Unable to get saved SharedPreferences value in a class inside statice method

Question

In my project I want to share my referral code with app link.I already save referral code in SharedPreferences but I am unable to set that message in a separate class.

public static SharedPreferences sharedPreferences;

public static void shareMyApp(Context context) {

    String link = "https://play.google.com/store/apps/details?id="+context.getPackageName()+"Signup with my referral code.My Code is "+sharedPreferences.getString("member_id",null);

    Intent sharingIntent = new Intent(Intent.ACTION_SEND);
    sharingIntent.setType("text/*");
    sharingIntent.putExtra(Intent.EXTRA_TEXT, link);
    context.startActivity(Intent.createChooser(sharingIntent, "Share Via"));
}

This method is present inside a java class.When this method called an error appear.

java.lang.NullPointerException: Attempt to invoke interface method 'java.lang.String android.content.SharedPreferences.getString(java.lang.String, java.lang.String)' on a null object reference

How Can I print that code with app link?

You don't initialize sharedPreferences, hence why it is null. https://developer.android.com/training/data-storage/shared-preferences#java — EDToaster, Jun 06 '19 at 18:37

score 1 · Answer 1 · answered Jun 06 '19 at 18:36

1

Did you initialized sharedPreferences?

something like

sharedPreferences = getSharedPreferences("", Context.MODE_PRIVATE);

answered Jun 06 '19 at 18:36

Djaf

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CommonsWare · Answer 2 · 2019-06-06T19:21:20.340

1

public static void shareMyApp(Context context) {
    SharedPreferences sharedPreferences = context.getSharedPreferences(PREF_NAME, Context.MODE_PRIVATE);
    String link = "https://play.google.com/store/apps/details?id="+context.getPackageName()+"Signup with my referral code.My Code is "+sharedPreferences.getString("member_id",null);

    Intent sharingIntent = new Intent(Intent.ACTION_SEND);
    sharingIntent.setType("text/plain");
    sharingIntent.putExtra(Intent.EXTRA_TEXT, link);
    context.startActivity(Intent.createChooser(sharingIntent, "Share Via"));
}

Here, I:

Move sharedPreferences to a local variable
Initialize it, using the approach you outlined in the comments (you will need to add a static import for PREF_NAME or otherwise fix that bit up to refer to your existing PREF_NAME constant)
Use text/plain instead of text/* (you are sending the content, so you specify what the MIME type is)

edited Jun 06 '19 at 19:21

answered Jun 06 '19 at 18:38

CommonsWare

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But get referral code as null – Arpan Sarkar Jun 06 '19 at 18:55
@ArpanSarkar: You may be using a different `SharedPreferences`, then. Somewhere else in your app, you are working with `SharedPreferences` to save data. There are lots of `SharedPreferences` objects, and I do not know what one you used. In my sample, I showed one common approach for getting a `SharedPreferences` object. As I wrote, you should replace `PreferenceManager.getDefaultSharedPreferences(context)` from my example with whatever code you are presently using to get your `SharedPreferences` object. – CommonsWare Jun 06 '19 at 18:57
what SharedPreferences is suitable for your answer – Arpan Sarkar Jun 06 '19 at 19:03
@ArpanSarkar: You are welcome to save your data to `PreferenceManager.getDefaultSharedPreferences(context)`. That is a common `SharedPreferences` for the entire app, and it is what preference screens use. – CommonsWare Jun 06 '19 at 19:04
public MyAppPrefsManager(Context context) { sharedPreferences = context.getSharedPreferences(PREF_NAME, PRIVATE_MODE); prefsEditor = sharedPreferences.edit(); } – Arpan Sarkar Jun 06 '19 at 19:07
I use this SharedPreferences custom – Arpan Sarkar Jun 06 '19 at 19:08
@ArpanSarkar: That is fine. Replace `PreferenceManager.getDefaultSharedPreferences(context)` in my sample with `context.getSharedPreferences(PREF_NAME, PRIVATE_MODE)` (though you will need to ensure that you can get access to the `PREF_NAME` constant). – CommonsWare Jun 06 '19 at 19:13
please edit your answer in code. – Arpan Sarkar Jun 06 '19 at 19:16
also get same result.get referral code as null – Arpan Sarkar Jun 06 '19 at 19:24
@ArpanSarkar: Then I have no means of helping you further. As I have stated repeatedly, you need to use the same code for reading the `SharedPreferences` as you do for writing the `SharedPreferences`. You will need to do that yourself. – CommonsWare Jun 06 '19 at 19:26
thanks for your response – Arpan Sarkar Jun 06 '19 at 19:34

Unable to get saved SharedPreferences value in a class inside statice method

2 Answers2