Unable to add window -- token null is not for an application

在使用一個自定義dialog報錯Unable to add window -- token null is not for an application

captchaDialog = new GyHardCaptchaDialog(this.getApplicationContext(), new GyBaseCaptchaDialog.CaptchaListener() {
    @Override
    public void getCaptcha(String captcha, String captchaCookie) {
        LogUtil.e("驗證碼is"+ captcha);
    }
});

Application是全局的，dialog應該附加在一個窗體上，修改爲Activity.this就可以了

captchaDialog = new GyHardCaptchaDialog(AccountLoginActivity.this, new GyBaseCaptchaDialog.CaptchaListener() {
    @Override
    public void getCaptcha(String captcha, String captchaCookie) {
        LogUtil.e("驗證碼is"+ captcha);
    }
});