CODEWITHSUNDEEP
androidnullpointerexception
user874649
user874649

Reputation:

Android nullpointerexception

To be short...I have a widget, you can see the important part below

public class ExampleWidget extends AppWidgetProvider {
private PhoneStateListener listener;
private TelephonyManager telephonyManager;

@Override
public void onUpdate(Context context, AppWidgetManager appWidgetManager,
        int[] appWidgetIds) {

    listener = new PhoneStateListener() {
        @Override
        public void onDataConnectionStateChanged(int state) {
            // removed the code
        }

    };

    telephonyManager = (TelephonyManager) context
            .getSystemService(Context.TELEPHONY_SERVICE);
    telephonyManager.listen(listener,
            PhoneStateListener.LISTEN_DATA_CONNECTION_STATE);

}

@Override
public void onDisabled(Context context) {
    telephonyManager.listen(listener, PhoneStateListener.LISTEN_NONE);
    super.onDisabled(context);
}
}

and I am receiving nullpointer exception at telephonyManager.listen(listener, PhoneStateListener.LISTEN_NONE); when I am removing the widget from the main screen.

What am I missing?

Upvotes: 2

Views: 2381

Answers (4)

Vadim
Vadim

Reputation: 1602

I got same probem. Actually problem disapeared after I made all null fields static. Looks like it;s really another instance of provider who gets onDisabled.

Upvotes: 0

fyr
fyr

Reputation: 20859

context.getSystemService() may return null and you do not prove telephonyManager if it is null. If the name identified by Context.TELEPHONY_SERVICE does not exist in the system the telephonyManager will be null.

In addition to your comment:

@Override
public void onDisabled(Context context) {
    if (telephonyManager!=null){
        telephonyManager.listen(listener, PhoneStateListener.LISTEN_NONE);
    }
    super.onDisabled(context);
}

If you need to run this code in the onDisabled Method you should initialize the telephonyManager. It smells like the onDisabled method is called somehow before onUpdate or if you have two different instances.

Upvotes: 2

Jett Hsieh
Jett Hsieh

Reputation: 3159

Just check telephonyManager to see if it is null.

if(telephonyManager==null){
    telephonyManager = (TelephonyManager) context
        .getSystemService(Context.TELEPHONY_SERVICE);
}
telephonyManager.listen(listener, PhoneStateListener.LISTEN_NONE);

Upvotes: 0

jainal
jainal

Reputation: 3021

public class ExampleWidget extends AppWidgetProvider {
private PhoneStateListener listener;
private TelephonyManager telephonyManager;

@Override
public void onUpdate(Context context, AppWidgetManager appWidgetManager,
        int[] appWidgetIds) {


    telephonyManager = (TelephonyManager) context
            .getSystemService(Context.TELEPHONY_SERVICE);
    telephonyManager.listen(listener,
            PhoneStateListener.LISTEN_DATA_CONNECTION_STATE);

}

@Override
public void onDisabled(Context context) {
    telephonyManager.listen(listener, PhoneStateListener.LISTEN_NONE);
    super.onDisabled(context);
}
listener = new PhoneStateListener() {
        @Override
        public void onDataConnectionStateChanged(int state) {
            // removed the code
        }

    };

}

Upvotes: 0

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