CODEWITHSUNDEEP
android
mysterious
mysterious

Reputation: 1478

Change textView text in onCreate function

Can anyone tell me why am i getting error message java.lang.NullPointerException in following code??

package firstApp.hangman;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.widget.TextView;

public class HangmenActivity extends Activity 
{
    private String word_to_guess;

    @Override
    public void onCreate(Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);
        this.set_random_word(); 
        TextView wordToGuess = (TextView) findViewById(R.id.word_to_guess);
        try
        {
            wordToGuess.setText(this.word_to_guess);
        }
        catch(Exception  e)
        {
            AlertDialog alertDialog = new AlertDialog.Builder(this).create();
            alertDialog.setTitle("error");
            alertDialog.setMessage(e.toString());
            alertDialog.setButton("OK", new DialogInterface.OnClickListener() {
               public void onClick(DialogInterface dialog, int which) {
                  // here you can add functions
               }
            });
            alertDialog.setIcon(R.drawable.icon);
            alertDialog.show();
        }

        setContentView(R.layout.main);
    }

    private void set_random_word()
    {
        this.word_to_guess = "abcdef";
    }    

}

Upvotes: 0

Views: 5858

Answers (1)

user717572
user717572

Reputation: 3652

You should put define your contentView before accessing a child of it, in your case a textview. The contentView hasn't been initialized so findViewbyId returns Null. 

  @Override
public void onCreate(Bundle savedInstanceState) 
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main); //Initialize the view
    this.set_random_word(); 
    TextView wordToGuess = (TextView) findViewById(R.id.word_to_guess);
    try
    {
        wordToGuess.setText(this.word_to_guess);
    }
    catch(Exception  e)
    {
        AlertDialog alertDialog = new AlertDialog.Builder(this).create();
        alertDialog.setTitle("error");
        alertDialog.setMessage(e.toString());
        alertDialog.setButton("OK", new DialogInterface.OnClickListener() {
           public void onClick(DialogInterface dialog, int which) {
              // here you can add functions
           }
        });
        alertDialog.setIcon(R.drawable.icon);
        alertDialog.show();
    }
}

Also, provide more information on the problem, i.e. by showing on which line the problem is. Learn using DDMS (google it) and don't post your code and ask us to solve it.

Upvotes: 2

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