CODEWITHSUNDEEP
androidnullpointerexceptionsharedpreferencessocketexception
James
James

Reputation: 474

Android PreferenceManager NullPointException

I'm struggling to understand why I'm getting a null point exception when using PreferenceManager.

I'm using a button within the current activity to call another activity named Location

    /** Location selection */
    bLocation = (Button) findViewById(R.id.bLocation);
    bLocation.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {

            loc = new Location();
            loc.locationSelection();
        }
    });

// The button above calls the class below

public class Location extends Activity {

    NetworkConnection nc;
    SharedPreferences prefs;
    SharedPreferences sharedPrefs;
    NetworkConnection netConnect;
    Options opts;

    public void locationSelection(){

        try{
            sharedPrefs = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
            if (sharedPrefs.contains("LOCATION")){
                Log.d("if", "if");
            }else{
                Log.d("if", "else");

            }

        }catch(Exception e){
            Log.d("EXCEPTION", "Location Selection " + e);
        }
    }
}

EDIT:

//Entire Options class which class the Location class.

public class Options extends Activity {

    /** Include classes */
    SharedPreferences sharedPrefs;
    Preferences prefs;
    Location loc;
    LocationSQL locSQL;
    NetworkConnection netConnect;

    /** Declare buttons */
    Button bLocation;
    Button bRefresh;

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.options);

        sharedPrefs = PreferenceManager.getDefaultSharedPreferences(Options.this);

        /** Set the location for the user */
        setLocationPref();

        /** Refresh selection */
        bRefresh = (Button) findViewById(R.id.bRefresh);
        bRefresh.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {


            }
        });

        /** Location selection */
        bLocation = (Button) findViewById(R.id.bLocation);
        bLocation.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {

                loc = new Location();
                loc.locationSelection();
            }
        });
    }

