NullPointer when get ActionBar

Question

I used the following code from this Q/A to change the background color of ActionBar:

public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    getWindow().requestFeature(Window.FEATURE_ACTION_BAR);
    ActionBar bar = getActionBar();
    bar.setBackgroundDrawable(new ColorDrawable(Color.parseColor("#000000")));
    setContentView(R.layout.activity_main);
}
//More codes here
}

I know that I should use getSupportActionBar() when using android.support.v7.app.ActionBarActivity. I don't use support v7. I am working in andoridx environment and I have imported the followings but I am not sure if these relating to the problem :

import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;

java.lang.NullPointerException: Attempt to invoke virtual method 'void android.app.ActionBar.setBackgroundDrawable(android.graphics.drawable.Drawable)' on a null object reference

You should call `getActionBar` after you've set the content view, not before. — Edric, Nov 09 '19 at 11:58
Did you move the line which sets the background drawable as well? — Edric, Nov 09 '19 at 12:10
Yes I moved both lines. I guess the problem is new syntax of andoridx.@Edric — Ali Sheikhpour, Nov 09 '19 at 12:19
It's probably because you should've extended `ActionBarActivity` instead of `Activity`. — Edric, Nov 09 '19 at 15:43
It seems that `ActionBarActivity` was deprecated and removed in v26 of the Support Library: https://stackoverflow.com/questions/29877692/why-was-actionbaractivity-deprecated — Edric, Nov 09 '19 at 15:51

score 0 · Answer 1 · answered Nov 09 '19 at 12:03

0

Use getSupportActionBar() instead of getActionBar()

after setContentView(R.layout.activity_main);

answered Nov 09 '19 at 12:03

Rahul Gaur

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I am not using support package – Ali Sheikhpour Nov 09 '19 at 12:09
use the line `getActionBar()` after `setContentView(R.layout.activity_main);` setContentView initiate Layout which will generate ActionBar – Rahul Gaur Nov 09 '19 at 12:10

score 0 · Accepted Answer · answered Nov 09 '19 at 12:54

I have solved the problem by setting up the environment as the following:

adding:

import static androidx.appcompat.app.AppCompatDelegate.FEATURE_SUPPORT_ACTION_BAR;

changing

extends Activity

to

extends AppCompatActivity

and shifting to support package by:

ActionBar bar = getSupportActionBar();

NullPointer when get ActionBar

2 Answers2