Cut release 0.8.1

## Summary

* HTML files are now static, streamed directly to the client without
modification
* For any dynamic values, load via JSON APIs
* For files page, we stream the JSON content as we scan the directory to
avoid holding onto too much data

## Additional details

* We were previously building up a very large string all generated on
the X4 directly, we should be leveraging the browser
* Fixes https://github.com/daveallie/crosspoint-reader/issues/94

platformio.ini

@@ -1,5 +1,5 @@
 [platformio]
-crosspoint_version = 0.8.0
+crosspoint_version = 0.8.1
 default_envs = default
 
 [base]
@@ -9,7 +9,7 @@ framework = arduino
 monitor_speed = 115200
 upload_speed = 921600
 check_tool = cppcheck
-check_flags = --enable=all --suppress=missingIncludeSystem --suppress=unusedFunction --suppress=unmatchedSuppression --inline-suppr
+check_flags = --enable=all --suppress=missingIncludeSystem --suppress=unusedFunction --suppress=unmatchedSuppression --suppress=*:*/.pio/* --inline-suppr
 check_skip_packages = yes
 
 board_upload.flash_size = 16MB
@@ -39,6 +39,7 @@ lib_deps =
   BatteryMonitor=symlink://open-x4-sdk/libs/hardware/BatteryMonitor
   InputManager=symlink://open-x4-sdk/libs/hardware/InputManager
   EInkDisplay=symlink://open-x4-sdk/libs/display/EInkDisplay
+  ArduinoJson @ 7.4.2
 
 [env:default]
 extends = base

src/activities/Activity.h

@@ -1,19 +1,25 @@
 #pragma once
-#include <InputManager.h>
 
+#include <HardwareSerial.h>
+
+#include <string>
+#include <utility>
+
+class InputManager;
 class GfxRenderer;
 
 class Activity {
  protected:
+  std::string name;
   GfxRenderer& renderer;
   InputManager& inputManager;
 
  public:
-  explicit Activity(GfxRenderer& renderer, InputManager& inputManager)
-      : renderer(renderer), inputManager(inputManager) {}
+  explicit Activity(std::string name, GfxRenderer& renderer, InputManager& inputManager)
+      : name(std::move(name)), renderer(renderer), inputManager(inputManager) {}
   virtual ~Activity() = default;
-  virtual void onEnter() {}
-  virtual void onExit() {}
+  virtual void onEnter() { Serial.printf("[%lu] [ACT] Entering activity: %s\n", millis(), name.c_str()); }
+  virtual void onExit() { Serial.printf("[%lu] [ACT] Exiting activity: %s\n", millis(), name.c_str()); }
   virtual void loop() {}
   virtual bool skipLoopDelay() { return false; }
 };

src/activities/ActivityWithSubactivity.cpp

@@ -18,4 +18,7 @@ void ActivityWithSubactivity::loop() {
   }
 }
 
-void ActivityWithSubactivity::onExit() { exitActivity(); }
+void ActivityWithSubactivity::onExit() {
+  Activity::onExit();
+  exitActivity();
+}

src/activities/ActivityWithSubactivity.h

@@ -10,8 +10,8 @@ class ActivityWithSubactivity : public Activity {
   void enterNewActivity(Activity* activity);
 
  public:
-  explicit ActivityWithSubactivity(GfxRenderer& renderer, InputManager& inputManager)
-      : Activity(renderer, inputManager) {}
+  explicit ActivityWithSubactivity(std::string name, GfxRenderer& renderer, InputManager& inputManager)
+      : Activity(std::move(name), renderer, inputManager) {}
   void loop() override;
   void onExit() override;
 };

src/activities/boot_sleep/BootActivity.cpp

@@ -6,6 +6,8 @@
 #include "images/CrossLarge.h"
 
 void BootActivity::onEnter() {
+  Activity::onEnter();
+
   const auto pageWidth = GfxRenderer::getScreenWidth();
   const auto pageHeight = GfxRenderer::getScreenHeight();
 

src/activities/boot_sleep/BootActivity.h

@@ -3,6 +3,6 @@
 
 class BootActivity final : public Activity {
  public:
-  explicit BootActivity(GfxRenderer& renderer, InputManager& inputManager) : Activity(renderer, inputManager) {}
+  explicit BootActivity(GfxRenderer& renderer, InputManager& inputManager) : Activity("Boot", renderer, inputManager) {}
   void onEnter() override;
 };

src/activities/boot_sleep/SleepActivity.cpp

@@ -12,6 +12,7 @@
 #include "images/CrossLarge.h"
 
