Bluetooth avec plusieurs fragments Android Studio

**k.bertrand** · 19/03/2018, 13h02

Bonjour à tous,

N'ayant pas de grandes connaissances en programmation Android, je viens vous sollicité pour un de mes problèmes. Je dois créer une application Android capable de transférer des données entre elle-même et une Raspberry. Comme j'ai besoin de faire plusieurs actions, j'ai décidé d'utiliser un navigation drawer avec les fragments. Pour la connexion à la Raspberry et l'ouverture de la connexion, le programme présent dans le fragment fonction très bien car la Raspberry m'informe que la communication est ouverte. Voici le programme:

Code :

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package com.gxabt.uliege.microspectro_v1.Controllers.Fragments;
 
import android.Manifest;
import android.app.Fragment;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Build;
import android.os.Bundle;
import android.support.v4.content.LocalBroadcastManager;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.Button;
import android.widget.ListView;
 
import com.gxabt.uliege.microspectro_v1.Models.BluetoothConnectionService;
import com.gxabt.uliege.microspectro_v1.Models.DeviceListAdapter;
import com.gxabt.uliege.microspectro_v1.R;
 
import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.Set;
import java.util.UUID;
 
public class ConnectionFragment extends Fragment implements AdapterView.OnItemClickListener {
    private static final String TAG = "ConnectionFragment";
    private static final UUID MY_UUID_INSECURE = UUID.fromString("00001105-0000-1000-8000-00805F9B34FB");
 
    public ArrayList<BluetoothDevice> mBTDevices;
    public Set<BluetoothDevice> mDeviceBonded;
    public DeviceListAdapter mDeviceListAdapter;
 
    BluetoothConnectionService mBluetoothConnection;
    BluetoothAdapter mBluetoothAdapter;
    BluetoothDevice mBTDevice;
    ListView lvDevices;
    Button btnStartConnection;
    Button btnSearch;
    StringBuilder message;
 
    public static ConnectionFragment newInstance() {
        return (new ConnectionFragment());
    }
 
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.fragment_connection, container, false);
 
        mBTDevices = new ArrayList<>();
 
        mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
 
        mDeviceBonded = mBluetoothAdapter.getBondedDevices();
 
        lvDevices = (ListView) rootView.findViewById(R.id.list_devices);
 
        for (BluetoothDevice bt : mDeviceBonded)
        {
            mBTDevices.add(bt);
        }
 
        mDeviceListAdapter = new DeviceListAdapter(getActivity(), R.layout.device_adapteur_view, mBTDevices);
        lvDevices.setAdapter(mDeviceListAdapter);
 
        IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_BOND_STATE_CHANGED);
        getActivity().registerReceiver(mBroadcastReceiverBound, filter);
        lvDevices.setOnItemClickListener(ConnectionFragment.this);
 
        btnStartConnection = (Button) rootView.findViewById(R.id.fragment_connect_btn_start);
        btnStartConnection.setOnClickListener(new View.OnClickListener()
        {
            @Override
            public void onClick(View view) {
                startConnection();
            }
        });
 
        btnSearch = (Button) rootView.findViewById(R.id.fragment_connect_btn_search);
        btnSearch.setOnClickListener(new View.OnClickListener()
        {
            @Override
            public void onClick(View view)
            {
                Log.d(TAG, "btnDiscover: Looking for unpaired devices...");
 
                if (mBluetoothAdapter.isDiscovering()) {
                    mBluetoothAdapter.cancelDiscovery();
                    Log.d(TAG, "btnDiscover: Canceling discovery.");
 
                    //Check BT permissions in manifest
                    checkBTPermissions();
 
                    mBluetoothAdapter.startDiscovery();
                    IntentFilter discoverDevicesIntent = new IntentFilter(BluetoothDevice.ACTION_FOUND);
                    getActivity().registerReceiver(mBroadcastReceiverDiscover, discoverDevicesIntent);
                }
                if (!mBluetoothAdapter.isDiscovering()) {
                    //Check BT permissions in manifest
                    checkBTPermissions();
 
                    mBluetoothAdapter.startDiscovery();
                    IntentFilter discoverDevicesIntent = new IntentFilter(BluetoothDevice.ACTION_FOUND);
                    getActivity().registerReceiver(mBroadcastReceiverDiscover, discoverDevicesIntent);
                }
            }
        });
 
        message = new StringBuilder();
        LocalBroadcastManager.getInstance(getActivity()).registerReceiver(mReceiver, new IntentFilter("incomingMessage"));
 
        return rootView;
    }
 
 
    public void startBTConnection(BluetoothDevice device, UUID uuid) {
        Log.d(TAG, "startBTConnection: Initializing RFCOM Bluetooth Connection");
 
        mBluetoothConnection.startClient(device, uuid);
    }
 
    //Remember the connection will fail and app will crash if you haven't paired first
    public void startConnection()
    {
        startBTConnection(mBTDevice, MY_UUID_INSECURE);
    }
 
