shared preferences with getter and setter

Question

I am using SharedPreferences to handle session. My getter method is returning null which is not supposed to.

Code :

public class SessionManager {
SharedPreferences pref;
SharedPreferences.Editor editor;
Context _context;
int PRIVATE_MODE = 0;
private static final String PREFER_NAME = "MyPref";
public static final String KEY_CURRENT_ID = "current_id";
public final String KEY_HANDLING_ID = "handling_id";
public final String KEY_HAS_PROFILE = "profile_exists";


public SessionManager(Context context) {
    this._context = context;
    pref = _context.getSharedPreferences(PREFER_NAME, PRIVATE_MODE);
    editor = pref.edit();
}

public void setCurrentId(int id) {
    editor.putInt(KEY_CURRENT_ID, id);
    editor.commit();
}

public int getCurrentId() {
    return pref.getInt(KEY_CURRENT_ID, 0);
}

public int getHandlingId() {
    return pref.getInt(KEY_HANDLING_ID, 0);
}

public void setHandlingId(int id) {
    editor.putInt(KEY_HANDLING_ID, id);
    editor.commit();
}


public boolean getHasProfile() {
    return pref.getBoolean(KEY_HAS_PROFILE, false);
}

public void setHasProfile() {
    boolean f;
    if(AppController.getInstance().getProfile()!=null){
        f=true;
    }else {
        f=false;
    }
    editor.putBoolean(KEY_HAS_PROFILE, f);
    editor.commit();
}

public void GenerateAndSetId(int profile_id) {
    int id=0;
    if (AppController.getInstance().getProfile() != null) {
        for (int i = 0; i < AppController.getInstance().getProfile().size() && (AppController.getInstance().getProfile().get(i).getId() == profile_id); i++) {
            id=i;
            break;
        }
    }
    setHandlingId(id);
}

}

when I use in Activity

 new SessionManager(getApplicationContext()).getHandlingId();

it returns NullPointerException. Even if I set

 new SessionManager(getApplicationContext()).setHandlingId(1);

then also getHandlingId() returns NullPointerException.

but if I define SharedPreferences in my Activity class it shows the stored id.

 SharedPreferences pref = getApplicationContext().getSharedPreferences("MyPref", 0);pref.edit().putInt("handling_id",1).commit();
        Log.d("Status new id " ,"  "+pref.getInt("handling_id",0));

which is 1.

I have googled a lot but unable to solve this issue.

Logcat:

E/AndroidRuntime: FATAL EXCEPTION: main java.lang.RuntimeException: Unable to start activity ComponentInfo{com.monitoryourweight.patriotic/com.monitoryourweight.patriotic.ManageProfileView}: java.lang.NullPointerException
 at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2247)
 at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2297)
 at android.app.ActivityThread.access$700(ActivityThread.java:152)
 at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1282)
 at android.os.Handler.dispatchMessage(Handler.java:99)
 at android.os.Looper.loop(Looper.java:137)
 at android.app.ActivityThread.main(ActivityThread.java:5328)
 at java.lang.reflect.Method.invokeNative(Native Method)
 at java.lang.reflect.Method.invoke(Method.java:511)
 at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1102)
 at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:869)
 at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
 at com.monitoryourweight.patriotic.ManageProfileView.setUpList(ManageProfileView.java:170)
 at com.monitoryourweight.patriotic.ManageProfileView.init(ManageProfileView.java:70)
 at com.monitoryourweight.patriotic.ManageProfileView.onCreate(ManageProfileView.java:65)
 at android.app.Activity.performCreate(Activity.java:5250)
 at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1097)
 at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2211)
 at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2297) 
 at android.app.ActivityThread.access$700(ActivityThread.java:152) 
 at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1282) 
 at android.os.Handler.dispatchMessage(Handler.java:99) 
 at android.os.Looper.loop(Looper.java:137) 
 at android.app.ActivityThread.main(ActivityThread.java:5328) 
 at java.lang.reflect.Method.invokeNative(Native Method) 
 at java.lang.reflect.Method.invoke(Method.java:511) 
 at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1102)     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:869) 
 at dalvik.system.NativeStart.main(Native Method)

