關於Andorid O版本獲取不到藍牙地址的說明

以前提到過獲取系統的藍牙地址，最近發如今Anroid O版本上出現了沒法獲取的現象。通過不斷查詢，發現瞭解決方法是替換成下面的方案：

private String getBluetoothMacAddress() {
    BluetoothAdapter bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
    String bluetoothMacAddress = "";
    if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.M){
        try {
            Field mServiceField = bluetoothAdapter.getClass().getDeclaredField("mService");
            mServiceField.setAccessible(true);

            Object btManagerService = mServiceField.get(bluetoothAdapter);

            if (btManagerService != null) {
                bluetoothMacAddress = (String) btManagerService.getClass().getMethod("getAddress").invoke(btManagerService);
            }
        } catch (NoSuchFieldException e) {

        } catch (NoSuchMethodException e) {

        } catch (IllegalAccessException e) {

        } catch (InvocationTargetException e) {

        }
    } else {
        bluetoothMacAddress = bluetoothAdapter.getAddress();
    }
    return bluetoothMacAddress;
}

緣由在於在8.0版本上關於系統的權限作了更爲嚴格的要求，原有的經過Secure的映射獲取的方式已經被捨棄。目前經過BluetoothManagerService的反射獲取能夠獲得BT mac地址。

參考

• Get Bluetooth local mac address in Marshmallow -- StackOverflow
• Get proper Bluetooth Mac Address on Android O -- Github