findViewById returns null after calling setContentView

Question

I try to reference a TextView in my java file through findViewById(int), but this seems to return null even after calling setContentView(int) with the correct layout file.

Help.xml

<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" > <TextView android:id="@+id/tvBoxHelp" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/help" android:layout_gravity="center" android:textSize="20sp" /> </LinearLayout>

Help.java

 public class Help extends Activity { private TextView tv; @Override protected void onCreate(Bundle savedInstanceState) { // TODO Auto-generated method stub setContentView(R.layout.help); tv = (TextView) findViewById(R.id.tvBoxHelp); tv.setText("text"); super.onCreate(savedInstanceState); } }

Thanks in advance.

super.onCreate(savedInstanceState) should be called directly after onCreate() — mihirjoshi
– mihirjoshi, Commented Dec 25, 2012 at 7:42

OneCricketeer · Accepted Answer · 2017-06-12 21:59:21Z

4

Your super.onCreate(savedInstanceState); position is causing problem.

Replace your Help.java with this

public class Help extends Activity { private TextView tv; @Override protected void onCreate(Bundle savedInstanceState) { // TODO Auto-generated method stub super.onCreate(savedInstanceState); setContentView(R.layout.help); tv = (TextView) findViewById(R.id.tvBoxHelp); tv.setText("text"); } }

edited Jun 12, 2017 at 21:59

OneCricketeer

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answered Dec 25, 2012 at 7:39

Rahul

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3 Comments

Tanuj Nayak Over a year ago

Actually that doesn't seem to fix it.

Tanuj Nayak Over a year ago

During debug the textview's id seems to be "-1".

Rahul Over a year ago

I checked your code and it works fine on my computer. Try to clean your code from project tab on eclipse. In your TextView what you want to show? You getting text on TextView or not ?

Paresh Mayani · Accepted Answer · 2012-12-25 07:41:01Z

1

call super method (super.onCreate(savedInstanceState);) before setting your content view

answered Dec 25, 2012 at 7:41

Paresh Mayani

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5 Comments

Tanuj Nayak Over a year ago

Thanks I should've seen that.

Muhammad Babar Over a year ago

But im changing my contentView after the onCreate()? Getting null with findViewById() any idea?

Paresh Mayani Over a year ago

@MuhammadBabar that shouldn't be the case. I can't tell you exactly where is the issue without checking your code.

Muhammad Babar Over a year ago

@PareshMayani thanks Paresh! In my case i was changing the content view after some time in activity i.e in onCreate() setContentView() was called before and successfully setted, null thing was happening, but now i solved it by doing a trick.

Paresh Mayani Over a year ago

@MuhammadBabar Keep calm and enjoy programming :-)

Gauraw Yadav · Accepted Answer · 2012-12-25 07:48:42Z

 public class Help extends Activity { private TextView tv; @Override protected void onCreate(Bundle savedInstanceState) { // TODO Auto-generated method stub // setContentView(R.layout.help); tv = (TextView) findViewById(R.id.tvBoxHelp); tv.setText("text"); //This should be called first super.onCreate(savedInstanceState); super.onCreate(savedInstanceState); } }

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