ManageProfileView.java

public class ManageProfileView extends FragmentActivity implements View.OnClickListener, DialogListener {


private SeparatedListAdapter adapter;
private List<Map<String, ?>> profile, weight, option;
private ListView profile_listview;
private Button back_btn, save_btn;
private TextView list_caption;
private Profile userProfile;
private boolean[] status;
private boolean statusName = true;
private int type;
private SessionManager session;


@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.manage_profile);
    init();
//other code
}

private void init() {
    setUpList(getIntent().getExtras().getInt("type"));
    session = new SessionManager(ManageProfileView.this);
    //other code
}

private void setUpList(int type) {
    profile_listview = (ListView) findViewById(R.id.profile_listview);
    adapter = new SeparatedListAdapter(this);

    this.type = type;

    if (type == 2 && statusName) {
        SharedPreferences pref = getApplicationContext().getSharedPreferences("MonitorWeightPref", 0);
        pref.edit().putInt("handling_id", 1).commit();
        Log.d("Status new 2 ", "  " + pref.getInt("handling_id", 0));
        new SessionManager(getApplicationContext()).getHandlingId();
        session.setHandlingId(0);

        //ERROR IS HERE
        int x = session.getHandlingId();


        userProfile = AppController.getInstance().getProfile().get(x);

        final View footer = ((LayoutInflater) this.getSystemService(Context.LAYOUT_INFLATER_SERVICE)).inflate(R.layout.list_footer, null, false);
        footer.setOnClickListener(this);
        profile_listview.addFooterView(footer);
    } else {
        userProfile = new Profile();
    }

}

public static Map<String, ?> createItem(String paramString1, String paramString2) {
    HashMap localHashMap = new HashMap();
    localHashMap.put("title", paramString1);
    localHashMap.put("caption", paramString2);
    return localHashMap;
}

@Override
public void onClick(View v) {
//other code
}
}

`int` is a primitive data type, so the method is not returning NPE, rather the method you're calling inside `getHandlingId()` is throwing NPE. Most likely the `pref` is null. Please post the entire logcat — nstosic, Jan 08 '16 at 13:18
NullPointerException occurs in ManageProfileView.java in 170 line Could you add ManageProfileView.java file — Konrad Krakowiak, Jan 08 '16 at 13:28
Well, there you have where NPE is thrower: ManageProfileView.java, line 170. Look there. — Fustigador, Jan 08 '16 at 13:29
Possible duplicate of [What is a Null Pointer Exception, and how do I fix it?](http://stackoverflow.com/questions/218384/what-is-a-null-pointer-exception-and-how-do-i-fix-it) — Damian Kozlak, Jan 08 '16 at 13:33
Try ManageProfileView.this instead of getApplicationContext() — Fustigador, Jan 08 '16 at 13:42
Why are you doing new SessionManager(getApplicationContext()).getHandlingId(); if you have your session object? — Fustigador, Jan 08 '16 at 13:57

Damian Kozlak · Accepted Answer · 2016-01-08T13:58:41.140

1

UPDATED:

You execute method setUpList(), which uses session variable, while it is still not initialized.

Switch:

setUpList(getIntent().getExtras().getInt("type"));
session = new SessionManager(ManageProfileView.this);

to

session = new SessionManager(ManageProfileView.this);
setUpList(getIntent().getExtras().getInt("type"));

You have only declared session variable, without initialization, so on line

int x = session.getHandlingId();

you're getting NullPointerException because session is null.

To fix it, change:

new SessionManager(getApplicationContext()).getHandlingId();

to

session = new SessionManager(getApplicationContext());

edited Jan 08 '16 at 13:58

answered Jan 08 '16 at 13:46

Damian Kozlak

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Sorry for pasting the dummy code. Though My code his about 400 lines. so, i paste the flow only. i have already initialized it before. – Patriotic Jan 08 '16 at 13:52
@user3751576 Also like Fustigador said above, you should check line `new SessionManager(getApplicationContext()).getHandlingId(); ` in `setUpList()` method, because it should be removed – Damian Kozlak Jan 08 '16 at 14:13

shared preferences with getter and setter

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