Why does this force close before the activity screen is drawn? (android)

Question

my app keeps force closing before it starts... eclipse returns no errors in my code and my xml is good. can anybody give me some insight?

package com.mhe.test.scan;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

public class main extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        Button myScanButton = (Button) findViewById(R.id.myScanButton);         
          myScanButton.setOnClickListener(new Button.OnClickListener() {
            public void onClick(View v) {
                Intent intent = new Intent("com.google.zxing.client.android.SCAN");
                intent.putExtra("SCAN_MODE", "PRODUCT_MODE");
                startActivityForResult(intent, 0);

               }
            });
    }


    EditText totalbox = (EditText) findViewById(R.id.totalbox);
        public void onActivityResult(int requestCode, int resultCode, Intent intent) {
            if (requestCode == 0) {
                if (resultCode == RESULT_OK) {
                    String contents = intent.getStringExtra("SCAN_RESULT");
                    // Handle successful scan
                    totalbox.setText(contents);
                } else if (resultCode == RESULT_CANCELED) {
                    // Handle cancel
                    totalbox.setText("@string/bummer");
                }



            }      
         }
    }

essentially it is supposed to call zxing Barcode Scanner to scan a barcode on a button click and return the result into an EditText field... i'm a total newbie at this...

Answer 1

A question. Bare with me Im fairly new at all this android coding so I might be leading you down a rabbit hole.

Are you testing on a phone with zxing on it? I don't know if it will cause the program to force close if it is not there already before button push.

Answer 2

The line:

EditText totalbox = (EditText) findViewById(R.id.totalbox);

Is not in the OnCreate method, so its trying to initialize the totalbox before the activity is created, probably causing the crash

Try this instead:

package com.mhe.test.scan;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

public class main extends Activity {
  /** Called when the activity is first created. */
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    Button myScanButton = (Button) findViewById(R.id.myScanButton); 
    // set the totalbox in the onCreate
    totalbox = (EditText) findViewById(R.id.totalbox);        
    myScanButton.setOnClickListener(new Button.OnClickListener() {
      public void onClick(View v) {
        Intent intent = new Intent("com.google.zxing.client.android.SCAN");
        intent.putExtra("SCAN_MODE", "PRODUCT_MODE");
        startActivityForResult(intent, 0);
      }
    });
  }

  public void onActivityResult(int requestCode, int resultCode, Intent intent) {
    if (requestCode == 0) {
      if (resultCode == RESULT_OK) {
        String contents = intent.getStringExtra("SCAN_RESULT");
        // Handle successful scan
        // check that it exists, just in case
        if ( totalbox != null )
          totalbox.setText(contents);
      } else if (resultCode == RESULT_CANCELED) {
        // Handle cancel
        // check that it exists, just in case
        if ( totalbox != null )
          totalbox.setText("@string/bummer");
      }
    }      
  }

  private EditText totalbox;
}