.println( "Setup done" );
}

void loop()
{
   lv_timer_handler(); /* let the GUI do its work */
   lv_tick_inc(5);
   delay(5);
}

其中最重要的是这三句

lv_obj_set_width(slider, 200); // 设置slider的宽度
lv_obj_center(slider);  // 对样显示在屏幕中央
lv_slider_set_range(slider, 0, 1024); // 设置滑块值的变化范围0-1024

效果