求助：socket调用触发libcore.io.ErrnoException权限拒绝问题

Hey there, sorry to hear you're stuck with this stubborn socket permission error—let's walk through some common (and easy-to-miss) fixes that might resolve your issue, even if you've already tried basic permission additions.

1. Double-Check Permission Placement & Required Permissions #

First, make sure your permissions are declared in the right spot in your AndroidManifest.xml. They need to be direct children of the <manifest> tag, not nested inside <application> or any other component.

You'll definitely need this core permission:

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

If your app needs to check network state before creating the socket, add this too:

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

2. Avoid Privileged Port Numbers #

If you're trying to bind to or connect to a port below 1024 (like 80, 21, etc.), regular Android apps don't have permission to use these—they're reserved for system-level processes. Switch to a port number 1024 or higher (e.g., 8080, 9000) and test again.

3. Account for Android Version-Specific Restrictions #

Different Android versions have stricter network rules that might be blocking your socket:

• Android 9 (API 28)+: If your targetSdkVersion is 28 or higher, and you're using unencrypted socket connections, ensure you've enabled cleartext traffic in your <application> tag:

  <application
      ...
      android:usesCleartextTraffic="true">
  

• Android 10 (API 29)+: If your app is running in the background, it might be restricted from accessing the network. To fix this, either:
  • Use a foreground service with a notification to keep network access active
  • Request the REQUEST_IGNORE_BATTERY_OPTIMIZATIONS permission to avoid battery saver blocking network
• Android 11+: Check if your app has been granted network permissions in Settings > Apps > [Your App] > Permissions. Sometimes system updates or app misconfigurations can revoke these automatically.

4. Review Network Security Config #

If you've set up a networkSecurityConfig XML file, ensure it doesn't block outgoing socket connections. For example, if you've restricted domains, make sure your target socket host/IP is allowed, or remove unnecessary restrictions for testing.

5. Verify Socket Implementation in Code #

A few code-related checks:

• Never create or use sockets on the main thread—this can lead to ANRs, and in some cases, indirect permission-related issues. Always use a background thread or coroutine.
• Double-check your socket initialization code. For example, if you're binding to a local address, make sure you're not using InetAddress.getByName("localhost") incorrectly (try using InetAddress.getLoopbackAddress() instead for local connections).

To help narrow this down further, could you share:

• The full content of your AndroidManifest.xml (redact any sensitive info)
• The specific code snippet where you're creating/using the socket
• Your app's targetSdkVersion and the Android version you're testing on

内容的提问来源于stack exchange，提问作者Progga Ilma