 void SleepActivity::onEnter() {
+  Activity::onEnter();
   renderPopup("Entering Sleep...");
 
   if (SETTINGS.sleepScreen == CrossPointSettings::SLEEP_SCREEN_MODE::CUSTOM) {
@@ -170,11 +171,16 @@ void SleepActivity::renderBitmapSleepScreen(const Bitmap& bitmap) const {
 }
 
 void SleepActivity::renderCoverSleepScreen() const {
+  if (APP_STATE.openEpubPath.empty()) {
+    return renderDefaultSleepScreen();
+  }
+
   Epub lastEpub(APP_STATE.openEpubPath, "/.crosspoint");
   if (!lastEpub.load()) {
     Serial.println("[SLP] Failed to load last epub");
     return renderDefaultSleepScreen();
   }
+
   if (!lastEpub.generateCoverBmp()) {
     Serial.println("[SLP] Failed to generate cover bmp");
     return renderDefaultSleepScreen();

src/activities/boot_sleep/SleepActivity.h

@@ -5,7 +5,8 @@ class Bitmap;
 
 class SleepActivity final : public Activity {
  public:
-  explicit SleepActivity(GfxRenderer& renderer, InputManager& inputManager) : Activity(renderer, inputManager) {}
+  explicit SleepActivity(GfxRenderer& renderer, InputManager& inputManager)
+      : Activity("Sleep", renderer, inputManager) {}
   void onEnter() override;
 
  private:

src/activities/home/HomeActivity.cpp

@@ -1,6 +1,7 @@
 #include "HomeActivity.h"
 
 #include <GfxRenderer.h>
+#include <InputManager.h>
 #include <SD.h>
 
 #include "config.h"
@@ -15,6 +16,8 @@ void HomeActivity::taskTrampoline(void* param) {
 }
 
 void HomeActivity::onEnter() {
+  Activity::onEnter();
+
   renderingMutex = xSemaphoreCreateMutex();
 
   selectorIndex = 0;
@@ -31,6 +34,8 @@ void HomeActivity::onEnter() {
 }
 
 void HomeActivity::onExit() {
+  Activity::onExit();
+
   // Wait until not rendering to delete task to avoid killing mid-instruction to EPD
   xSemaphoreTake(renderingMutex, portMAX_DELAY);
   if (displayTaskHandle) {
@@ -79,8 +84,8 @@ void HomeActivity::displayTaskLoop() {
 void HomeActivity::render() const {
   renderer.clearScreen();
 
-  const auto pageWidth = GfxRenderer::getScreenWidth();
-  const auto pageHeight = GfxRenderer::getScreenHeight();
+  const auto pageWidth = renderer.getScreenWidth();
+  const auto pageHeight = renderer.getScreenHeight();
   renderer.drawCenteredText(READER_FONT_ID, 10, "CrossPoint Reader", true, BOLD);
 
   // Draw selection

src/activities/home/HomeActivity.h

@@ -23,7 +23,7 @@ class HomeActivity final : public Activity {
  public:
   explicit HomeActivity(GfxRenderer& renderer, InputManager& inputManager, const std::function<void()>& onReaderOpen,
                         const std::function<void()>& onSettingsOpen, const std::function<void()>& onFileTransferOpen)
-      : Activity(renderer, inputManager),
+      : Activity("Home", renderer, inputManager),
         onReaderOpen(onReaderOpen),
         onSettingsOpen(onSettingsOpen),
         onFileTransferOpen(onFileTransferOpen) {}

src/activities/network/CrossPointWebServerActivity.cpp

@@ -1,8 +1,10 @@
 #include "CrossPointWebServerActivity.h"
 
 #include <GfxRenderer.h>
+#include <InputManager.h>
 #include <WiFi.h>
 
+#include "WifiSelectionActivity.h"
 #include "config.h"
 
 void CrossPointWebServerActivity::taskTrampoline(void* param) {
@@ -11,7 +13,8 @@ void CrossPointWebServerActivity::taskTrampoline(void* param) {
 }
 
 void CrossPointWebServerActivity::onEnter() {
-  Serial.printf("[%lu] [WEBACT] ========== CrossPointWebServerActivity onEnter ==========\n", millis());
+  ActivityWithSubactivity::onEnter();
+
   Serial.printf("[%lu] [WEBACT] [MEM] Free heap at onEnter: %d bytes\n", millis(), ESP.getFreeHeap());
 
   renderingMutex = xSemaphoreCreateMutex();
@@ -36,13 +39,13 @@ void CrossPointWebServerActivity::onEnter() {
 
