Android Programmatically setting button text

Question

Does anybody know how to programmatically set the text of a button?

thing is i'm not calling this from the main layout(setContentView) i'm calling it in a view thats inflated after an asynctask heres what i have tried but this is giving a null pointer exception on the 2nd line

Button mButton=(Button)findViewById(R.id.contact);
        mButton.setText("number");

heres my layout where i am calling the button

   <Button
       android:id="@+id/contact"
       android:layout_width="wrap_content"
       android:layout_height="wrap_content"
       android:layout_below="@+id/address"
       android:layout_toLeftOf="@+id/badge"
       android:background="@drawable/ic_btn_call"
       android:textSize="10dp"
       android:textStyle="bold"
       android:textColor="@color/white"/>

here my view i'm inflating

ClubInfo = LayoutInflater.from(getBaseContext()).inflate(R.layout.clubinfocell,
                null);

        TextView TeamNameText = (TextView) ClubInfo.findViewById(R.id.TeamName);
        TeamNameText.setText(teamName);

        TextView AddressText = (TextView) ClubInfo.findViewById(R.id.address);
        AddressText.setText(address1);



        Button mButton=(Button)ClubInfo.findViewById(R.id.contact);
        mButton.setText(telephone);

It gives NPE because mButton is null on first line. And that's is because findViewById didn't find a R.id.contact you provided to it. — Andrey Ermakov
– Andrey Ermakov, Commented Jun 22, 2012 at 11:02
Does textViews work correctly? If so, what is the difference between your TextViews and your Button in code/xml? — Arie
– Arie, Commented Jun 22, 2012 at 12:00

Tim Biegeleisen · Accepted Answer · 2017-04-26 15:07:19Z

33

Then use your view's object to initialize it:

Button mButton = (Button)your_view_object.findViewById(R.id.contact);
mButton.setText("number");

When you try to identify a view other than your Activity's layout, you have to pass the reference of that view like this. If not Android will keep looking for this element from the layout which you provided in the setContentView().

For example, consider you have inflated a view like this:

View View = mInflater.inflate(R.layout.gridelement, null);

Then use this View's object for the Button present in that inflated layout:

  Button mButton = (Button)View.findViewById(R.id.contact);

edited Apr 26, 2017 at 15:07

Tim Biegeleisen

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answered Jun 22, 2012 at 11:14

Andro Selva

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2 Comments

Luke Batley Over a year ago

i have edited my code to show my view i'm still getting null pointer exception

Andro Selva Over a year ago

Try surrounding this, with null check, if(mButton!=null) { mButton.setText(telephone);}

ρяσѕρєя K · Accepted Answer · 2012-06-22 11:04:31Z

2

change your code as:

@Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);//set layout here in which u have add contact in xml
        Button mButton=(Button)findViewById(R.id.contact);
        mButton.setText("number");

EDIT: Your \res\layout\main.xml look like as:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >
<Button
       android:id="@+id/contact"
       android:layout_width="wrap_content"
       android:layout_height="wrap_content"
       android:layout_below="@+id/address"
       android:layout_toLeftOf="@+id/badge"
       android:background="@drawable/ic_btn_call"
       android:textSize="10dp"
       android:textStyle="bold"
       android:textColor="@color/white"/>
</LinearLayout>

answered Jun 22, 2012 at 11:04

ρяσѕρєя K

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3 Comments

Luke Batley Over a year ago

problem is its not been loaded from the content view its a button within a inflated view that i have inflated after an Asynctask

ρяσѕρєя K Over a year ago

@LukeBatley : as your question u are getting all right answers.if problem is not solved then post more code and full explain of problem

ρяσѕρєя K Over a year ago

@LukeBatley : use

LayoutInflater inflater = (LayoutInflater)context.getSystemService(LAYOUT_INFLATER_SERVICE);   View ClubInfo=inflater.inflate(R.layout.clubinfocell, null);

instead of ClubInfo = LayoutInflater.from(getBaseContext()).inflate(R.layout.clubinfocell, null);

Samir Mangroliya · Accepted Answer · 2012-06-22 11:01:39Z

1

your mButton is null.so NPE.are you refrenced xml resources after setContentView

onCreate(){
...
setContentView(R.layout.yourlayout);

Button mButton=(Button)findViewById(R.id.contact);
mButton.setText("number");

}

answered Jun 22, 2012 at 11:01

Samir Mangroliya

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Comments

Freni · Accepted Answer · 2012-06-22 11:04:49Z

0

check R.java files import statement

are you sure that you have import it of the project you use .. and just format your layout (.xml ) file save it and again type the same statement

answered Jun 22, 2012 at 11:04

Freni

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