How to fix getActionBar method may produce java.lang.NullPointerException

Question

I am using a toolbar as my actionbar in an activity. I am trying to add the method getActionBar().setDisplayHomeAsUpEnabled(true); to the Activity.java file fo

Answer 1

Alternatively you could assert actionbar to not null.Add the assertion before calling your actionbar as follows

assert getSupportActionBar() != null;

Final snippet would therefore look as follows:

    setSupportActionBar((Toolbar) findViewById(R.id.toolbar));
    assert getSupportActionBar() != null;
    getSupportActionBar().setDisplayHomeAsUpEnabled(true);

Answer 2

  if(getSupportActionBar() != null){
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
    }
    OR

Replace the MainActivity extends AppCompatActivity to public class MainActivity extends AppCompatActivity

Answer 3

 if(actionBar != null) {
  actionBar.setHomeButtonEnabled(true);
  actionBar.setBackgroundDrawable(ContextCompat.getDrawable(mContext,
                                  R.drawable.action_bar_gradient));
 }

Answer 4

add assert getSupportActionBar() != null; before getSupportActionBar().setDisplayHomeAsUpEnabled(true);

Answer 5

Try this :

setSupportActionBar (toolbar);
if(getSupportActionBar () != null) {
assert getSupportActionBar () != null;
getSupportActionBar ().setDisplayHomeUpEnabled(true);
}

Note that setSupportActionBar(toolbar) should be before getSupportActionBar().

Answer 6

just check getSupportActionBar not equal to null

    setSupportActionBar(toolbar);

    if(getSupportActionBar() != null) {
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        getSupportActionBar().setTitle("Daily Shopping List");
    }