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androidbluetooth-lowenergydevicenetwork-scan

Android listing BLE devices after device scan


Can u provide me the simple code for scanning the nearby BLE devices and list it by device name and MAC ID. I tried this using sample code provided in http://developer.android.com/guide/topics/connectivity/bluetooth-le.html. But didn't work, any reference link or ideas since i am new to BLE app.


Solution

  • This example is based on the developers web you posted and works great for me. This is the code:

    DeviceScanActivity.class

    package com.example.android.bluetoothlegatt;
    
    import android.app.Activity;
    import android.app.ListActivity;
    import android.bluetooth.BluetoothAdapter;
    import android.bluetooth.BluetoothDevice;
    import android.bluetooth.BluetoothManager;
    import android.content.Context;
    import android.content.Intent;
    import android.content.pm.PackageManager;
    import android.os.Bundle;
    import android.os.Handler;
    import android.view.LayoutInflater;
    import android.view.Menu;
    import android.view.MenuItem;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.BaseAdapter;
    import android.widget.ListView;
    import android.widget.TextView;
    import android.widget.Toast;
    import java.util.ArrayList;
    
    public class DeviceScanActivity extends ListActivity {
    private LeDeviceListAdapter mLeDeviceListAdapter;
    private BluetoothAdapter mBluetoothAdapter;
    private boolean mScanning;
    private Handler mHandler;
    
    private static final int REQUEST_ENABLE_BT = 1;
    // Stops scanning after 10 seconds.
    private static final long SCAN_PERIOD = 10000;
    
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        getActionBar().setTitle(R.string.title_devices);
        mHandler = new Handler();
    
        // Use this check to determine whether BLE is supported on the device.  Then you can
        // selectively disable BLE-related features.
        if (!getPackageManager().hasSystemFeature(PackageManager.FEATURE_BLUETOOTH_LE)) {
            Toast.makeText(this, R.string.ble_not_supported, Toast.LENGTH_SHORT).show();
            finish();
        }
        // Initializes a Bluetooth adapter.  For API level 18 and above, get a reference to
        // BluetoothAdapter through BluetoothManager.
        final BluetoothManager bluetoothManager =
                (BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE);
        mBluetoothAdapter = bluetoothManager.getAdapter();
        // Checks if Bluetooth is supported on the device.
        if (mBluetoothAdapter == null) {
            Toast.makeText(this, R.string.error_bluetooth_not_supported, Toast.LENGTH_SHORT).show();
            finish();
            return;
        }
    }
    
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.main, menu);
        if (!mScanning) {
            menu.findItem(R.id.menu_stop).setVisible(false);
            menu.findItem(R.id.menu_scan).setVisible(true);
            menu.findItem(R.id.menu_refresh).setActionView(null);
        } else {
            menu.findItem(R.id.menu_stop).setVisible(true);
            menu.findItem(R.id.menu_scan).setVisible(false);
            menu.findItem(R.id.menu_refresh).setActionView(
                    R.layout.actionbar_indeterminate_progress);
        }
        return true;
    }
    
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            case R.id.menu_scan:
                mLeDeviceListAdapter.clear();
                scanLeDevice(true);
                break;
            case R.id.menu_stop:
                scanLeDevice(false);
                break;
        }
        return true;
    }
    
    @Override
    protected void onResume() {
        super.onResume();
        // Ensures Bluetooth is enabled on the device.  If Bluetooth is not currently enabled,
        // fire an intent to display a dialog asking the user to grant permission to enable it.
        if (!mBluetoothAdapter.isEnabled()) {
            Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
            startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT);
        }
        // Initializes list view adapter.
        mLeDeviceListAdapter = new LeDeviceListAdapter();
        setListAdapter(mLeDeviceListAdapter);
        scanLeDevice(true);
    }
    
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        // User chose not to enable Bluetooth.
        if (requestCode == REQUEST_ENABLE_BT && resultCode == Activity.RESULT_CANCELED) {
            finish();
            return;
        }
        super.onActivityResult(requestCode, resultCode, data);
    }
    
    @Override
    protected void onPause() {
        super.onPause();
        scanLeDevice(false);
        mLeDeviceListAdapter.clear();
    }
    
    private void scanLeDevice(final boolean enable) {
        if (enable) {
            // Stops scanning after a pre-defined scan period.
            mHandler.postDelayed(new Runnable() {
                @Override
                public void run() {
                    mScanning = false;
                    mBluetoothAdapter.stopLeScan(mLeScanCallback);
                    invalidateOptionsMenu();
                }
            }, SCAN_PERIOD);
            mScanning = true;
            mBluetoothAdapter.startLeScan(mLeScanCallback);
        } else {
            mScanning = false;
            mBluetoothAdapter.stopLeScan(mLeScanCallback);
        }
        invalidateOptionsMenu();
    }
    
    // Adapter for holding devices found through scanning.
    private class LeDeviceListAdapter extends BaseAdapter {
        private ArrayList<BluetoothDevice> mLeDevices;
        private LayoutInflater mInflator;
    
        public LeDeviceListAdapter() {
            super();
            mLeDevices = new ArrayList<BluetoothDevice>();
            mInflator = DeviceScanActivity.this.getLayoutInflater();
        }
    
        public void addDevice(BluetoothDevice device) {
            if(!mLeDevices.contains(device)) {
                mLeDevices.add(device);
            }
        }
    
        public BluetoothDevice getDevice(int position) {
            return mLeDevices.get(position);
        }
    
        public void clear() {
            mLeDevices.clear();
        }
    
        @Override
        public int getCount() {
            return mLeDevices.size();
        }
    