   // Launch WiFi selection subactivity
   Serial.printf("[%lu] [WEBACT] Launching WifiSelectionActivity...\n", millis());
-  wifiSelection.reset(new WifiSelectionActivity(renderer, inputManager,
-                                                [this](bool connected) { onWifiSelectionComplete(connected); }));
-  wifiSelection->onEnter();
+  enterNewActivity(new WifiSelectionActivity(renderer, inputManager,
+                                             [this](const bool connected) { onWifiSelectionComplete(connected); }));
 }
 
 void CrossPointWebServerActivity::onExit() {
-  Serial.printf("[%lu] [WEBACT] ========== CrossPointWebServerActivity onExit START ==========\n", millis());
+  ActivityWithSubactivity::onExit();
+
   Serial.printf("[%lu] [WEBACT] [MEM] Free heap at onExit start: %d bytes\n", millis(), ESP.getFreeHeap());
 
   state = WebServerActivityState::SHUTTING_DOWN;
@@ -50,14 +53,6 @@ void CrossPointWebServerActivity::onExit() {
   // Stop the web server first (before disconnecting WiFi)
   stopWebServer();
 
-  // Exit WiFi selection subactivity if still active
-  if (wifiSelection) {
-    Serial.printf("[%lu] [WEBACT] Exiting WifiSelectionActivity...\n", millis());
-    wifiSelection->onExit();
-    wifiSelection.reset();
-    Serial.printf("[%lu] [WEBACT] WifiSelectionActivity exited\n", millis());
-  }
-
   // CRITICAL: Wait for LWIP stack to flush any pending packets
   Serial.printf("[%lu] [WEBACT] Waiting 500ms for network stack to flush pending packets...\n", millis());
   delay(500);
@@ -92,20 +87,17 @@ void CrossPointWebServerActivity::onExit() {
   Serial.printf("[%lu] [WEBACT] Mutex deleted\n", millis());
 
   Serial.printf("[%lu] [WEBACT] [MEM] Free heap at onExit end: %d bytes\n", millis(), ESP.getFreeHeap());
-  Serial.printf("[%lu] [WEBACT] ========== CrossPointWebServerActivity onExit COMPLETE ==========\n", millis());
 }
 
-void CrossPointWebServerActivity::onWifiSelectionComplete(bool connected) {
+void CrossPointWebServerActivity::onWifiSelectionComplete(const bool connected) {
   Serial.printf("[%lu] [WEBACT] WifiSelectionActivity completed, connected=%d\n", millis(), connected);
 
   if (connected) {
     // Get connection info before exiting subactivity
-    connectedIP = wifiSelection->getConnectedIP();
+    connectedIP = static_cast<WifiSelectionActivity*>(subActivity.get())->getConnectedIP();
     connectedSSID = WiFi.SSID().c_str();
 
-    // Exit the wifi selection subactivity
-    wifiSelection->onExit();
-    wifiSelection.reset();
+    exitActivity();
 
     // Start the web server
     startWebServer();
@@ -150,47 +142,40 @@ void CrossPointWebServerActivity::stopWebServer() {
 }
 
 void CrossPointWebServerActivity::loop() {
+  if (subActivity) {
+    // Forward loop to subactivity
+    subActivity->loop();
+    return;
+  }
+
   // Handle different states
-  switch (state) {
-    case WebServerActivityState::WIFI_SELECTION:
-      // Forward loop to WiFi selection subactivity
-      if (wifiSelection) {
-        wifiSelection->loop();
-      }
-      break;
+  if (state == WebServerActivityState::SERVER_RUNNING) {
+    // Handle web server requests - call handleClient multiple times per loop
+    // to improve responsiveness and upload throughput
+    if (webServer && webServer->isRunning()) {
+      const unsigned long timeSinceLastHandleClient = millis() - lastHandleClientTime;
 
-    case WebServerActivityState::SERVER_RUNNING:
-      // Handle web server requests - call handleClient multiple times per loop
-      // to improve responsiveness and upload throughput
-      if (webServer && webServer->isRunning()) {
-        unsigned long timeSinceLastHandleClient = millis() - lastHandleClientTime;
-
-        // Log if there's a significant gap between handleClient calls (>100ms)
-        if (lastHandleClientTime > 0 && timeSinceLastHandleClient > 100) {
-          Serial.printf("[%lu] [WEBACT] WARNING: %lu ms gap since last handleClient\n", millis(),
-                        timeSinceLastHandleClient);
-        }
-
-        // Call handleClient multiple times to process pending requests faster
-        // This is critical for upload performance - HTTP file uploads send data
-        // in chunks and each handleClient() call processes incoming data
-        constexpr int HANDLE_CLIENT_ITERATIONS = 10;
-        for (int i = 0; i < HANDLE_CLIENT_ITERATIONS && webServer->isRunning(); i++) {
-          webServer->handleClient();
-        }
-        lastHandleClientTime = millis();
+      // Log if there's a significant gap between handleClient calls (>100ms)
+      if (lastHandleClientTime > 0 && timeSinceLastHandleClient > 100) {
+        Serial.printf("[%lu] [WEBACT] WARNING: %lu ms gap since last handleClient\n", millis(),
+                      timeSinceLastHandleClient);
       }
 