//Entire log cat

06-10 13:56:03.015: D/AndroidRuntime(27310): >>>>>>>>>>>>>> AndroidRuntime START <<<<<<<<<<<<<<
06-10 13:56:03.015: D/AndroidRuntime(27310): CheckJNI is ON
06-10 13:56:03.135: D/AndroidRuntime(27310): --- registering native functions ---
06-10 13:56:03.685: D/dalvikvm(249): GC_EXPLICIT freed 88 objects / 4296 bytes in 43ms
06-10 13:56:03.726: D/PackageParser(59): Scanning package: /data/app/vmdl72287.tmp
06-10 13:56:03.845: I/PackageManager(59): Removing non-system package:com.swiftdrink
06-10 13:56:03.845: I/ActivityManager(59): Force stopping package com.swiftdrink uid=10036
06-10 13:56:03.855: I/Process(59): Sending signal. PID: 26952 SIG: 9
06-10 13:56:03.865: I/UsageStats(59): Unexpected resume of com.android.launcher while already resumed in com.swiftdrink
06-10 13:56:03.875: I/WindowManager(59): WIN DEATH: Window{44f77270 com.swiftdrink/com.swiftdrink.SwiftDrinkMain paused=false}
06-10 13:56:03.905: W/InputManagerService(59): Got RemoteException sending setActive(false) notification to pid 26952 uid 10036
06-10 13:56:04.016: W/IInputConnectionWrapper(114): showStatusIcon on inactive InputConnection
06-10 13:56:04.205: D/PackageManager(59): Scanning package com.swiftdrink
06-10 13:56:04.205: I/PackageManager(59): Package com.swiftdrink codePath changed from /data/app/com.swiftdrink-1.apk to /data/app/com.swiftdrink-2.apk; Retaining data and using new
06-10 13:56:04.215: I/PackageManager(59): /data/app/com.swiftdrink-2.apk changed; unpacking
06-10 13:56:04.225: D/installd(34): DexInv: --- BEGIN '/data/app/com.swiftdrink-2.apk' ---
06-10 13:56:04.435: D/dalvikvm(27317): DexOpt: load 36ms, verify 99ms, opt 2ms
06-10 13:56:04.445: D/installd(34): DexInv: --- END '/data/app/com.swiftdrink-2.apk' (success) ---
06-10 13:56:04.445: W/PackageManager(59): Code path for pkg : com.swiftdrink changing from /data/app/com.swiftdrink-1.apk to /data/app/com.swiftdrink-2.apk
06-10 13:56:04.445: W/PackageManager(59): Resource path for pkg : com.swiftdrink changing from /data/app/com.swiftdrink-1.apk to /data/app/com.swiftdrink-2.apk
06-10 13:56:04.455: D/PackageManager(59):   Activities: com.swiftdrink.SplashScreen com.swiftdrink.SwiftDrinkMain com.swiftdrink.Deals com.swiftdrink.Events com.swiftdrink.Featured com.swiftdrink.Options com.swiftdrink.SortBy com.swiftdrink.NetworkConnection com.swiftdrink.Constents com.swiftdrink.getSetLocation com.swiftdrink.Location com.swiftdrink.DBAdapter com.swiftdrink.JSON com.swiftdrink.Preferences
06-10 13:56:04.465: I/ActivityManager(59): Force stopping package com.swiftdrink uid=10036
06-10 13:56:04.565: I/installd(34): move /data/dalvik-cache/data@[email protected]@classes.dex -> /data/dalvik-cache/data@[email protected]@classes.dex
06-10 13:56:04.565: D/PackageManager(59): New package installed in /data/app/com.swiftdrink-2.apk
06-10 13:56:04.685: I/ActivityManager(59): Force stopping package com.swiftdrink uid=10036
06-10 13:56:04.835: D/dalvikvm(114): GC_EXPLICIT freed 1024 objects / 58032 bytes in 140ms
06-10 13:56:04.845: D/dalvikvm(59): GC_EXPLICIT freed 12088 objects / 692712 bytes in 141ms
06-10 13:56:05.015: W/RecognitionManagerService(59): no available voice recognition services found
06-10 13:56:05.235: D/dalvikvm(59): GC_EXPLICIT freed 4804 objects / 260184 bytes in 94ms
06-10 13:56:05.255: D/dalvikvm(148): GC_EXPLICIT freed 2567 objects / 129888 bytes in 540ms
06-10 13:56:05.265: I/installd(34): unlink /data/dalvik-cache/data@[email protected]@classes.dex
06-10 13:56:05.276: D/AndroidRuntime(27310): Shutting down VM
06-10 13:56:05.285: D/dalvikvm(27310): Debugger has detached; object registry had 1 entries
06-10 13:56:05.305: I/dalvikvm(27310): JNI: AttachCurrentThread (from ???.???)
06-10 13:56:05.305: I/AndroidRuntime(27310): NOTE: attach of thread 'Binder Thread #3' failed
06-10 13:56:05.786: D/AndroidRuntime(27322): >>>>>>>>>>>>>> AndroidRuntime START <<<<<<<<<<<<<<
06-10 13:56:05.786: D/AndroidRuntime(27322): CheckJNI is ON
06-10 13:56:05.895: D/AndroidRuntime(27322): --- registering native functions ---
06-10 13:56:06.466: I/ActivityManager(59): Starting activity: Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10000000 cmp=com.swiftdrink/.SplashScreen }
06-10 13:56:06.505: I/ActivityManager(59): Start proc com.swiftdrink for activity com.swiftdrink/.SplashScreen: pid=27328 uid=10036 gids={3003, 1015}
06-10 13:56:06.535: D/AndroidRuntime(27322): Shutting down VM
06-10 13:56:06.535: D/dalvikvm(27322): Debugger has detached; object registry had 1 entries
06-10 13:56:06.575: I/AndroidRuntime(27322): NOTE: attach of thread 'Binder Thread #3' failed
06-10 13:56:07.445: D/dalvikvm(27328): GC_EXTERNAL_ALLOC freed 858 objects / 59096 bytes in 175ms
06-10 13:56:07.815: I/ActivityManager(59): Displayed activity com.swiftdrink/.SplashScreen: 1333 ms (total 1333 ms)
06-10 13:56:08.155: I/ActivityManager(59): Starting activity: Intent { act=com.swiftdrink.SWIFTDRINKMAIN cmp=com.swiftdrink/.SwiftDrinkMain }
06-10 13:56:08.275: V/one(27328): locationSelection
06-10 13:56:08.585: I/ActivityManager(59): Displayed activity com.swiftdrink/.SwiftDrinkMain: 428 ms (total 428 ms)
06-10 13:56:11.646: D/SntpClient(59): request time failed: java.net.SocketException: Address family not supported by protocol
06-10 13:56:16.886: D/dalvikvm(114): GC_EXPLICIT freed 970 objects / 55696 bytes in 124ms
06-10 13:56:20.166: D/EXCEPTION(27328): Location Selection java.lang.NullPointerException
06-10 13:56:21.906: D/dalvikvm(260): GC_EXPLICIT freed 66 objects / 3040 bytes in 128ms

