android - Leaking window when changing orientation

Question

I'm popping up an AlertDialog so users can type in a new item to add to a list. However, whenever the screen orientation changes, the LogCat spits out a bunch of errors regarding a window leak. I can't quite figure out what I'm doing wrong here.

private void launchPopup() {
    if (mTypedText == null) {
        mTypedText = "";
    }

    LayoutInflater inflater = (LayoutInflater) ActivityTags.this.getSystemService(LAYOUT_INFLATER_SERVICE);
    View layout = inflater.inflate(R.layout.layout_additem, (ViewGroup) findViewById(R.id.additem_root));

    final TextView text = (TextView)layout.findViewById(R.id.additem_text);
    text.setText("Type in the name of the new item.");
    text.setLines(1);

    final EditText name = (EditText)layout.findViewById(R.id.additem_name);
    name.addTextChangedListener(new TextWatcher() {
        public void onTextChanged(CharSequence s, int start, int before, int count) {}

        public void beforeTextChanged(CharSequence s, int start, int count, int after) {}

        public void afterTextChanged(Editable s) {
            if (s != null) {
                mTypedText = s.toString();
            }
            else {
                mTypedText = null;
            }
        }
    });
    if (mTypedText != null) {
        name.setText(mTypedText);
    }

    mAddDialog = new AlertDialog.Builder(ActivityItems.this);
    mAddDialog.setTitle("Add Item");
    mAddDialog.setView(layout);
    mAddDialog.setPositiveButton("Ok", new DialogInterface.OnClickListener() {
    public void onClick(DialogInterface dialogInterface, int i) {
        // TODO
    }
});
    mAddDialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
    public void onClick(DialogInterface dialogInterface, int i) {
        mTypedText = null;
    }
});
    mAddDialog.show();
}

In onStop(), mAddDialog is set to null if it is not already null.

Here is the error:

Activity com.myapp.app.activity.ActivityItems has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@45164f30 that was originally added here
android.view.WindowLeaked: Activity com.myapp.app.activity.ActivityItems has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@45164f30 that was originally added here
at android.view.ViewRoot.<init>(ViewRoot.java:247)
at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:148)
at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:91)
at android.view.Window$LocalWindowManager.addView(Window.java:424)
at android.app.Dialog.show(Dialog.java:241)
at android.app.AlertDialog$Builder.show(AlertDialog.java:802)
...