-      // Handle exit on Back button
-      if (inputManager.wasPressed(InputManager::BTN_BACK)) {
-        onGoBack();
-        return;
+      // Call handleClient multiple times to process pending requests faster
+      // This is critical for upload performance - HTTP file uploads send data
+      // in chunks and each handleClient() call processes incoming data
+      constexpr int HANDLE_CLIENT_ITERATIONS = 10;
+      for (int i = 0; i < HANDLE_CLIENT_ITERATIONS && webServer->isRunning(); i++) {
+        webServer->handleClient();
       }
-      break;
+      lastHandleClientTime = millis();
+    }
 
-    case WebServerActivityState::SHUTTING_DOWN:
-      // Do nothing - waiting for cleanup
-      break;
+    // Handle exit on Back button
+    if (inputManager.wasPressed(InputManager::BTN_BACK)) {
+      onGoBack();
+      return;
+    }
   }
 }
 

src/activities/network/CrossPointWebServerActivity.h

@@ -7,9 +7,8 @@
 #include <memory>
 #include <string>
 
-#include "../Activity.h"
-#include "WifiSelectionActivity.h"
-#include "server/CrossPointWebServer.h"
+#include "activities/ActivityWithSubactivity.h"
+#include "network/CrossPointWebServer.h"
 
 // Web server activity states
 enum class WebServerActivityState {
@@ -26,16 +25,13 @@ enum class WebServerActivityState {
  * - Handles client requests in its loop() function
  * - Cleans up the server and shuts down WiFi on exit
  */
-class CrossPointWebServerActivity final : public Activity {
+class CrossPointWebServerActivity final : public ActivityWithSubactivity {
   TaskHandle_t displayTaskHandle = nullptr;
   SemaphoreHandle_t renderingMutex = nullptr;
   bool updateRequired = false;
   WebServerActivityState state = WebServerActivityState::WIFI_SELECTION;
   const std::function<void()> onGoBack;
 
-  // WiFi selection subactivity
-  std::unique_ptr<WifiSelectionActivity> wifiSelection;
-
   // Web server - owned by this activity
   std::unique_ptr<CrossPointWebServer> webServer;
 
@@ -58,7 +54,7 @@ class CrossPointWebServerActivity final : public Activity {
  public:
   explicit CrossPointWebServerActivity(GfxRenderer& renderer, InputManager& inputManager,
                                        const std::function<void()>& onGoBack)
-      : Activity(renderer, inputManager), onGoBack(onGoBack) {}
+      : ActivityWithSubactivity("CrossPointWebServer", renderer, inputManager), onGoBack(onGoBack) {}
   void onEnter() override;
   void onExit() override;
   void loop() override;

src/activities/network/WifiSelectionActivity.cpp

@@ -6,6 +6,7 @@
 #include <map>
 
 #include "WifiCredentialStore.h"
+#include "activities/util/KeyboardEntryActivity.h"
 #include "config.h"
 
 void WifiSelectionActivity::taskTrampoline(void* param) {
@@ -14,10 +15,14 @@ void WifiSelectionActivity::taskTrampoline(void* param) {
 }
 
 void WifiSelectionActivity::onEnter() {
+  Activity::onEnter();
+
   renderingMutex = xSemaphoreCreateMutex();
 
-  // Load saved WiFi credentials
+  // Load saved WiFi credentials - SD card operations need lock as we use SPI for both
+  xSemaphoreTake(renderingMutex, portMAX_DELAY);
   WIFI_STORE.loadFromFile();
+  xSemaphoreGive(renderingMutex);
 
   // Reset state
   selectedNetworkIndex = 0;
@@ -30,7 +35,6 @@ void WifiSelectionActivity::onEnter() {
   usedSavedPassword = false;
   savePromptSelection = 0;
   forgetPromptSelection = 0;
-  keyboard.reset();
 
