Re: [android-developers] Re: Hello Everyone, i just have a quick question:

Uhm....the "root" of the error is at that line 87 of your BTD...Activity.

What's at that line?

is it: Set<BluetoothDevice> pairedDevices = mBtAdapter.getBondedDevices(); ?

ant it might be that mBtAdapter is null (by reading the docs it says that BluetoothAdapter.getDefaultAdapter() returns null when bluetooth is not supported -  http://developer.android.com/reference/android/bluetooth/BluetoothAdapter.html#getDefaultAdapter() ).

Maybe you are using the emulator to run this? (AFAIK the emulator doesn't support bluetooth)

so, just add a if (mBtAdapter != null) { ... rest of your code .. }

On Sat, Feb 25, 2012 at 10:19 PM, Mohamed Gougam <mblackpnk@gmail.com> wrote:

Hello,

You mean this part of the log:

 "02-23 18:35:35.985: E/AndroidRuntime(228): Caused by: java.lang.NullPointerException

02-23 18:35:35.985: E/AndroidRuntime(228):  at android.mgo.helloandroid.BTDdetecetwithV7Activity.onCreate(BTDdetecetwithV7Activity.java:87)"

The program doesn't stop at that point !!

i was looking at this one:

"02-23 18:35:35.985: E/AndroidRuntime(228): java.lang.RuntimeException: Unable to start activity ComponentInfo{android.mgo.helloandroid/android.mgo.helloandroid.BTDdetecetwithV7Activity}: java.lang.NullPointerException"

On Sat, Feb 25, 2012 at 11:43 PM, YuviDroid <yuvidroid@gmail.com> wrote:

As the log suggests the NullPointerException occurs at line 87 of BTDdetecetwithV7Activity.java.

Take a look at that line and see what might be wrong..

On Sat, Feb 25, 2012 at 8:21 PM, Mohamed Gougam <mblackpnk@gmail.com> wrote:

Hello, 

I used The Log.e and Log.d in many places in the code including in the onCreate method and i found that the error is there and it's not going any further beyond it...

Still don't know what's wrong though.

On Thu, Feb 23, 2012 at 11:40 PM, Mohamed Gougam <mblackpnk@gmail.com> wrote:

Hello Moktarul, sorry for the late reply, i was playing around with the onCreate since you said you think that the source of the bug most probably is onCreate method, well i am putting the Logcat error messages and Activity code bellow,

LogCat:

02-23 18:35:35.935: D/AndroidRuntime(228): Shutting down VM

02-23 18:35:35.946: W/dalvikvm(228): threadid=3: thread exiting with uncaught exception (group=0x4001b188)

02-23 18:35:35.946: E/AndroidRuntime(228): Uncaught handler: thread main exiting due to uncaught exception

02-23 18:35:35.985: E/AndroidRuntime(228): java.lang.RuntimeException: Unable to start activity ComponentInfo{android.mgo.helloandroid/android.mgo.helloandroid.BTDdetecetwithV7Activity}: java.lang.NullPointerException

02-23 18:35:35.985: E/AndroidRuntime(228): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2496)

02-23 18:35:35.985: E/AndroidRuntime(228): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2512)

02-23 18:35:35.985: E/AndroidRuntime(228): at android.app.ActivityThread.access$2200(ActivityThread.java:119)

02-23 18:35:35.985: E/AndroidRuntime(228): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1863)

02-23 18:35:35.985: E/AndroidRuntime(228): at android.os.Handler.dispatchMessage(Handler.java:99)

02-23 18:35:35.985: E/AndroidRuntime(228): at android.os.Looper.loop(Looper.java:123)

02-23 18:35:35.985: E/AndroidRuntime(228): at android.app.ActivityThread.main(ActivityThread.java:4363)

02-23 18:35:35.985: E/AndroidRuntime(228): at java.lang.reflect.Method.invokeNative(Native Method)

02-23 18:35:35.985: E/AndroidRuntime(228): at java.lang.reflect.Method.invoke(Method.java:521)

02-23 18:35:35.985: E/AndroidRuntime(228): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)

02-23 18:35:35.985: E/AndroidRuntime(228): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)

02-23 18:35:35.985: E/AndroidRuntime(228): at dalvik.system.NativeStart.main(Native Method)

02-23 18:35:35.985: E/AndroidRuntime(228): Caused by: java.lang.NullPointerException

02-23 18:35:35.985: E/AndroidRuntime(228): at android.mgo.helloandroid.BTDdetecetwithV7Activity.onCreate(BTDdetecetwithV7Activity.java:87)

02-23 18:35:35.985: E/AndroidRuntime(228): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)

02-23 18:35:35.985: E/AndroidRuntime(228): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2459)

