如何解决此“找不到符号方法评估JavaScript”错误？

Question

在webview中，使用对话框启动带有window.open的新窗口。 按下智能手机的返回键时，尝试如下运行“ javascript：self.close（）”。

newWebView.evaluateJavaScript ("self.close()", null);

顶部有错误。

error: cannot find symbol method evaluateJavaScript (String, <null>)

因此，我将其修改为一个对话框，但是我看到了相同的错误。

dialog.evaluateJavaScript ("self.close()", null);

按下返回键并用dialog.dismiss();

关闭时

    webView.setWebChromeClient(new WebChromeClient() {
        @Override
        public boolean onCreateWindow(final WebView view, boolean isDialog, boolean isUserGesture, Message resultMsg) {
            WebView newWebView = new WebView(MainActivity.this);
            WebSettings webSettings = newWebView.getSettings();
            webSettings.setJavaScriptEnabled(true);
            webSettings.setJavaScriptCanOpenWindowsAutomatically(true);
            webSettings.setSupportMultipleWindows(true);

            newWebView.setWebViewClient(new WebViewClient());

            final Dialog dialog = new Dialog(MainActivity.this);
            dialog.setContentView(newWebView);
            dialog.show();

            dialog.setOnKeyListener(new DialogInterface.OnKeyListener() {
                @Override
                public boolean onKey(DialogInterface dialog, int keyCode, KeyEvent event) {
                    if (keyCode == KeyEvent.KEYCODE_HOME) {
                        showGuide("HOME pressed...");
                        return true;
                    }
                    if (keyCode == KeyEvent.KEYCODE_BACK) {
                        //dialog.dismiss();
                        //dialog.cancel();
            // Build.VERSION.SDK_INT : 25
            //        minSdkVersion 15
            //        targetSdkVersion 28
                        MainActivity.this.runOnUiThread(new Runnable() {
                            public void run() {
                                try {
                                    dialog.evaluateJavaScript("self.close()", null); // 여기서 에러가 납니다.
                                } catch (Exception e) {
                                    Log.d("scriptCall", e.toString());
                                }
                            }
                        });

                        showGuide("KEYCODE_BACK pressed...");
                        return true;
                    }
                    return false;
                }
            });

            newWebView.setWebChromeClient(new WebChromeClient() {
                @Override
                public void onCloseWindow(WebView window) {
                    super.onCloseWindow(window);
                    dialog.dismiss();
                }
            });

            ((WebView.WebViewTransport) resultMsg.obj).setWebView(newWebView);
            resultMsg.sendToTarget();
            return true;
        }
    });