   // Trigger first update to show scanning message
   updateRequired = true;
@@ -47,7 +51,8 @@ void WifiSelectionActivity::onEnter() {
 }
 
 void WifiSelectionActivity::onExit() {
-  Serial.printf("[%lu] [WIFI] ========== WifiSelectionActivity onExit START ==========\n", millis());
+  Activity::onExit();
+
   Serial.printf("[%lu] [WIFI] [MEM] Free heap at onExit start: %d bytes\n", millis(), ESP.getFreeHeap());
 
   // Stop any ongoing WiFi scan
@@ -78,7 +83,6 @@ void WifiSelectionActivity::onExit() {
   Serial.printf("[%lu] [WIFI] Mutex deleted\n", millis());
 
   Serial.printf("[%lu] [WIFI] [MEM] Free heap at onExit end: %d bytes\n", millis(), ESP.getFreeHeap());
-  Serial.printf("[%lu] [WIFI] ========== WifiSelectionActivity onExit COMPLETE ==========\n", millis());
 }
 
 void WifiSelectionActivity::startWifiScan() {
@@ -96,7 +100,7 @@ void WifiSelectionActivity::startWifiScan() {
 }
 
 void WifiSelectionActivity::processWifiScanResults() {
-  int16_t scanResult = WiFi.scanComplete();
+  const int16_t scanResult = WiFi.scanComplete();
 
   if (scanResult == WIFI_SCAN_RUNNING) {
     // Scan still in progress
@@ -115,7 +119,7 @@ void WifiSelectionActivity::processWifiScanResults() {
 
   for (int i = 0; i < scanResult; i++) {
     std::string ssid = WiFi.SSID(i).c_str();
-    int32_t rssi = WiFi.RSSI(i);
+    const int32_t rssi = WiFi.RSSI(i);
 
     // Skip hidden networks (empty SSID)
     if (ssid.empty()) {
@@ -152,7 +156,7 @@ void WifiSelectionActivity::processWifiScanResults() {
   updateRequired = true;
 }
 
-void WifiSelectionActivity::selectNetwork(int index) {
+void WifiSelectionActivity::selectNetwork(const int index) {
   if (index < 0 || index >= static_cast<int>(networks.size())) {
     return;
   }
@@ -178,11 +182,11 @@ void WifiSelectionActivity::selectNetwork(int index) {
   if (selectedRequiresPassword) {
     // Show password entry
     state = WifiSelectionState::PASSWORD_ENTRY;
-    keyboard.reset(new KeyboardEntryActivity(renderer, inputManager, "Enter WiFi Password",
-                                             "",    // No initial text
-                                             64,    // Max password length
-                                             false  // Show password by default (hard keyboard to use)
-                                             ));
+    enterNewActivity(new KeyboardEntryActivity(renderer, inputManager, "Enter WiFi Password",
+                                               "",    // No initial text
+                                               64,    // Max password length
+                                               false  // Show password by default (hard keyboard to use)
+                                               ));
     updateRequired = true;
   } else {
     // Connect directly for open networks
@@ -200,8 +204,8 @@ void WifiSelectionActivity::attemptConnection() {
   WiFi.mode(WIFI_STA);
 
   // Get password from keyboard if we just entered it
-  if (keyboard && !usedSavedPassword) {
-    enteredPassword = keyboard->getText();
+  if (subActivity && !usedSavedPassword) {
+    enteredPassword = static_cast<KeyboardEntryActivity*>(subActivity.get())->getText();
   }
 
   if (selectedRequiresPassword && !enteredPassword.empty()) {
@@ -216,7 +220,7 @@ void WifiSelectionActivity::checkConnectionStatus() {
     return;
   }
 
-  wl_status_t status = WiFi.status();
+  const wl_status_t status = WiFi.status();
 
   if (status == WL_CONNECTED) {
     // Successfully connected
@@ -273,7 +277,8 @@ void WifiSelectionActivity::loop() {
   }
 
   // Handle password entry state
-  if (state == WifiSelectionState::PASSWORD_ENTRY && keyboard) {
+  if (state == WifiSelectionState::PASSWORD_ENTRY && subActivity) {
+    const auto keyboard = static_cast<KeyboardEntryActivity*>(subActivity.get());
     keyboard->handleInput();
 
     if (keyboard->isComplete()) {
@@ -283,7 +288,7 @@ void WifiSelectionActivity::loop() {
 