02-23 18:35:35.985: E/AndroidRuntime(228): ... 11 more

02-23 18:35:36.015: I/dalvikvm(228): threadid=7: reacting to signal 3

02-23 18:35:36.065: I/dalvikvm(228): Wrote stack trace to '/data/anr/traces.txt'

The Activity:

package android.mgo.helloandroid;

import java.util.Set;

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.util.Log;

import android.view.View;

import android.view.View.OnClickListener;

import android.view.Window;

import android.widget.ArrayAdapter;

import android.widget.Button;

import android.widget.ListView;

public class BTDdetecetwithV7Activity extends Activity  {

    /** Called when the activity is first created. */

    // Debugging

    private static final String TAG = "DeviceListActivity";

    private static final boolean D = true;

    // Return Intent extra

    public static String EXTRA_DEVICE_ADDRESS = "device_address";

    // Member fields

    private BluetoothAdapter mBtAdapter;

    private ArrayAdapter<String> mPairedDevicesArrayAdapter;

    private ArrayAdapter<String> mNewDevicesArrayAdapter;

    @Override

    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        

        // Setup the window

        requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS);

        setContentView(R.layout.main);

        

        // Set result CANCELED in case the user backs out

        setResult(Activity.RESULT_CANCELED);

        

        // Initialize the button to perform device discovery

        Button scanButton = (Button) findViewById(R.id.button_scan);

        scanButton.setOnClickListener(new OnClickListener() {

            public void onClick(View v) {

                doDiscovery();

                v.setVisibility(View.GONE);

            }

        });

        // Initialize array adapters. One for already paired devices and

        // one for newly discovered devices

        mPairedDevicesArrayAdapter = new ArrayAdapter<String>(this, R.layout.main);

        mNewDevicesArrayAdapter = new ArrayAdapter<String>(this, R.layout.main);

        

        // Find and set up the ListView for paired devices

        ListView pairedListView = (ListView) findViewById(R.id.paired_devices);

        pairedListView.setAdapter(mPairedDevicesArrayAdapter);

        

        // Find and set up the ListView for newly discovered devices

        ListView newDevicesListView = (ListView) findViewById(R.id.new_devices);

        newDevicesListView.setAdapter(mNewDevicesArrayAdapter);

        // Register for broadcasts when a device is discovered

        IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_FOUND);

        this.registerReceiver(mReceiver, filter);

        // Register for broadcasts when discovery has finished

        filter = new IntentFilter(BluetoothAdapter.ACTION_DISCOVERY_FINISHED);

        this.registerReceiver(mReceiver, filter);

        // Get the local Bluetooth adapter

        mBtAdapter = BluetoothAdapter.getDefaultAdapter();

        

        // Get a set of currently paired devices

        Set<BluetoothDevice> pairedDevices = mBtAdapter.getBondedDevices();

        

        

        // If there are paired devices, add each one to the ArrayAdapter

        if (pairedDevices.size() > 0) {

            findViewById(R.id.title_paired_devices).setVisibility(View.VISIBLE);

            

            for (BluetoothDevice device : pairedDevices) {

                mPairedDevicesArrayAdapter.add(device.getName() + "\n" + device.getAddress());

            }

            

        } else {

            String noDevices = getResources().getText(R.string.none_paired).toString();

            mPairedDevicesArrayAdapter.add(noDevices);

        }

    }

    

    @Override

    protected void onDestroy() {

        super.onDestroy();

        

        // Make sure we're not doing discovery anymore

        if (mBtAdapter != null) {

            mBtAdapter.cancelDiscovery();

        }

        

        // Unregister broadcast listeners

        this.unregisterReceiver(mReceiver);

    }

        

    /**

     * Start device discover with the BluetoothAdapter

     */

    private void doDiscovery() {

        if (D) Log.d(TAG, "doDiscovery()");

        

        // Indicate scanning in the title

        setProgressBarIndeterminateVisibility(true);

        setTitle(R.string.scanning);

        

        // Turn on sub-title for new devices

        findViewById(R.id.title_new_devices).setVisibility(View.VISIBLE);

        // If we're already discovering, stop it

        if (mBtAdapter.isDiscovering()) {

            mBtAdapter.cancelDiscovery();

        }

        

        

        // Request discover from BluetoothAdapter

        mBtAdapter.startDiscovery();

    }

        // The BroadcastReceiver that listens for discovered devices and

        // changes the title when discovery is finished

        private final BroadcastReceiver mReceiver = new BroadcastReceiver() {

            @Override

            public void onReceive(Context context, Intent intent) {

                String action = intent.getAction();

    

    

            // When discovery finds a device

            if (BluetoothDevice.ACTION_FOUND.equals(action)) {

                // Get the BluetoothDevice object from the Intent

                BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);

                // If it's already paired, skip it, because it's been listed already

                if (device.getBondState() != BluetoothDevice.BOND_BONDED) {

                    mNewDevicesArrayAdapter.add(device.getName() + "\n" + device.getAddress());

