Array of android buttons

Question

Can't work out a way to make an array of buttons in android.

This is the code I have tried but I'm getting a java.lang.NullPointerException.

    private Button[] button = {(Button) findViewById(R.id.cGuess1),
        (Button) findViewById(R.id.cGuess2),(Button)
        findViewById(R.id.cGuess3),(Button) findViewById(R.id.cGuess4)};

Is this even possible?

EDIT:

Sorry everyone. Just realised my mistake!

I was trying to declare the array for my whole class and trying to get the views from the ids before onCreate so there was no setContentView(R.layout.game);

Sorry.

yes, possible . what error or unexpected result you are facing ??? share detailed code — Shailendra Singh Rajawat
– Shailendra Singh Rajawat, Commented Jan 9, 2012 at 12:55
Well all I'm getting is the "java.lang.NullPointerException" on the line shown. Not even got far enough to even work with the array. — A_Porcupine
– A_Porcupine, Commented Jan 9, 2012 at 12:56
please post the full exception from your LogCat, it could be that your view has not been inflated — Guillaume
– Guillaume, Commented Jan 9, 2012 at 12:57
this means one more more button is missing among cGuess1,2,3 and 4 . cant say more before have a look of xml and java — Shailendra Singh Rajawat
– Shailendra Singh Rajawat, Commented Jan 9, 2012 at 13:05
Well that's great you have realized your mistake. But accept or upvote the comments and answers that helped you. — Usama Sarwar
– Usama Sarwar, Commented Jan 9, 2012 at 13:29

Josh · Accepted Answer · 2012-01-09 14:02:04Z

2

Since no one else posted actual code for a solution, here's a working snippet.

Button[] myButtons = null;

@Override
public void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);

    setContentView(R.layout.main);

    myButtons = new Button[]
    {
            (Button)findViewById(R.id.button1),
            (Button)findViewById(R.id.button2),
            (Button)findViewById(R.id.button3),
    };
}

answered Jan 9, 2012 at 14:02

Josh

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Comments

jeet · Accepted Answer · 2012-01-09 13:04:56Z

1

Just a guess as full code is not available here, have you called setContentView() before creating array.

answered Jan 9, 2012 at 13:04

jeet

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Comments

Deepak · Accepted Answer · 2012-01-09 12:57:18Z

1

Could you try

final Button[] button = {(Button) findViewById(R.id.cGuess1), 
    (Button) findViewById(R.id.cGuess2),(Button) 
    findViewById(R.id.cGuess3),(Button) findViewById(R.id.cGuess4)};

answered Jan 9, 2012 at 12:57

Deepak

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Comments

Usama Sarwar · Accepted Answer · 2012-01-09 13:01:37Z

1

One of your buttons may be null. And putting a private keyword does not allow me to create the array. Also see that Firstly you are setting the cententView for your activity and then accessing these buttons.

answered Jan 9, 2012 at 13:01

Usama Sarwar

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Comments

enb081 · Accepted Answer · 2015-04-23 07:35:21Z

0

public class main2 extends Activity{
    final int[] button = {R.id.button1,R.id.button2,R.id.button3,R.id.button4,R.id.button5,
            R.id.button6,R.id.button7,R.id.button8,R.id.button9,R.id.button10};
    Button[] bt = new Button[button.length];
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.sign);
        for(int i=0;i<button.length;i++){
            final Context context = this;
            final int b = i;
            bt[b]= (Button) findViewById(button[b]);
            Typeface font = Typeface.createFromAsset(getAssets(), "Angkor.ttf");
            bt[b].setTypeface(font);
            bt[b].setOnClickListener(new OnClickListener() {

                @Override
                public void onClick(View v) {
                    // TODO Auto-generated method stub
                    Intent myIntent = new Intent(context,r1.class);
                    startActivity(myIntent);
                }
            });
        }
    }
}

edited Apr 23, 2015 at 7:35

enb081

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answered Apr 23, 2015 at 7:19

Phearum Chheang

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2 Comments

Wai Ha Lee Over a year ago

Hi @PhearumChheang, could you explain your answer please? Code without comment is less helpful than well commented code that others can learn from. Thank you.

Phearum Chheang Over a year ago

Sorry about some mistakes. This code is for have many buttons and want to loop it for use only one purpose. For example, you want to start new activity by click on button whatever you want.

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