Scan Bluetooth Devices

To start scan bluetooth device, simple call bluetoothAdapter.startDiscovery().

In order to receive the list of found bluetooth devices, we have to implement a BroadcastReceiver for BluetoothDevice.ACTION_FOUND.



AndroidBluetooth.java

package com.exercise.AndroidBluetooth;

import android.app.Activity;
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.Bundle;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.TextView;

public class AndroidBluetooth extends Activity {

private static final int REQUEST_ENABLE_BT = 1;

ListView listDevicesFound;
Button btnScanDevice;
TextView stateBluetooth;
BluetoothAdapter bluetoothAdapter;

ArrayAdapter<String> btArrayAdapter;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);

btnScanDevice = (Button)findViewById(R.id.scandevice);

stateBluetooth = (TextView)findViewById(R.id.bluetoothstate);
bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();

listDevicesFound = (ListView)findViewById(R.id.devicesfound);
btArrayAdapter = new ArrayAdapter<String>(AndroidBluetooth.this, android.R.layout.simple_list_item_1);
listDevicesFound.setAdapter(btArrayAdapter);

CheckBlueToothState();

btnScanDevice.setOnClickListener(btnScanDeviceOnClickListener);

registerReceiver(ActionFoundReceiver, 
new IntentFilter(BluetoothDevice.ACTION_FOUND));
}

@Override
protected void onDestroy() {
// TODO Auto-generated method stub
super.onDestroy();
unregisterReceiver(ActionFoundReceiver);
}

private void CheckBlueToothState(){
if (bluetoothAdapter == null){
stateBluetooth.setText("Bluetooth NOT support");
}else{
if (bluetoothAdapter.isEnabled()){
if(bluetoothAdapter.isDiscovering()){
stateBluetooth.setText("Bluetooth is currently in device discovery process.");
}else{
stateBluetooth.setText("Bluetooth is Enabled.");
btnScanDevice.setEnabled(true);
}
}else{
stateBluetooth.setText("Bluetooth is NOT Enabled!");
Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT);
}
}
}

private Button.OnClickListener btnScanDeviceOnClickListener
= new Button.OnClickListener(){

@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
btArrayAdapter.clear();
bluetoothAdapter.startDiscovery();
}};

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
// TODO Auto-generated method stub
if(requestCode == REQUEST_ENABLE_BT){
CheckBlueToothState();
}
}

private final BroadcastReceiver ActionFoundReceiver = new BroadcastReceiver(){

@Override
public void onReceive(Context context, Intent intent) {
// TODO Auto-generated method stub
String action = intent.getAction();
if(BluetoothDevice.ACTION_FOUND.equals(action)) {
BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
btArrayAdapter.add(device.getName() + "\n" + device.getAddress());
btArrayAdapter.notifyDataSetChanged();
}
}};

}

main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<TextView  
android:layout_width="fill_parent" 
android:layout_height="wrap_content" 
android:text="@string/hello"
/>
<TextView 
android:id="@+id/bluetoothstate" 
android:layout_width="fill_parent" 
android:layout_height="wrap_content" 
/>
<TextView
android:id="@+id/bluetoothstate" 
android:layout_width="fill_parent" 
android:layout_height="wrap_content" 
/>
<TextView
android:layout_width="fill_parent" 
android:layout_height="wrap_content" 
android:text="Set Discoverable Duration" 
/>
<Button
android:id="@+id/scandevice" 
android:layout_width="fill_parent" 
android:layout_height="wrap_content"
android:text="Scan Bluetooth Devices" 
android:enabled="false"
/> 
<ListView
android:id="@+id/devicesfound" 
android:layout_width="fill_parent" 
android:layout_height="fill_parent"
/> 
</LinearLayout>

Modify AndroidManifest.xml to grant permission of "android.permission.BLUETOOTH", and "android.permission.BLUETOOTH_ADMIN".

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.exercise.AndroidBluetooth"
android:versionCode="1"
android:versionName="1.0">
<uses-sdk android:minSdkVersion="7" />
<uses-permission android:name="android.permission.BLUETOOTH"></uses-permission>
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN"></uses-permission>

<application android:icon="@drawable/icon" android:label="@string/app_name">
<activity android:name=".AndroidBluetooth"
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>

Download the files.


Related:
- Start Bluetooth Discoverable and register BroadcastReceiver for ACTION_SCAN_MODE_CHANGED