android - Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference [duplicate]

Question

I'm trying to set the text of the navigation drawer activity from the fetched data on my database, but when i try to do so, it throws the following error

Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference

Am I missing something or did I do something wrong in my code?

public void fetchDb(){
    String email = getIntent().getExtras().getString("EMAIL");

    TextView txtName = findViewById(R.id.nameText);
    TextView txtEmail = findViewById(R.id.emailText);
    String name, ema;

    DatabaseHelper dbh = new DatabaseHelper(this);

    newDb = dbh.getReadableDatabase();
    Cursor c = newDb.rawQuery("SELECT * FROM user WHERE user_email = \'" + email+"\'", null);
    if (c.moveToFirst()){
        do {
            name = c.getString(1);
            ema = c.getString(2);

            txtName.setText(name);
            txtEmail.setText(ema);

        } while(c.moveToNext());
    }
    c.close();
    newDb.close();
}

my text view names are correct, and are in the nav_header_main_menu.xml layout. — Ivan Cristobal
– Ivan Cristobal, Commented Apr 1, 2018 at 7:07
@IvanAldwinA.Cristobal Null pointer occurs if you access any method/variable of a class without initializing it ....... — Vikas singh
– Vikas singh, Commented Apr 1, 2018 at 7:18

sachinmaharjan182 · Accepted Answer · 2018-04-01 07:24:10Z

48

Null pointer try to say that the textview is null. That can happen beacause the findviewbyid is not matching with the right one on your xml. Be sure your id matches on your xml and java file

answered Apr 1, 2018 at 7:24

sachinmaharjan182

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2 Comments

Ivan Cristobal Over a year ago

The textviews are located on nav_header_main_menu.xml, not on activity_main_menu.xml, is it possible to edit the nav_header_main_menu text views on the MainMenu class?

sachinmaharjan182 Over a year ago

you need to find it on the view of nav_header. First create view for header and find it. NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view); navigationView.setNavigationItemSelectedListener(this); View header= navigationView.getHeaderView(0); text= header.findViewById(R.id.text);

Mihir Joshi · Accepted Answer · 2018-04-01 07:10:31Z

6

Possibly there are two situation.. If u are using older version of Android studio then u should use this TextView txtName = (TextView)findViewById(R.id.nameText);

Another possibility is that may be the layout is different where the textview is declared.

answered Apr 1, 2018 at 7:10

Mihir Joshi

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3 Comments

Ivan Cristobal Over a year ago

i am not using an older version, but i think it is the different layout. since the textviews i am declaring are in the nav_header_main_menu.xml file. not in the activity_main_menu.xml

Mihir Joshi Over a year ago

Yeah..then u have to pass the navheader context to findviewbyid..

NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view); View hView = navigationView.getHeaderView(0); TextView nav_user = (TextView)hView.findViewById(R.id.nav_name);

SpiritCrusher Over a year ago

Do not make assumptions as answer . First read the question .

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