EDIT 2: //Network connection class

public class NetworkConnection extends Activity {
    /** Called when the activity is first created. */

    public boolean isNetworkConnAvail(Context context) {

        ConnectivityManager connMgr = (ConnectivityManager) 
            context.getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo networkInfo = connMgr.getActiveNetworkInfo();
        if (networkInfo != null)
            return networkInfo.isConnected();

        return false;
    }
}

//Print statment

06-10 14:10:40.015: D/AndroidRuntime(27731): >>>>>>>>>>>>>> AndroidRuntime START <<<<<<<<<<<<<<
06-10 14:10:40.015: D/AndroidRuntime(27731): CheckJNI is ON
06-10 14:10:40.145: D/AndroidRuntime(27731): --- registering native functions ---
06-10 14:10:40.535: D/dalvikvm(27670): GC_EXPLICIT freed 1408 objects / 74352 bytes in 898ms
06-10 14:10:40.645: D/AndroidRuntime(27731): Shutting down VM
06-10 14:10:40.645: D/dalvikvm(27731): Debugger has detached; object registry had 1 entries
06-10 14:10:40.665: I/AndroidRuntime(27731): NOTE: attach of thread 'Binder Thread #3' failed
06-10 14:10:41.045: D/AndroidRuntime(27739): >>>>>>>>>>>>>> AndroidRuntime START <<<<<<<<<<<<<<
06-10 14:10:41.045: D/AndroidRuntime(27739): CheckJNI is ON
06-10 14:10:41.166: D/AndroidRuntime(27739): --- registering native functions ---
06-10 14:10:41.655: I/ActivityManager(59): Starting activity: Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10000000 cmp=com.swiftdrink/.SplashScreen }
06-10 14:10:41.695: D/AndroidRuntime(27739): Shutting down VM
06-10 14:10:41.695: D/dalvikvm(27739): Debugger has detached; object registry had 1 entries
06-10 14:10:41.775: I/dalvikvm(27739): JNI: AttachCurrentThread (from ???.???)
06-10 14:10:41.775: I/AndroidRuntime(27739): NOTE: attach of thread 'Binder Thread #3' failed
06-10 14:10:42.465: I/ActivityManager(59): Displayed activity com.swiftdrink/.SplashScreen: 799 ms (total 799 ms)
06-10 14:10:42.845: I/ActivityManager(59): Starting activity: Intent { act=com.swiftdrink.SWIFTDRINKMAIN cmp=com.swiftdrink/.SwiftDrinkMain }
06-10 14:10:42.895: V/one(27670): locationSelection
06-10 14:10:43.186: I/ActivityManager(59): Displayed activity com.swiftdrink/.SwiftDrinkMain: 337 ms (total 337 ms)
06-10 14:10:45.185: D/EXCEPTION(27670): Location Selection java.lang.NullPointerException
06-10 14:10:45.185: W/System.err(27670): java.lang.NullPointerException
06-10 14:10:45.205: W/System.err(27670):    at android.content.ContextWrapper.getApplicationContext(ContextWrapper.java:100)
06-10 14:10:45.205: W/System.err(27670):    at com.swiftdrink.Location.locationSelection(Location.java:39)
06-10 14:10:45.205: W/System.err(27670):    at com.swiftdrink.Options$2.onClick(Options.java:73)
06-10 14:10:45.205: W/System.err(27670):    at android.view.View.performClick(View.java:2408)
06-10 14:10:45.205: W/System.err(27670):    at android.view.View$PerformClick.run(View.java:8816)
06-10 14:10:45.205: W/System.err(27670):    at android.os.Handler.handleCallback(Handler.java:587)
06-10 14:10:45.216: W/System.err(27670):    at android.os.Handler.dispatchMessage(Handler.java:92)
06-10 14:10:45.216: W/System.err(27670):    at android.os.Looper.loop(Looper.java:123)
06-10 14:10:45.216: W/System.err(27670):    at android.app.ActivityThread.main(ActivityThread.java:4627)
06-10 14:10:45.216: W/System.err(27670):    at java.lang.reflect.Method.invokeNative(Native Method)
06-10 14:10:45.216: W/System.err(27670):    at java.lang.reflect.Method.invoke(Method.java:521)
06-10 14:10:45.216: W/System.err(27670):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
06-10 14:10:45.216: W/System.err(27670):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
06-10 14:10:45.226: W/System.err(27670):    at dalvik.system.NativeStart.main(Native Method)
06-10 14:10:48.366: D/dalvikvm(114): GC_EXPLICIT freed 239 objects / 11320 bytes in 128ms

Upvotes: 0

Views: 1176

Answers (1)

Raghav Sood
Raghav Sood

Reputation: 82543

You create an instance of the Location class by using loc = new Location(); Now Location is a class extending Activity, and as you are not launching it like normal Activities (via Intents, for example), onCreate() is never called. Due to this, your getApplicationContext() will return null, as your Activity hasn't been instantiated as expected.

To fix this, you can add a constructor to the class like this:

//New Global Variable

Context context;

public Location (Context arg)
{
context = arg;
}

Also, you'll need to change the SharedPreferences initialization to use the context variable instead of getApplicationContext().

And then assign loc using:

loc = new Location(getApplicationContext());

This should solve at least your NullPointerException.

Your SocketException seems to be occurring because of an unsupported Address type, but from the code you've posted, you don't seem to be using any address at all.

Upvotes: 1

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