emwin设计三层可触屏切换页面并且主页面显示时间代码

在前面的代码基础上，实现三层可触屏切换页面并且主页面显示时间的代码如下：

#include "GUI.h"
#include "DIALOG.h"
#include "rtc.h"
#include "TOUCH.h"

static WM_HWIN hWin0, hWin1, hWin2; // 三个窗口句柄

static void _cbWin0(WM_MESSAGE * pMsg) {
  switch (pMsg->MsgId) {
    case WM_PAINT: {
      GUI_Clear();
      GUI_SetFont(&GUI_Font24B_ASCII);
      GUI_DispStringAt("Page 0", 40, 40);
      break;
    }
    default:
      WM_DefaultProc(pMsg);
      break;
  }
}

static void _cbWin1(WM_MESSAGE * pMsg) {
  switch (pMsg->MsgId) {
    case WM_PAINT: {
      GUI_Clear();
      GUI_SetFont(&GUI_Font24B_ASCII);
      GUI_DispStringAt("Page 1", 40, 40);
      break;
    }
    default:
      WM_DefaultProc(pMsg);
      break;
  }
}

static void _cbWin2(WM_MESSAGE * pMsg) {
  switch (pMsg->MsgId) {
    case WM_PAINT: {
      GUI_Clear();
      GUI_SetFont(&GUI_Font24B_ASCII);
      GUI_DispStringAt("Page 2", 40, 40);
      break;
    }
    default:
      WM_DefaultProc(pMsg);
      break;
  }
}

void MainTask(void) {
  GUI_Init();
  TOUCH_Init();
  hWin0 = WM_CreateWindow(0, 0, 240, 240, WM_CF_SHOW, _cbWin0, 0);
  hWin1 = WM_CreateWindow(0, 0, 240, 240, WM_CF_HIDE, _cbWin1, 0);
  hWin2 = WM_CreateWindow(0, 0, 240, 240, WM_CF_HIDE, _cbWin2, 0);

  while (1) {
    GUI_PID_STATE touch_state;
    TOUCH_GetState(&touch_state);
    if (touch_state.Pressed) {
      if (touch_state.x < 80) {
        WM_ShowWindow(hWin0);
        WM_HideWindow(hWin1);
        WM_HideWindow(hWin2);
      } else if (touch_state.x < 160) {
        WM_ShowWindow(hWin1);
        WM_HideWindow(hWin0);
        WM_HideWindow(hWin2);
      } else {
        WM_ShowWindow(hWin2);
        WM_HideWindow(hWin0);
        WM_HideWindow(hWin1);
      }
    }

    RTC_TimeTypeDef RTC_TimeStruct;
    RTC_DateTypeDef RTC_DateStruct;
    RTC_GetTime(&RTC_TimeStruct);
    RTC_GetDate(&RTC_DateStruct);
    char time_str[20];
    sprintf(time_str, "%02d:%02d:%02d", RTC_TimeStruct.RTC_Hours, RTC_TimeStruct.RTC_Minutes, RTC_TimeStruct.RTC_Seconds);

    GUI_Clear();
    GUI_SetFont(&GUI_Font24B_ASCII);
    GUI_DispStringAt(time_str, 150, 0);

    GUI_Exec();
    GUI_Delay(100);
  }
}

这段代码在前面的基础上增加了触屏事件处理。使用 `TOUCH_GetState` 函数获取触屏状态，如果触摸屏被按下，则根据触摸位置切换窗口的显示。在三个窗口的回调函数中不需要处理触屏事件，因为触屏事件已经由主循环处理。