Android自定义URLSpan不起作用

问题是要处理我自己的单击URL范围的操作。我编写了自定义URLSpan，但是它不起作用。

这是我的自定义URLSpan：

public class CustomURLSpan extends android.text.style.URLSpan {
    private Command mClickAction;

    public CustomURLSpan(String url, Command clickAction) {
        super(url);
        mClickAction = clickAction;
    }

    @Override
    public void onClick(View widget) {
        try {
            mClickAction.execute();
        } catch (Exception e) {
        }
    }

    public static void clickifyTextView(TextView tv, Command clickAction) {
        SpannableString current = new SpannableString(tv.getText());
        URLSpan[] spans =
                current.getSpans(0, current.length(), URLSpan.class);

        for (URLSpan span : spans) {
            int start = current.getSpanStart(span);
            int end = current.getSpanEnd(span);

            current.removeSpan(span);
            current.setSpan(new CustomURLSpan(span.getURL(), clickAction), start, end, 0);
        }
    }

    public interface Command {
        void execute();
    }
}

在这里我用它：

@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {

    Bundle bundle = getArguments();
    String message = bundle.getString("message");
    final Activity activity = getActivity();
    text = new TextView(activity);
    text.setText(message);

    Linkify.addLinks(text, Linkify.EMAIL_ADDRESSES);
    CustomURLSpan.clickifyTextView(text, new CustomURLSpan.Command() {
        @Override
        public void execute() {
            //I want to do my stuff here, but not working
        }
    });
    AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(getActivity());
    alertDialogBuilder.setView(text);
    alertDialogBuilder.setNegativeButton("Close", new DialogInterface.OnClickListener() {
        ...
}

但是，如果我单击url，我会得到本地android对话框来选择电子邮件程序。我在互联网上找到的所有示例都是相同的。

编辑：根据来自@CommonWare的答案。我只需要：

...
public static void clickifyTextView(TextView tv, Command clickAction) {
    SpannableString current = new SpannableString(tv.getText());
    URLSpan[] spans =
            current.getSpans(0, current.length(), URLSpan.class);

    for (URLSpan span : spans) {
        int start = current.getSpanStart(span);
        int end = current.getSpanEnd(span);

        current.removeSpan(span);
        current.setSpan(new CustomURLSpan(span.getURL(), clickAction), start, end, 0);
        tv.setText(current); //this is what I need
    }
}

public interface Command {
    void execute();
}