Unable to obtain bluetooth adapter

[Renjith Mohan]

Hi all,
I am writing a small bluetooth application to search for devices. However, the bluetooth adapter instance is always null. See the code below.

public class BluetoothDemo extends Activity {

	TextView out;
	public void onCreate(Bundle savedState) {
		super.onCreate(savedState);
		setContentView(R.layout.scanned_devices);
		
		BluetoothAdapter adapter = BluetoothAdapter.getDefaultAdapter();
		
		if (adapter == null) {
			//Alert user that the device does not support bluetooth
			Log.d("", "bluetooth adapter is not available.");
			this.finish();
		}
		
		if(null!= adapter) {
			Log.i("", "bluetooth adapter found..." + adapter);
		}
		//Enabling bluetooth 
		if (!adapter.isEnabled()) {
			Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
		    startActivityForResult(enableBtIntent, 0);
		}
         }
    }

And the manifest file is

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="com.android.app"
      android:versionCode="1"
      android:versionName="1.0">
    <uses-sdk android:minSdkVersion="9" />

	<uses-permission android:name="android.permission.BLUETOOTH" />
    <uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
     
    <application android:icon="@drawable/icon" android:label="@string/app_name">
        <activity android:name=".UserMain"
                  android:label="@string/app_name">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
		<activity android:name=".SimpleExample"
		 		  android:label="@string/app_name">
		 	<intent-filter>
		 		<action android:name="android.intent.action.SimpleExample" />
		 		<category android:name="android.intent.category.DEFAULT" />
		 	</intent-filter>
		</activity>
		<activity android:name=".FileBrowser"
		 		  android:label="@string/app_name" />
		<activity android:name=".BluetoothDemo"
		 		  android:label="@string/app_name" />
    </application>
     
     
</manifest>

Message in the LogCat is null pointer exception at line 20 (refer BluetoothDemo.java)

What could be the reason?

Thanks in advance!

--Renjith

[Peter Johnson]

Are you running this code on your phone or on the adapter? I don't think that the adapter has bluetooth.

Also, you code could use some rearranging - you check adapter for null twice while you you could check just once, and you should not use adapter (lines 20-22) unless it is non-null

[Renjith Mohan]

I tried running it on an emulator as well on the phone. Every time I try on the phone, it ends up with the message

The application has stopped unexpectedly. Please try later.

Yeah, i wrote it twice. it was a typo...the actual source has only one check.

[Renjith Mohan]

By the way, BluetoothAdapter class is used to check if bluetooth is supported in the device.