                }

      

            } else if (BluetoothAdapter.ACTION_DISCOVERY_FINISHED.equals(action)) {

                setProgressBarIndeterminateVisibility(false);

                setTitle(R.string.select_device);

                if (mNewDevicesArrayAdapter.getCount() == 0) {

                    String noDevices = getResources().getText(R.string.none_found).toString();

                    mNewDevicesArrayAdapter.add(noDevices);

                }

            }

        }

    };

}

        

    

On Thu, Feb 23, 2012 at 9:27 AM, moktarul anam <moktarul@gmail.com> wrote:

can u please send me ur activity code and little more log message

Moktarul anam

On Feb 23, 10:18 am, moktarul anam <mokta...@gmail.com> wrote:
> Hi Soyer,
>
> I think problem is in ur oncreate or onstart method.  can u please do
> that ...
> remove all code from oncreate and check
>
> Can u please send little more log
> Moktarul
>
> On Feb 22, 11:42 pm, Mohamed Gougam <mblack...@gmail.com> wrote:
>
>
>
>
>
>
>
> > Hello moktarul, the thing about manifest.xml, is tht i have only one
> > activity so nothing to get confused with. the manifest file is bellow:
>
> > <?xml version="1.0" encoding="utf-8"?>
> > <manifest xmlns:android="http://schemas.android.com/apk/res/android"
> >     package="android.mgo.helloandroid"
> >     android:versionCode="1"
> >     android:versionName="1.0" >
>
> >     <uses-sdk android:minSdkVersion="7" />
>
> >     <application
> >         android:icon="@drawable/ic_launcher"
> >         android:label="@string/app_name" >
> >         <activity
> >             android:label="@string/app_name"
> >             android:name=".BTDdetecetwithV7Activity">
> >             <intent-filter>
> >                 <action android:name="android.intent.action.MAIN"/>
>
> >                 <category android:name="android.intent.category.LAUNCHER"/>
> >             </intent-filter>
> >         </activity>
> >     </application>
> >             <uses-permission android:name="android.permission.BLUETOOTH"/>
> >             <uses-permission
> > android:name="android.permission.BLUETOOTH_ADMIN"/>
> > </manifest>
>
> > On Wed, Feb 22, 2012 at 1:04 AM, Mohamed Gougam <mblack...@gmail.com> wrote:
> > > Hello  moktarul,
>
> > > Thanks alot, i will do that, and let you know :)
>
> > > On Tue, Feb 21, 2012 at 12:10 PM, moktarul anam <mokta...@gmail.com>wrote:
>
> > >> sorry, its Activity Intent filter not internt filter
> > >> Moktarul
>
> > >> On Feb 21, 12:42 pm, moktarul anam <mokta...@gmail.com> wrote:
> > >> > Hi Soyer,
> > >> > All your activity class has to be there in your Manifest.xml file
>
> > >> > if you call your activity class from other activity then that class
> > >> > has to be main( internt filter main) Please check these two point and
> > >> > i think this will solve ur problem.
> > >> > I am sure some problem in ur Manifest.xml file
>
> > >> > Moktarul
>
> > >> > On Feb 20, 11:24 pm, Mohamed Gougam <mblack...@gmail.com> wrote:
>
> > >> > > Hi Moktarul, What is in the the manifest file, you mean i have to
> > >> remove
> > >> > > the "." ? i don't think that's it, the "." has to be there.
>
> > >> > > Thanks guys for the help, Kris is it wrong if somebody try to learn
> > >> > > something different, out of his field !! Thanks for the help though i
> > >> > > really appreciate it.
>
> > >> > > On Mon, Feb 20, 2012 at 3:44 PM, moktarul anam <mokta...@gmail.com>
> > >> wrote:
> > >> > > > Hi
> > >> > > > BTDdetecetwithV7Activity in ur android  Manifest file
> > >> > > > <activity name="BTDdetecetwithV7Activity"/>\
>
> > >> > > > Enjoy
> > >> > > > moktarul
>
> > >> > > > On Feb 20, 12:26 am, Soyer <mblack...@gmail.com> wrote:
> > >> > > > > Hello everyone, Can anyone explain to me what this following error
> > >> > > > > means? have anyone faced the same?
>
> > >> > > > > ERROR:
>
> > >> > > > > 02-19 18:10:41.321: E/AndroidRuntime(319):
> > >> java.lang.RuntimeException:
> > >> > > > > Unable to start activity ComponentInfo{android.mgo.helloandroid/
> > >> > > > > android.mgo.helloandroid.BTDdetecetwithV7Activity}:
> > >> > > > > java.lang.NullPointerException
>
> > >> > > > --
> > >> > > > You received this message because you are subscribed to the Google
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