java - Android 应用程序的 android.os.NetworkOnMainThreadException

Question

我正在尝试调用一个包含 json 数据的 url。

String response = null;
    try {
        URL url = new URL("https://demorul.com");
        HttpURLConnection conn = (HttpURLConnection) url.openConnection();
        conn.setReadTimeout(10000);
        conn.setConnectTimeout(10000);
        conn.setRequestMethod("GET");
        conn.setRequestProperty("Content-Type", "application/json;odata=verbose");
        conn.setRequestProperty("Accept", "application/json;odata=verbose");

        // read the response
        InputStream in = new BufferedInputStream(conn.getInputStream());
        response = convertStreamToString(in);
    } catch (MalformedURLException e) {
        Log.e(TAG, "MalformedURLException: " + e.getMessage());
    } catch (ProtocolException e) {
        Log.e(TAG, "ProtocolException: " + e.getMessage());
    } catch (IOException e) {
        Log.e(TAG, "IOException: " + e.getMessage());
    } catch (Exception e) {
        Log.e(TAG, "Exception: " + e.getMessage());
    }
    return response;

该url将返回json数据。但我收到 android.os.NetworkOnMainThreadException 错误意味着它转到最后一个 catch 语句。

在我设置的 AndroidManifest.xml 文件中

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

谢谢

Answer 1

当应用程序尝试在其主线程上执行网络操作时，会引发此异常。在 AsyncTask

中运行代码