java - 无法获取响应/状态代码，使用 HttpUrlConnection 总是得到空白异常

Question

我不知道发生了什么，但我的代码无法获取响应/状态代码，并且总是出现空白异常。

if (!GetS1.isEmpty() || !GetS1.equals("")) {
            runOnUiThread(new Runnable() {
                @Override
                public void run() {
                    try {
                        url = new URL(GetS1);
                        HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
                        urlConnection.setConnectTimeout(2000);
                        urlConnection.setReadTimeout(2000);
                        urlConnection.connect();
                        final int responseCode = urlConnection.getResponseCode();
                        if (responseCode == HttpURLConnection.HTTP_OK) {
                            ButtonS1.setEnabled(true);
                            ButtonS1.setText("ACTIVE");
                        } else if (responseCode == HttpURLConnection.HTTP_FORBIDDEN) {
                            ButtonS1.setText("BLOCKED");
                        } else if (responseCode == HttpURLConnection.HTTP_NOT_FOUND) {
                            ButtonS1.setText("DOWN");
                        } else {
                            ButtonS1.setText("UNKNOWN / BROKEN");
                        }
                    } catch (Exception e) {
                        Toast.makeText(Act_Details.this, e.getMessage(), Toast.LENGTH_SHORT).show();
                    }
                }
            });
        }

我错过了什么吗？我已经在 list 中设置了使用互联网的权限

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

Answer 1

首先，请发布完整的代码，或者至少发布上述代码(您提供的)所属的代码，假设您在一个单独的线程而不是 UI 线程中完成整个工作，您可以这样做:

    if (!GetS1.isEmpty() || !GetS1.equals("")) {
        doNetworkCall();
    }

然后创建一个方法:

    private void doNetworkCall(){

    try {
        url = new URL(GetS1);
        HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
        urlConnection.setConnectTimeout(2000);
        urlConnection.setReadTimeout(2000);
        urlConnection.connect();
        final int responseCode = urlConnection.getResponseCode();
        if (responseCode == HttpURLConnection.HTTP_OK) {
            ButtonS1.setEnabled(true);
            ButtonS1.setText("ACTIVE");
        } 
        else if (responseCode == HttpURLConnection.HTTP_FORBIDDEN) {
            ButtonS1.setText("BLOCKED");
        }
        else if (responseCode == HttpURLConnection.HTTP_NOT_FOUND) {
            ButtonS1.setText("DOWN");
        } 
        else {
            ButtonS1.setText("UNKNOWN / BROKEN");
            }
        } catch (Exception e) {

        Toast.makeText(Act_Details.this, ""+e,Toast.LENGTH_SHORT).show();
                    }
        }

并检查屏幕上是否出现 Toast 并出现错误