    /*
        Discover new devices.
        This broadcast receiver is use for listening devices that are not yet paired.
     */
    private final BroadcastReceiver mBroadcastReceiverDiscover = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            final String action = intent.getAction();
            Log.d(TAG, "onReciver: ACTION FOUND.");
 
            if (action.equals(BluetoothDevice.ACTION_FOUND)) {
                BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
                Log.d(TAG, "onReceive: " + device.getName() + " : " + device.getAddress());
 
                int i = 0;
                for (; i < mBTDevices.size(); i++) {
                    if (device.getAddress().equals(mBTDevices.get(i).getAddress())) {
                        break;
                    }
                }
 
                if (i == mBTDevices.size()) {
                    mBTDevices.add(device);
                }
 
                mDeviceListAdapter = new DeviceListAdapter(context, R.layout.device_adapteur_view, mBTDevices);
                lvDevices.setAdapter(mDeviceListAdapter);
            }
        }
    };
 
    /*
        Bounding devices.
     */
    private final BroadcastReceiver mBroadcastReceiverBound = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            final String action = intent.getAction();
 
            if (action.equals(BluetoothDevice.ACTION_BOND_STATE_CHANGED)) {
                BluetoothDevice mDevice = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
                // Case 1: bounded already
                if (mDevice.getBondState() == BluetoothDevice.BOND_BONDED) {
                    Log.d(TAG, "BroadcastReceiver: BOND_BONDED.");
 
                    mBTDevice = mDevice;
                }
                // Case 2: creating a bone
                if (mDevice.getBondState() == BluetoothDevice.BOND_BONDING) {
                    Log.d(TAG, "BroadcastReceiver: BOND_BONDING.");
                }
                // Case 3: breaking a bond
                if (mDevice.getBondState() == BluetoothDevice.BOND_NONE) {
                    Log.d(TAG, "BroadcastReceiver: BOND_NONE.");
                }
            }
        }
    };
 
    BroadcastReceiver mReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            String text = intent.getStringExtra("theMessage");
 
            message.append(text + "\n");
        }
    };
 
    /*
        Check permissions method.
        This method is required for all devices running API23+.
        Android must programmatically check the permissions for Bluetooth.
        Putting the proper permissions in the manifest is not enough.
 
        NOTE: This will only execute on version >LOLLIPOP because it is not needed otherwise.
     */
    public void checkBTPermissions() {
        if (Build.VERSION.SDK_INT > Build.VERSION_CODES.LOLLIPOP) {
            int permissionCheck = this.getActivity().checkSelfPermission("Manifest.permission.ACCESS_FINE_LOCATION");
            permissionCheck += this.getActivity().checkSelfPermission("Manifest.permission.ACCESS_COARSE_LOCATION");
            if (permissionCheck != 0) {
                this.requestPermissions(new String[]{Manifest.permission.ACCESS_FINE_LOCATION, Manifest.permission.ACCESS_COARSE_LOCATION}, 1001); //Any number
            }
        } else {
            Log.d(TAG, "checkBTPermissions: No need to check permissions. SDK version < LOLLIPOP.");
        }
    }
 
    /*
        Bounding device - item click
     */
    @Override
    public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
        //First cancel discovery because its very memory intensive.
        mBluetoothAdapter.cancelDiscovery();
        Log.d(TAG, "onItemClick: You Clicked on a device.");
        String deviceName = mBTDevices.get(i).getName();
        String deviceAddress = mBTDevices.get(i).getAddress();
 
        Log.d(TAG, "onItemClick: " + deviceName);
        Log.d(TAG, "onItemClick: " + deviceAddress);
 
        //Create the bond
        //NOTE: Requires API 17+
        if (Build.VERSION.SDK_INT > Build.VERSION_CODES.ICE_CREAM_SANDWICH_MR1) {
            Log.d(TAG, "Trying to pair with " + deviceName);
            mBTDevices.get(i).createBond();
 
            mBTDevice = mBTDevices.get(i);
            mBluetoothConnection = new BluetoothConnectionService(getActivity());
        }
    }
}

Mais lorsque je change de fragment et que j'appuie sur le bouton pour envoyer les informations, j'obtiens un message d'erreur. Voici le programme du fragment d'envoi:

