Pass value from CustomDialog to the main Activity
<pre><code>public class CustomDialog extends Dialog {

    public  int result = -1;    

    public CustomDialog(Context context, int theme) {
        super(context, theme);
        RadioGroup radioGroup = (RadioGroup) findViewById(R.id.rdbGp1);
        radioGroup.setOnCheckedChangeListener(new OnCheckedChangeListener() 
        {

            public void onCheckedChanged(RadioGroup arg0, int arg1) 
            {
                result = arg1;
                Log.i("Dialog", "Result="+result);
                cancel();
            }
        });
    }

    public CustomDialog(Context context) {
        super(context);

    }

    /**
     * Helper class for creating a custom dialog
     */
    public static class Builder {

        private Context context;
        private String title;
        private String message;
        private String positiveButtonText;
        private String negativeButtonText;
        private View contentView;

        private DialogInterface.OnClickListener 
                        positiveButtonClickListener,
                        negativeButtonClickListener;

        public Builder(Context context) {
            this.context = context;
        }

        /**
         * Set the Dialog message from String
         * @param title
         * @return
         */
        public Builder setMessage(String message) {
            this.message = message;
            return this;
        }

        /**
         * Set the Dialog message from resource
         * @param title
         * @return
         */
        public Builder setMessage(int message) {
            this.message = (String) context.getText(message);
            return this;
        }

        /**
         * Set the Dialog title from resource
         * @param title
         * @return
         */
        public Builder setTitle(int title) {
            this.title = (String) context.getText(title);
            return this;
        }

        /**
         * Set the Dialog title from String
         * @param title
         * @return
         */
        public Builder setTitle(String title) {
            this.title = title;
            return this;
        }

        /**
         * Set a custom content view for the Dialog.
         * If a message is set, the contentView is not
         * added to the Dialog...
         * @param v
         * @return
         */
        public Builder setContentView(View v) {
            this.contentView = v;
            return this;
        }

        /**
         * Set the positive button resource and it's listener
         * @param positiveButtonText
         * @param listener
         * @return
         */
        public Builder setPositiveButton(int positiveButtonText,
                DialogInterface.OnClickListener listener) {
            this.positiveButtonText = (String) context
                    .getText(positiveButtonText);
            this.positiveButtonClickListener = listener;
            return this;
        }

        /**
         * Set the positive button text and it's listener
         * @param positiveButtonText
         * @param listener
         * @return
         */
        public Builder setPositiveButton(String positiveButtonText,
                DialogInterface.OnClickListener listener) {
            this.positiveButtonText = positiveButtonText;
            this.positiveButtonClickListener = listener;
            return this;
        }

        /**
         * Set the negative button resource and it's listener
         * @param negativeButtonText
         * @param listener
         * @return
         */
        public Builder setNegativeButton(int negativeButtonText,
                DialogInterface.OnClickListener listener) {
            this.negativeButtonText = (String) context
                    .getText(negativeButtonText);
            this.negativeButtonClickListener = listener;
            return this;
        }

        /**
         * Set the negative button text and it's listener
         * @param negativeButtonText
         * @param listener
         * @return
         */
        public Builder setNegativeButton(String negativeButtonText,
                DialogInterface.OnClickListener listener) {
            this.negativeButtonText = negativeButtonText;
            this.negativeButtonClickListener = listener;
            return this;
        }

        /**
         * Create the custom dialog
         */
        public CustomDialog create() {
            LayoutInflater inflater = (LayoutInflater) context
                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            // instantiate the dialog with the custom Theme
            final CustomDialog dialog = new CustomDialog(context, 
                    R.style.Dialog);
            dialog.setOnCancelListener(new OnCancelListener() 
        {
        public void onCancel(DialogInterface arg0) 
        {
            Log.i("FooDialog", "Result="+dialog.result);
        }
        });
            View layout = inflater.inflate(R.layout.credits, null);
            dialog.addContentView(layout, new LayoutParams(
                    LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT));
            // set the dialog title
            ((TextView) layout.findViewById(R.id.title)).setText(title);
            // set the confirm button
            if (positiveButtonText != null) {
                ((Button) layout.findViewById(R.id.positiveButton))
                        .setText(positiveButtonText);
                if (positiveButtonClickListener != null) {
                    ((Button) layout.findViewById(R.id.positiveButton))
                            .setOnClickListener(new View.OnClickListener() {
                                public void onClick(View v) {
                                    positiveButtonClickListener.onClick(
                                            dialog, 
                                            DialogInterface.BUTTON_POSITIVE);
                                }
                            });
                }
            } else {
                // if no confirm button just set the visibility to GONE
                layout.findViewById(R.id.positiveButton).setVisibility(
                        View.GONE);
            }
            // set the cancel button
            if (negativeButtonText != null) {
                ((Button) layout.findViewById(R.id.negativeButton))
                        .setText(negativeButtonText);
                if (negativeButtonClickListener != null) {
                    ((Button) layout.findViewById(R.id.negativeButton))
                            .setOnClickListener(new View.OnClickListener() {
                                public void onClick(View v) {
                                    negativeButtonClickListener.onClick(
                                            dialog, 
                                            DialogInterface.BUTTON_NEGATIVE);
                                }
                            });
                }
            } else {
                // if no confirm button just set the visibility to GONE
                layout.findViewById(R.id.negativeButton).setVisibility(
                        View.GONE);
            }
            // set the content message
            if (contentView != null) {
                // if no message set
                // add the contentView to the dialog body
                ((LinearLayout) layout.findViewById(R.id.content))
                        .removeAllViews();
                ((LinearLayout) layout.findViewById(R.id.content))
                        .addView(contentView, 
                                new LayoutParams(
                                        LayoutParams.WRAP_CONTENT, 
                                        LayoutParams.WRAP_CONTENT));
            }
            dialog.setContentView(layout);

            return dialog;
        }

    }

}
</code></pre>

<p>Hello i am building android app and i am trying to return selected <code>RadioButton</code> id from the custom dialog to the main acivity but the app force closes on this line <code>radioGroup.setOnCheckedChangeListener(new OnCheckedChangeListener()</code></p>

<p>Can somebody give some hints thank you</p>