     if (keyboard->isCancelled()) {
       state = WifiSelectionState::NETWORK_LIST;
-      keyboard.reset();
+      exitActivity();
       updateRequired = true;
       return;
     }
@@ -307,7 +312,9 @@ void WifiSelectionActivity::loop() {
     } else if (inputManager.wasPressed(InputManager::BTN_CONFIRM)) {
       if (savePromptSelection == 0) {
         // User chose "Yes" - save the password
+        xSemaphoreTake(renderingMutex, portMAX_DELAY);
         WIFI_STORE.addCredential(selectedSSID, enteredPassword);
+        xSemaphoreGive(renderingMutex);
       }
       // Complete - parent will start web server
       onComplete(true);
@@ -333,7 +340,9 @@ void WifiSelectionActivity::loop() {
     } else if (inputManager.wasPressed(InputManager::BTN_CONFIRM)) {
       if (forgetPromptSelection == 0) {
         // User chose "Yes" - forget the network
+        xSemaphoreTake(renderingMutex, portMAX_DELAY);
         WIFI_STORE.removeCredential(selectedSSID);
+        xSemaphoreGive(renderingMutex);
         // Update the network list to reflect the change
         const auto network = find_if(networks.begin(), networks.end(),
                                      [this](const WifiNetworkInfo& net) { return net.ssid == selectedSSID; });
@@ -408,15 +417,18 @@ void WifiSelectionActivity::loop() {
   }
 }
 
-std::string WifiSelectionActivity::getSignalStrengthIndicator(int32_t rssi) const {
+std::string WifiSelectionActivity::getSignalStrengthIndicator(const int32_t rssi) const {
   // Convert RSSI to signal bars representation
   if (rssi >= -50) {
     return "||||";  // Excellent
-  } else if (rssi >= -60) {
+  }
+  if (rssi >= -60) {
     return "||| ";  // Good
-  } else if (rssi >= -70) {
+  }
+  if (rssi >= -70) {
     return "||  ";  // Fair
-  } else if (rssi >= -80) {
+  }
+  if (rssi >= -80) {
     return "|   ";  // Weak
   }
   return "    ";  // Very weak
@@ -482,8 +494,8 @@ void WifiSelectionActivity::renderNetworkList() const {
     renderer.drawCenteredText(SMALL_FONT_ID, top + height + 10, "Press OK to scan again", true, REGULAR);
   } else {
     // Calculate how many networks we can display
-    const int startY = 60;
-    const int lineHeight = 25;
+    constexpr int startY = 60;
+    constexpr int lineHeight = 25;
     const int maxVisibleNetworks = (pageHeight - startY - 40) / lineHeight;
 
     // Calculate scroll offset to keep selected item visible
@@ -555,8 +567,8 @@ void WifiSelectionActivity::renderPasswordEntry() const {
   renderer.drawCenteredText(UI_FONT_ID, 38, networkInfo.c_str(), true, REGULAR);
 
   // Draw keyboard
-  if (keyboard) {
-    keyboard->render(58);
+  if (subActivity) {
+    static_cast<KeyboardEntryActivity*>(subActivity.get())->render(58);
   }
 }
 
@@ -591,7 +603,7 @@ void WifiSelectionActivity::renderConnected() const {
   }
   renderer.drawCenteredText(UI_FONT_ID, top + 10, ssidInfo.c_str(), true, REGULAR);
 
-  std::string ipInfo = "IP Address: " + connectedIP;
+  const std::string ipInfo = "IP Address: " + connectedIP;
   renderer.drawCenteredText(UI_FONT_ID, top + 40, ipInfo.c_str(), true, REGULAR);
 
   renderer.drawCenteredText(SMALL_FONT_ID, pageHeight - 30, "Press any button to continue", true, REGULAR);
@@ -615,9 +627,9 @@ void WifiSelectionActivity::renderSavePrompt() const {
 
   // Draw Yes/No buttons
   const int buttonY = top + 80;
-  const int buttonWidth = 60;
-  const int buttonSpacing = 30;
-  const int totalWidth = buttonWidth * 2 + buttonSpacing;
+  constexpr int buttonWidth = 60;
+  constexpr int buttonSpacing = 30;
+  constexpr int totalWidth = buttonWidth * 2 + buttonSpacing;
   const int startX = (pageWidth - totalWidth) / 2;
 
   // Draw "Yes" button
@@ -665,9 +677,9 @@ void WifiSelectionActivity::renderForgetPrompt() const {
 
   // Draw Yes/No buttons
   const int buttonY = top + 80;
-  const int buttonWidth = 60;
-  const int buttonSpacing = 30;
-  const int totalWidth = buttonWidth * 2 + buttonSpacing;
+  constexpr int buttonWidth = 60;
+  constexpr int buttonSpacing = 30;
+  constexpr int totalWidth = buttonWidth * 2 + buttonSpacing;
   const int startX = (pageWidth - totalWidth) / 2;
 
