WIP: New app: "Scan Bluetooth" (#58)

Just display a table and list all nearby Bluetooth devices

internal_filesystem/apps/com.micropythonos.scan_bluetooth/META-INF/MANIFEST.JSON

@@ -0,0 +1,24 @@
+{
+"name": "ScanBluetooth",
+"publisher": "MicroPythonOS",
+"short_description": "Scan Bluetooth",
+"long_description": "Lists all nearby Bluetooth devices with some information",
+"icon_url": "https://apps.micropythonos.com/apps/com.micropythonos.scan_bluetooth/icons/com.micropythonos.scan_bluetooth_0.0.1_64x64.png",
+"download_url": "https://apps.micropythonos.com/apps/com.micropythonos.scan_bluetooth/mpks/com.micropythonos.scan_bluetooth_0.0.1.mpk",
+"fullname": "com.micropythonos.scan_bluetooth",
+"version": "0.0.1",
+"category": "development",
+"activities": [
+    {
+      "entrypoint": "assets/scan_bluetooth.py",
+      "classname": "ScanBluetooth",
+      "intent_filters": [
+        {
+          "action": "main",
+          "category": "launcher"
+        }
+      ]
+    }
+  ]
+}
+

internal_filesystem/apps/com.micropythonos.scan_bluetooth/assets/scan_bluetooth.py

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+"""
+Initial author: https://github.com/jedie
+https://docs.micropython.org/en/latest/library/bluetooth.html
+"""
+
+import time
+
+import bluetooth
+import lvgl as lv
+from micropython import const
+from mpos import Activity
+
+SCAN_DURATION = const(1000)  # Duration of each BLE scan in milliseconds
+_IRQ_SCAN_RESULT = const(5)
+
+
+# BLE Advertising Data Types (Standardized by Bluetooth SIG)
+_ADV_TYPE_NAME = const(0x09)
+
+
+def decode_field(payload: bytes, adv_type: int) -> list:
+    results = []
+    i = 0
+    payload_len = len(payload)
+    while i < payload_len:
+        length = payload[i]
+        if length == 0 or i + length >= payload_len:
+            break
+        field_type = payload[i + 1]
+        if field_type == adv_type:
+            results.append(payload[i + 2 : i + length + 1])
+        i += length + 1
+    return results
+
+
+class BluetoothScanner:
+    def __init__(self, device_callback):
+        self.device_callback = device_callback
+        self.ble = bluetooth.BLE()
+        self.ble.irq(self.ble_irq_handler)
+
+    def __enter__(self):
+        print("Activating BLE")
+        self.ble.active(True)
+        return self
+
+    def ble_irq_handler(self, event: int, data: tuple) -> None:
+        if event == _IRQ_SCAN_RESULT:
+            addr_type, addr, adv_type, rssi, adv_data = data
+            addr = ":".join(f"{b:02x}" for b in addr)
+            names = decode_field(adv_data, _ADV_TYPE_NAME)
+            name = str(names[0], "utf-8") if names else "Unknown"
+            self.device_callback(addr, rssi, name)
+
+    def scan(self, duration_ms: int):
+        print(f"BLE scanning for {duration_ms}ms...")
+        self.ble.gap_scan(duration_ms, 20000, 10000)
+
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        print("Deactivating BLE")
+        self.ble.active(False)
+
+
+def set_dynamic_column_widths(table, font=None, padding=8):
+    font = font or lv.font_montserrat_14
+    for col in range(table.get_column_count()):
+        max_width = 0
+        for row in range(table.get_row_count()):
+            value = table.get_cell_value(row, col)
+            width = lv.text_get_width(value, len(value), font, lv.TEXT_FLAG.NONE)
+            if width > max_width:
+                max_width = width
+        table.set_column_width(col, max_width + padding)
+
+
+def set_cell_value(table, *, row: int, values: tuple):
+    for col, value in enumerate(values):
+        table.set_cell_value(row, col, value)
+
+
+class ScanBluetooth(Activity):
+    refresh_timer = None
+
+    def onCreate(self):
+        screen = lv.obj()
+        screen.set_flex_flow(lv.FLEX_FLOW.COLUMN)
+        screen.set_style_pad_all(0, 0)
+        screen.set_size(lv.pct(100), lv.pct(100))
+
+        self.table = lv.table(screen)
+        set_cell_value(
+            self.table,
+            row=0,
+            values=("pos", "MAC", "RSSI", "count", "Name"),
+        )
+        set_dynamic_column_widths(self.table)
+
+        self.mac2column = {}
+        self.mac2counts = {}
+
+        self.scanner_cm = BluetoothScanner(device_callback=self.scan_callback)
+        self.scanner = self.scanner_cm.__enter__()  # Activate BLE
+
+        self.setContentView(screen)
+
+    def scan_callback(self, addr, rssi, name):
+        if not (column_index := self.mac2column.get(addr)):
+            column_index = len(self.mac2column) + 1
+            self.mac2column[addr] = column_index
+            self.mac2counts[addr] = 1
+        else:
+            self.mac2counts[addr] += 1
+
+        set_cell_value(
+            self.table,
+            row=column_index,
+            values=(
+                str(column_index),
+                addr,
+                f"{rssi} dBm",
+                str(self.mac2counts[addr]),
+                name,
+            ),
+        )
+
+    def onResume(self, screen):
+        super().onResume(screen)
+
+        def update(timer):
+            self.scanner.scan(SCAN_DURATION)
+            set_dynamic_column_widths(self.table)
+            time.sleep_ms(SCAN_DURATION + 100)  # Wait ?
+            print(f"Scan complete: {len(self.mac2column)} unique devices")
+
+        self.refresh_timer = lv.timer_create(update, SCAN_DURATION + 1000, None)
+
+    def onPause(self, screen):
+        super().onPause(screen)
+        self.scanner.__exit__(None, None, None)  # Deactivate BLE
+        if self.refresh_timer:
+            self.refresh_timer.delete()
+            self.refresh_timer = None