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Editorial Team
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Asked: 2026-06-13T14:06:50+00:00

I am currently working on an android project and that has a user interface

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I am currently working on an android project and that has a user interface to configure a background service.

I have successfully opened and modified the values within the apps preference file but I am then trying to open the shared preference file within the service class but I am getting a null pointer exception.

I’m using the following code to open the file

SharedPreferences settings = this.getSharedPreferences("prefs", 0);

I’m then accessing the shared prefs using the following but when I debug I don’t think it gets this far, I think it fails on the line above.

if (isPowerConnected() && !wakeLock.isHeld() && settings.getBoolean("appEnabled", true))

Below is the exception that is thrown.

10-28 01:02:37.453: E/EnableWakeLock(18665): java.lang.NullPointerException
10-28 01:02:37.453: W/System.err(18665): java.lang.NullPointerException
10-28 01:02:37.453: W/System.err(18665):    at android.content.ContextWrapper.getSharedPreferences(ContextWrapper.java:153)

Thanks for any help you can provide.

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1 Answer

  1. Editorial Team

    Since you try to read a SharedPreferences from a Service you should read it via 

    PreferenceManager.getDefaultSharedPreferences()

    instead of 

    this.getSharedPreferences()

    getDefaultSharedPreferences() takes a Context – your Service as a parameter. Please refer to the documentation http://developer.android.com/reference/android/preference/PreferenceManager.html#getDefaultSharedPreferences%28android.content.Context

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