   // Draw "Yes" button

src/activities/network/WifiSelectionActivity.h

@@ -9,8 +9,7 @@
 #include <string>
 #include <vector>
 
-#include "../Activity.h"
-#include "../util/KeyboardEntryActivity.h"
+#include "activities/ActivityWithSubactivity.h"
 
 // Structure to hold WiFi network information
 struct WifiNetworkInfo {
@@ -43,7 +42,7 @@ enum class WifiSelectionState {
  *
  * The onComplete callback receives true if connected successfully, false if cancelled.
  */
-class WifiSelectionActivity final : public Activity {
+class WifiSelectionActivity final : public ActivityWithSubactivity {
   TaskHandle_t displayTaskHandle = nullptr;
   SemaphoreHandle_t renderingMutex = nullptr;
   bool updateRequired = false;
@@ -56,9 +55,6 @@ class WifiSelectionActivity final : public Activity {
   std::string selectedSSID;
   bool selectedRequiresPassword = false;
 
-  // On-screen keyboard for password entry
-  std::unique_ptr<KeyboardEntryActivity> keyboard;
-
   // Connection result
   std::string connectedIP;
   std::string connectionError;
@@ -98,7 +94,7 @@ class WifiSelectionActivity final : public Activity {
  public:
   explicit WifiSelectionActivity(GfxRenderer& renderer, InputManager& inputManager,
                                  const std::function<void(bool connected)>& onComplete)
-      : Activity(renderer, inputManager), onComplete(onComplete) {}
+      : ActivityWithSubactivity("WifiSelection", renderer, inputManager), onComplete(onComplete) {}
   void onEnter() override;
   void onExit() override;
   void loop() override;

src/activities/reader/EpubReaderActivity.cpp

@@ -2,6 +2,7 @@
 
 #include <Epub/Page.h>
 #include <GfxRenderer.h>
+#include <InputManager.h>
 #include <SD.h>
 
 #include "Battery.h"
@@ -26,6 +27,8 @@ void EpubReaderActivity::taskTrampoline(void* param) {
 }
 
 void EpubReaderActivity::onEnter() {
+  ActivityWithSubactivity::onEnter();
+
   if (!epub) {
     return;
   }
@@ -61,6 +64,8 @@ void EpubReaderActivity::onEnter() {
 }
 
 void EpubReaderActivity::onExit() {
+  ActivityWithSubactivity::onExit();
+
   // Wait until not rendering to delete task to avoid killing mid-instruction to EPD
   xSemaphoreTake(renderingMutex, portMAX_DELAY);
   if (displayTaskHandle) {
@@ -75,8 +80,8 @@ void EpubReaderActivity::onExit() {
 
 void EpubReaderActivity::loop() {
   // Pass input responsibility to sub activity if exists
-  if (subAcitivity) {
-    subAcitivity->loop();
+  if (subActivity) {
+    subActivity->loop();
     return;
   }
 
@@ -84,11 +89,11 @@ void EpubReaderActivity::loop() {
   if (inputManager.wasPressed(InputManager::BTN_CONFIRM)) {
     // Don't start activity transition while rendering
     xSemaphoreTake(renderingMutex, portMAX_DELAY);
-    subAcitivity.reset(new EpubReaderChapterSelectionActivity(
+    exitActivity();
+    enterNewActivity(new EpubReaderChapterSelectionActivity(
         this->renderer, this->inputManager, epub, currentSpineIndex,
         [this] {
-          subAcitivity->onExit();
-          subAcitivity.reset();
+          exitActivity();
           updateRequired = true;
         },
         [this](const int newSpineIndex) {
@@ -97,11 +102,9 @@ void EpubReaderActivity::loop() {
             nextPageNumber = 0;
             section.reset();
           }
-          subAcitivity->onExit();
-          subAcitivity.reset();
+          exitActivity();
           updateRequired = true;
         }));
-    subAcitivity->onEnter();
     xSemaphoreGive(renderingMutex);
   }
 
@@ -330,8 +333,8 @@ void EpubReaderActivity::renderStatusBar() const {
   constexpr auto textY = 776;
 
   // Calculate progress in book
-  float sectionChapterProg = static_cast<float>(section->currentPage) / section->pageCount;
-  uint8_t bookProgress = epub->calculateProgress(currentSpineIndex, sectionChapterProg);
+  const float sectionChapterProg = static_cast<float>(section->currentPage) / section->pageCount;
+  const uint8_t bookProgress = epub->calculateProgress(currentSpineIndex, sectionChapterProg);
 
