Null Object Reference on setOnClickListner Method

Question

Error:

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.kritisharan.tictactoe/com.example.kritisharan.tictactoe.starter_activity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.design.widget.FloatingActionButton.setOnClickListener(android.view.View$OnClickListener)' on a null object reference

Code in MainActivity:

public class MainActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.content_main);

    FloatingActionButton reset = (FloatingActionButton) findViewById(R.id.reset);

    reset.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            startActivity(new Intent(MainActivity.this, MainActivity.class));
        }
    });
}

XML Code in activity_main.xml

<include layout="@layout/content_main"/>

<android.support.design.widget.FloatingActionButton
    android:id="@+id/reset"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="bottom|end"
    android:layout_margin="10sp"
    android:src="@android:drawable/ic_menu_revert"/>

Don't know why it is considering a null reference. Searched all the solutions but couldn't find anything that works. Please help.

Show content_main.xml that you're inflating, not activity_main.xml. — Doug Stevenson, Mar 05 '16 at 09:32
startActivity(new Intent(MainActivity.this, MainActivity.class)); both in main activity check it — sasikumar, Mar 05 '16 at 09:33
You don't understand. In the onCreate you show, it's inflating content_main.xml. But in your description after that, you say you are showing activity_main.xml. That's not the same thing. — Doug Stevenson, Mar 05 '16 at 09:36
@Doug I am just using tools in the content_main.xml this way: — Kriti Sharan, Mar 05 '16 at 09:38
@Doug Thanks a tonne, I can't believe I made such a stupid error. — Kriti Sharan, Mar 05 '16 at 09:46

score 2 · Answer 1 · answered Mar 05 '16 at 09:35

2

Change this line of code:

setContentView(R.layout.content_main);

to: setContentView(R.layout.activity_main);

answered Mar 05 '16 at 09:35

Android Geek

7,328
2
17
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score 1 · Answer 2 · answered Mar 05 '16 at 09:36

1

Change your OnCreate() method with this one.

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

.......

}

Try this.

answered Mar 05 '16 at 09:36

HassanUsman

1,485
1
17
34

score 1 · Accepted Answer · answered Mar 05 '16 at 09:41

1

The content_main.xml you're inflating does not contain a view with id reset as you're trying to find in onCreate(). Perhaps you are inflating the wrong XML layout. It looks like you want activity_main.xml instead.

answered Mar 05 '16 at 09:41

Doug Stevenson

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Null Object Reference on setOnClickListner Method

3 Answers3