Android 6.0蓝牙程序无法发现任何可用的蓝牙设备

Question

GOAL

Discovering all the available bluetooth devices such as my iPad with bluetooth ON (Discoverable).

ANDROID VERSION

6.0

PROBLEM

Cannot Discover any bluetooth devices.

CODE

// Permission
<uses-permission android:name="android.permission.BLUETOOTH" />
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />

public BroadcastReceiver mReceiver;
public IntentFilter filter;

private boolean discover_AvailableBluetoothDevice() {
        mReceiver = new BroadcastReceiver() {
            public void onReceive(Context context, Intent intent) {
                Log.d(TAG, "onReceive Called");
                String action = intent.getAction();
                // When discovery finds a device
                if (BluetoothAdapter.ACTION_DISCOVERY_STARTED.equals(action)) {
                    Log.d(TAG, "ACTION_DISCOVERY_STARTED");
                } else if (BluetoothAdapter.ACTION_DISCOVERY_FINISHED.equals(action)) {
                    Log.d(TAG, "ACTION_DISCOVERY_FINISHED");
                } else if (BluetoothDevice.ACTION_FOUND.equals(action)) {
                    Log.d(TAG, "ACTION_FOUND");
                    // Get the BluetoothDevice object from the Intent
                    BluetoothDevice device = (BluetoothDevice) intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
                    // Add the name and address to an array adapter to show in a ListView
                    String str = device.getName() + "\n( " + device.getAddress() + " )";
                    adapter.add(str);
                }
            }
        };

        filter = new IntentFilter();
        filter.addAction(BluetoothDevice.ACTION_FOUND);
        filter.addAction(BluetoothAdapter.ACTION_DISCOVERY_STARTED);
        filter.addAction(BluetoothAdapter.ACTION_DISCOVERY_FINISHED);
        registerReceiver(mReceiver, filter);
        boolean isSuccessDiscovery = mBluetoothAdapter.startDiscovery();
        return isSuccessDiscovery;
    }

EXECUTION RESULT (logcat)

02-02 01:17:26.142 7194-7194/eie.imt.smartswitch D/†MainActivity: This device support Bluetooth.
02-02 01:17:55.052 7194-7194/eie.imt.smartswitch D/†ConnectSwitchActivity: isSuccessDiscovery=true
02-02 01:17:55.147 7194-7194/eie.imt.smartswitch D/†ConnectSwitchActivity: onReceive Called
02-02 01:17:55.147 7194-7194/eie.imt.smartswitch D/†ConnectSwitchActivity: ACTION_DISCOVERY_STARTED
02-02 01:18:07.909 7194-7194/eie.imt.smartswitch D/†ConnectSwitchActivity: onReceive Called
02-02 01:18:07.910 7194-7194/eie.imt.smartswitch D/†ConnectSwitchActivity: ACTION_DISCOVERY_FINISHED

I see the program does not enter the condition block of ACTION_FOUND but my iPad's bluetooth is ON, where does the problem come from?

Answer 1

If you use Android 6, add one of the following permissions:

<uses-permission android:name="android.permission.ACCESS_FINE_LOCTION" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />

And turn on the Location service (GPS):

And turn on the Location permission:

Google now requires ACCESS_FINE_LOCTION or ACCESS_COARCE_LOCATION permissions to be able to scan for Bluetooth or Wifi devices. It's weird behavior but Google says it's how it should work from now on.

Link to AndroidDev about this