   // Right aligned text for progress counter
   const std::string progress = std::to_string(section->currentPage + 1) + "/" + std::to_string(section->pageCount) +

src/activities/reader/EpubReaderActivity.h

@@ -5,14 +5,13 @@
 #include <freertos/semphr.h>
 #include <freertos/task.h>
 
-#include "../Activity.h"
+#include "activities/ActivityWithSubactivity.h"
 
-class EpubReaderActivity final : public Activity {
+class EpubReaderActivity final : public ActivityWithSubactivity {
   std::shared_ptr<Epub> epub;
   std::unique_ptr<Section> section = nullptr;
   TaskHandle_t displayTaskHandle = nullptr;
   SemaphoreHandle_t renderingMutex = nullptr;
-  std::unique_ptr<Activity> subAcitivity = nullptr;
   int currentSpineIndex = 0;
   int nextPageNumber = 0;
   int pagesUntilFullRefresh = 0;
@@ -28,7 +27,7 @@ class EpubReaderActivity final : public Activity {
  public:
   explicit EpubReaderActivity(GfxRenderer& renderer, InputManager& inputManager, std::unique_ptr<Epub> epub,
                               const std::function<void()>& onGoBack)
-      : Activity(renderer, inputManager), epub(std::move(epub)), onGoBack(onGoBack) {}
+      : ActivityWithSubactivity("EpubReader", renderer, inputManager), epub(std::move(epub)), onGoBack(onGoBack) {}
   void onEnter() override;
   void onExit() override;
   void loop() override;

src/activities/reader/EpubReaderChapterSelectionActivity.cpp

@@ -1,6 +1,7 @@
 #include "EpubReaderChapterSelectionActivity.h"
 
 #include <GfxRenderer.h>
+#include <InputManager.h>
 #include <SD.h>
 
 #include "config.h"
@@ -16,6 +17,8 @@ void EpubReaderChapterSelectionActivity::taskTrampoline(void* param) {
 }
 
 void EpubReaderChapterSelectionActivity::onEnter() {
+  Activity::onEnter();
+
   if (!epub) {
     return;
   }
@@ -34,6 +37,8 @@ void EpubReaderChapterSelectionActivity::onEnter() {
 }
 
 void EpubReaderChapterSelectionActivity::onExit() {
+  Activity::onExit();
+
   // Wait until not rendering to delete task to avoid killing mid-instruction to EPD
   xSemaphoreTake(renderingMutex, portMAX_DELAY);
   if (displayTaskHandle) {

src/activities/reader/EpubReaderChapterSelectionActivity.h

@@ -27,7 +27,7 @@ class EpubReaderChapterSelectionActivity final : public Activity {
                                               const std::shared_ptr<Epub>& epub, const int currentSpineIndex,
                                               const std::function<void()>& onGoBack,
                                               const std::function<void(int newSpineIndex)>& onSelectSpineIndex)
-      : Activity(renderer, inputManager),
+      : Activity("EpubReaderChapterSelection", renderer, inputManager),
         epub(epub),
         currentSpineIndex(currentSpineIndex),
         onGoBack(onGoBack),

src/activities/reader/FileSelectionActivity.cpp

@@ -1,6 +1,7 @@
 #include "FileSelectionActivity.h"
 
 #include <GfxRenderer.h>
+#include <InputManager.h>
 #include <SD.h>
 
 #include "config.h"
@@ -48,6 +49,8 @@ void FileSelectionActivity::loadFiles() {
 }
 
 void FileSelectionActivity::onEnter() {
+  Activity::onEnter();
+
   renderingMutex = xSemaphoreCreateMutex();
 
   basepath = "/";
@@ -66,6 +69,8 @@ void FileSelectionActivity::onEnter() {
 }
 
 void FileSelectionActivity::onExit() {
+  Activity::onExit();
+
   // Wait until not rendering to delete task to avoid killing mid-instruction to EPD
   xSemaphoreTake(renderingMutex, portMAX_DELAY);
   if (displayTaskHandle) {

src/activities/reader/FileSelectionActivity.h

@@ -28,7 +28,7 @@ class FileSelectionActivity final : public Activity {
   explicit FileSelectionActivity(GfxRenderer& renderer, InputManager& inputManager,
                                  const std::function<void(const std::string&)>& onSelect,
                                  const std::function<void()>& onGoHome)
-      : Activity(renderer, inputManager), onSelect(onSelect), onGoHome(onGoHome) {}
+      : Activity("FileSelection", renderer, inputManager), onSelect(onSelect), onGoHome(onGoHome) {}
   void onEnter() override;
   void onExit() override;
   void loop() override;