Code :

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package com.gxabt.uliege.microspectro_v1.Controllers.Fragments;
 
import android.app.Fragment;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
 
import com.gxabt.uliege.microspectro_v1.Controllers.Activities.MainActivity;
import com.gxabt.uliege.microspectro_v1.Models.BluetoothConnectionService;
import com.gxabt.uliege.microspectro_v1.R;
 
import java.nio.charset.Charset;
import java.util.UUID;
 
public class ReproductionFragment extends Fragment
{
    private static final UUID MY_UUID_INSECURE = UUID.fromString("00001105-0000-1000-8000-00805F9B34FB");
 
    Button btnReprod;
    BluetoothConnectionService mBluetoothConnection;
    ConnectionFragment dev;
    MainActivity sendData;
 
    public static ReproductionFragment newInstance()
    {
        return (new ReproductionFragment());
    }
 
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
    {
        View rootView = inflater.inflate(R.layout.fragment_reproduction, container, false);
 
        btnReprod = (Button) rootView.findViewById(R.id.fragment_reprod_btn_reprod);
        //mBluetoothConnection.startClient(mBluetoothConnection.mmDevice, MY_UUID_INSECURE);
 
        btnReprod.setOnClickListener(new View.OnClickListener()
        {
            @Override
            public void onClick(View view)
            {
                String msg = "bp_reprod";
                byte[] bytes = msg.getBytes(Charset.defaultCharset());
                try
                {
                    mBluetoothConnection.write(bytes);
                }
                catch (NullPointerException e)
                {
                    e.printStackTrace();
                }
            }
        });
 
        return rootView;
    }
}

Et voici les erreurs que je reçois:

Code :

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03-19 12:49:21.399 26997-26997/com.gxabt.uliege.microspectro_v1 W/System.err: java.lang.NullPointerException
03-19 12:49:21.429 26997-26997/com.gxabt.uliege.microspectro_v1 W/System.err:     at com.gxabt.uliege.microspectro_v1.Controllers.Fragments.ReproductionFragment$1.onClick(ReproductionFragment.java:49)
03-19 12:49:21.429 26997-26997/com.gxabt.uliege.microspectro_v1 W/System.err:     at android.view.View.performClick(View.java:4147)
03-19 12:49:21.429 26997-26997/com.gxabt.uliege.microspectro_v1 W/System.err:     at android.view.View$PerformClick.run(View.java:17161)
03-19 12:49:21.429 26997-26997/com.gxabt.uliege.microspectro_v1 W/System.err:     at android.os.Handler.handleCallback(Handler.java:615)
03-19 12:49:21.439 26997-26997/com.gxabt.uliege.microspectro_v1 W/System.err:     at android.os.Handler.dispatchMessage(Handler.java:92)
03-19 12:49:21.439 26997-26997/com.gxabt.uliege.microspectro_v1 W/System.err:     at android.os.Looper.loop(Looper.java:213)
03-19 12:49:21.439 26997-26997/com.gxabt.uliege.microspectro_v1 W/System.err:     at android.app.ActivityThread.main(ActivityThread.java:4786)
03-19 12:49:21.439 26997-26997/com.gxabt.uliege.microspectro_v1 W/System.err:     at java.lang.reflect.Method.invokeNative(Native Method)
03-19 12:49:21.439 26997-26997/com.gxabt.uliege.microspectro_v1 W/System.err:     at java.lang.reflect.Method.invoke(Method.java:511)
03-19 12:49:21.439 26997-26997/com.gxabt.uliege.microspectro_v1 W/System.err:     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:789)
03-19 12:49:21.439 26997-26997/com.gxabt.uliege.microspectro_v1 W/System.err:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:556)
03-19 12:49:21.439 26997-26997/com.gxabt.uliege.microspectro_v1 W/System.err:     at dalvik.system.NativeStart.main(Native Method)

Pouvez-Vous m'aider avec ce problème ?

Merci

**Drowan** · 19/03/2018, 15h08

Dans ta classe ReproductionFragment, tu as un attribut mBluetoothConnection que tu n'initialise jamais. Il est donc null. Ainsi quand à la ligne 49 de cette callse tu fais mBluetoothConnection.write(bytes);, java ne connait pas la methode write sur l'objet null (normal), Donc il te donne cette erreur.

**k.bertrand** · 19/03/2018, 15h19

Oui c'est vrai. Donc je dois refaire un truc du genre "mBluetoothConnection = new BluetoothConnectionService(getActivity)" ? Mais alors il faut aussi que je lui passe le nom du device et le uuid ?

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