        @Override
        public Object getItem(int i) {
            return mLeDevices.get(i);
        }
    
        @Override
        public long getItemId(int i) {
            return i;
        }
    
        @Override
        public View getView(int i, View view, ViewGroup viewGroup) {
            ViewHolder viewHolder;
            // General ListView optimization code.
            if (view == null) {
                view = mInflator.inflate(R.layout.listitem_device, null);
                viewHolder = new ViewHolder();
                viewHolder.deviceAddress = (TextView) view.findViewById(R.id.device_address);
                viewHolder.deviceName = (TextView) view.findViewById(R.id.device_name);
                view.setTag(viewHolder);
            } else {
                viewHolder = (ViewHolder) view.getTag();
            }
    
            BluetoothDevice device = mLeDevices.get(i);
            final String deviceName = device.getName();
            if (deviceName != null && deviceName.length() > 0)
                viewHolder.deviceName.setText(deviceName);
            else
                viewHolder.deviceName.setText(R.string.unknown_device);
            viewHolder.deviceAddress.setText(device.getAddress());
    
            return view;
        }
    }
    
    // Device scan callback.
    private BluetoothAdapter.LeScanCallback mLeScanCallback =
            new BluetoothAdapter.LeScanCallback() {
    
        @Override
        public void onLeScan(final BluetoothDevice device, int rssi, byte[] scanRecord) {
            runOnUiThread(new Runnable() {
                @Override
                public void run() {
                    mLeDeviceListAdapter.addDevice(device);
                    mLeDeviceListAdapter.notifyDataSetChanged();
                }
            });
        }
    };
    
    static class ViewHolder {
        TextView deviceName;
        TextView deviceAddress;
    }
    

    }

    The custom layout for the Listview listitem_device.xml :

    <?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:orientation="vertical"
              android:layout_width="match_parent"
              android:layout_height="wrap_content">
      <TextView android:id="@+id/device_name"
              android:layout_width="match_parent"
              android:layout_height="wrap_content"
              android:textSize="24dp"/>
      <TextView android:id="@+id/device_address"
              android:layout_width="match_parent"
              android:layout_height="wrap_content"
              android:textSize="12dp"/>
    </LinearLayout>
    

    The progress bar on scanning actionbar_indeterminate_progress.xml :

    <FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
             android:layout_height="wrap_content"
             android:layout_width="56dp"
             android:minWidth="56dp">
    <ProgressBar android:layout_width="32dp"
                 android:layout_height="32dp"
                 android:layout_gravity="center"/>
    </FrameLayout>
    

    The menu layout main.xml :

    <?xml version="1.0" encoding="utf-8"?>
    <menu xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:id="@+id/menu_refresh"
          android:checkable="false"
          android:orderInCategory="1"
          android:showAsAction="ifRoom"/>
    <item android:id="@+id/menu_scan"
          android:title="@string/menu_scan"
          android:orderInCategory="100"
          android:showAsAction="ifRoom|withText"/>
    <item android:id="@+id/menu_stop"
          android:title="@string/menu_stop"
          android:orderInCategory="101"
          android:showAsAction="ifRoom|withText"/>
    </menu>
    

    The strings layout strings.xml :

    <?xml version="1.0" encoding="utf-8"?>
    <resources>
      <string name="ble_not_supported">BLE is not supported</string>
      <string name="error_bluetooth_not_supported">Bluetooth not supported.</string>
      <string name="unknown_device">Unknown device</string>
    
      <!-- Menu items -->
      <string name="menu_connect">Connect</string>
      <string name="menu_disconnect">Disconnect</string>
      <string name="menu_scan">Scan</string>
      <string name="menu_stop">Stop</string>
    </resources>
    

    And the manifest AndroidManifest.xml :

    <?xml version="1.0" encoding="UTF-8"?>
    <manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.android.bluetoothlegatt"
    android:versionCode="1"
    android:versionName="1.0">
    
    <uses-sdk android:minSdkVersion="18"
        android:targetSdkVersion="19"/>
    <uses-feature android:name="android.hardware.bluetooth_le" android:required="true"/>
    
    <uses-permission android:name="android.permission.BLUETOOTH"/>
    <uses-permission android:name="android.permission.BLUETOOTH_ADMIN"/>
    
    <application android:label="@string/app_name"
        android:icon="@drawable/ic_launcher"
        android:theme="@android:style/Theme.Holo.Light">
        <activity android:name=".DeviceScanActivity"
            android:label="@string/app_name">
            <intent-filter>
                <action android:name="android.intent.action.MAIN"/>
                <category android:name="android.intent.category.LAUNCHER"/>
            </intent-filter>
        </activity>
    </application>
    
    </manifest>
    

    I think this is all. If I missed anything let me now and I fix it. Hope it helps!!

    (Bluetooth LE quite sucks in Android yet :D... needs and update fast!)

    UPDATE:

    Check the full example of BLE scan and connection in GitHub: https://github.com/kodartcha/BLEDeviceScanSample