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How To Save Users' Last Read Page Number

I am building an android app which displaying a specific pdf through https://github.com/barteksc/AndroidPdfViewer with lots of pages, and now i was just implementing a method to re-open the pdf from the last opened page of the user.

I am using SharedPreferences to store the current page, and then after reloading the app, the app will re-open the pdf where user left.

Here is my Shared Preferences method to store and retrieve the data

private void storepreferences () {
    PDFView pdfView = findViewById(R.id.pdfView);
    savedpage=pdfView.getCurrentPage();
    SharedPreferences pref = getApplicationContext().getSharedPreferences("MyPref", MODE_PRIVATE);
    SharedPreferences.Editor editor = pref.edit();
    editor.putInt("key_name2", savedpage);
    editor.apply();
}
private void getpreferences () {
    SharedPreferences pref = getApplicationContext().getSharedPreferences("MyPref", MODE_PRIVATE);
    pageNumber = pref.getInt("key_name2", 0);             // getting Integer
}

And then i am using onCreate

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    storepreferences();
    getpreferences();

Also for a test i am displaying the

TextView txt = findViewById(R.id.textView2);
txt.setText(String.valueOf(pageNumber));

But Still i am getting the default value, What i am doing wrong can anyone tell me?

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Answer

Finally I achieved this, I was using (storepreferences) on OnCreate before but now On I am using at BackPressed

@Override
public void onBackPressed() {
    DrawerLayout drawer = findViewById(R.id.drawer_layout);
    if (drawer.isDrawerOpen(GravityCompat.START)) {
        drawer.closeDrawer(GravityCompat.START);
    } else {
        storepreferences();
        super.onBackPressed();
    }
}

After that I am retrieving saved data on OnCreate

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        getpreferences();
}

I am using the above technique because I thought It is actually not storing my data, because When i use Toast to display the current Page, it was showing exactly the page number where user is

public void pagestorebutton (){
        PDFView pdfView = findViewById(R.id.pdfView);
        savedpage = pdfView.getCurrentPage();
        Toast myToast = Toast.makeText(this,(String.valueOf(savedpage) ), Toast.LENGTH_SHORT);
        myToast.show();
        storepreferences();
    }

And in onCreate i am using above function after clicking a Floating Button

FloatingActionButton fab4 = findViewById(R.id.fab4);
        fab4.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                pagestorebutton();
            }
        });

Is my Method is achieving my Goal through right path, or is there something more to do??

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source: stackoverflow.com
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