Static variable returns null when returning to the app

Question

I have two activitys the first one is LoginActivity where I have this five static variables:

public static Login loginTargetApp;
public static Gateway gateway;
public static Login loginGateway;
public static OfflineUser offlineUser;
public static boolean isLoggedIn;

In my second activity, MainViewActivity, when I try to acess this variables after android destroyed and reacreated my activity it returns null and the app crashes:

jsonTempDownload = new File(Constants.DEST_PATH_PARENT + File.separator
                    + LoginActivity.gateway.getUuidInstituicao() + Constants.JSON_TEMP_DOWNLOAD);

I'm trying to save variable states doing:

@Override
protected void onSaveInstanceState(Bundle saveInstanceState) {

    saveInstanceState.putParcelable("loginTargetApp", LoginActivity.loginTargetApp);
    saveInstanceState.putParcelable("gateway", LoginActivity.gateway);
    saveInstanceState.putParcelable("loginGateway", LoginActivity.loginGateway);
    saveInstanceState.putParcelable("offlineUser", LoginActivity.offlineUser);

    saveInstanceState.putBoolean("isLoggedIn", LoginActivity.isLoggedIn);

    super.onSaveInstanceState(saveInstanceState);
}

To recover my variable values I've tried two different ways, but they didn't work:

@Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {

    super.onRestoreInstanceState(savedInstanceState);

    LoginActivity.loginTargetApp = savedInstanceState.getParcelable("loginTargetApp");
    LoginActivity.gateway = savedInstanceState.getParcelable("gateway");
    LoginActivity.loginGateway = savedInstanceState.getParcelable("loginGateway");
    LoginActivity.offlineUser = savedInstanceState.getParcelable("offlineUser");

    LoginActivity.isLoggedIn = savedInstanceState.getBoolean("isLoggedIn");

}

and:

@Override
    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        Log.d(Constants.MAIN_VIEW_ACTIVITY, "----------------");
        Log.d(Constants.MAIN_VIEW_ACTIVITY, "Abrindo MainViewActivity...");
        Log.d(Constants.MAIN_VIEW_ACTIVITY, "----------------");

        if (savedInstanceState != null) {

            // Restore value of members from saved state

            LoginActivity.isLoggedIn = savedInstanceState.getBoolean("isLoggedIn");
            boolean isLoggedIn = savedInstanceState.getBoolean("isLoggedIn");
            Log.d(Constants.MAIN_VIEW_ACTIVITY, "VARIÁVEL NORMAL: " + isLoggedIn);
            Log.d(Constants.MAIN_VIEW_ACTIVITY, "VARIÁVEL ESTÁTICA: " + LoginActivity.isLoggedIn);

            LoginActivity.loginTargetApp = savedInstanceState.getParcelable("loginTargetApp");
            Login loginTargetApp = savedInstanceState.getParcelable("loginTargetApp");
            Log.d(Constants.MAIN_VIEW_ACTIVITY, "VARIÁVEL NORMAL: " + loginTargetApp.getEmailAndress());
            Log.d(Constants.MAIN_VIEW_ACTIVITY, "VARIÁVEL ESTÁTICA: " + LoginActivity.loginTargetApp.getEmailAndress());

            LoginActivity.gateway = savedInstanceState.getParcelable("gateway");
            LoginActivity.loginGateway = savedInstanceState.getParcelable("loginGateway");

            LoginActivity.offlineUser = savedInstanceState.getParcelable("offlineUser");
            OfflineUser offlineUser = savedInstanceState.getParcelable("offlineUser");
            Log.d(Constants.MAIN_VIEW_ACTIVITY, "VARIÁVEL NORMAL: " + offlineUser.getEmail());
            Log.d(Constants.MAIN_VIEW_ACTIVITY, "VARIÁVEL ESTÁTICA: " + LoginActivity.offlineUser.getEmail());

        } else {

            Log.d(Constants.MAIN_VIEW_ACTIVITY, "SAVED INSTANCE STATE IS NULL");
        }

In onCreate method my savedInstance is not null but when I try to show the values in Log.d, it's still crashing.

when activity is destroyed and recreated your static variables are re-initialized — Raghunandan
– Raghunandan, Commented Jun 20, 2013 at 14:50
but I'm saving it's states in saveInstanceState and reassigning in onRestoreInstanceState. — Victor Laerte
– Victor Laerte, Commented Jun 20, 2013 at 14:55

LuckyMe · Accepted Answer · 2013-06-20 15:26:29Z

1

Couple of points:

1- static is not final and therefore can be null, in other words, make sure you are setting those values to something.

2- super.onRestoreInstanceState(savedInstanceState); should be called at the start of protected void onRestoreInstanceState(Bundle savedInstanceState) not end of it.

Source (Look at the end of the page)

Let me know, cheers.

edited Jun 20, 2013 at 15:26

answered Jun 20, 2013 at 14:57

LuckyMe

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1 Comment

Victor Laerte Over a year ago

You were right, I was doing something wrong trying to get values that was never instantiated, Thanks bro

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