java.net.SocketException : socket failed: EACCES (Permission denied) not solved by uses-permission

Question

我刚刚开始学习 Android，我正在尝试从 UDP 客户端成功发送字符串

我正在使用PacketSender作为服务器，但到目前为止我还没有得到，因为我的许可被拒绝。

代码如下:

public class UDPStringSender extends AppCompatActivity {


Intent intent;
String ipAddress, port;
int portNumber;

boolean shouldLog;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_udp_string_sender);

    intent = getIntent();
    ipAddress = intent.getStringExtra("ip");
    port = intent.getStringExtra("port");
    portNumber = Integer.parseInt(port);

    Log.d("IP number is", ipAddress);
    Log.d("Port number is", port);

    shouldLog = true;
}


public void sendString(View view) {
    EditText stringField = (EditText)findViewById(R.id.sendableString);
    String sendableString = stringField.getText().toString();

    DatagramSocket _datagramSocket = null;
    try {
        _datagramSocket = new DatagramSocket();

        InetAddress serverIP = InetAddress.getByName(ipAddress);
        if(shouldLog)
            Log.d("InetAddress is", serverIP.toString());
        DatagramPacket _datagramPacket = new DatagramPacket(sendableString.getBytes(), sendableString.length(), serverIP, portNumber);
        if(shouldLog)
            Log.d("Packet to be send", _datagramPacket.toString());
        _datagramSocket.send(_datagramPacket);

    } catch (UnknownHostException e) {
        e.printStackTrace();
    } catch (SocketException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        if(_datagramSocket != null) {
            _datagramSocket.close();
            if(shouldLog)
                Log.d("is datagramSockedClosed", String.valueOf(_datagramSocket.isClosed()));
        }
    }
}

}

我的 Android list :

<?xml version="1.0" encoding="utf-8"?>

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
    <activity android:name=".Interface">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
    <activity android:name=".UDPStringSender">
    </activity>
</application>

以及我的 logcat:

11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err:  java.net.SocketException: socket failed: EACCES (Permission denied)
11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err:     at libcore.io.IoBridge.socket(IoBridge.java:619)
11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err:     at java.net.PlainDatagramSocketImpl.create(PlainDatagramSocketImpl.java:93)
11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err:     at java.net.DatagramSocket.createSocket(DatagramSocket.java:157)
11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err:     at java.net.DatagramSocket.<init>(DatagramSocket.java:80)
11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err:     at java.net.DatagramSocket.<init>(DatagramSocket.java:65)
11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err:     at co.barakastudio.layouttest.UDPStringSender.sendString(UDPStringSender.java:48)
11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err:     at java.lang.reflect.Method.invoke(Native Method)
11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err:     at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288)
11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err:     at android.view.View.performClick(View.java:5697)
11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err:     at android.widget.TextView.performClick(TextView.java:10826)
11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err:     at android.view.View$PerformClick.run(View.java:22526)
11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err:     at android.os.Handler.handleCallback(Handler.java:739)
11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err:     at android.os.Handler.dispatchMessage(Handler.java:95)
11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err:     at android.os.Looper.loop(Looper.java:158)
11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err:     at android.app.ActivityThread.main(ActivityThread.java:7225)
11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err:     at java.lang.reflect.Method.invoke(Native Method)
11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err:     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)
11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)
11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err: Caused by: android.system.ErrnoException: socket failed: EACCES (Permission denied)
11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err:     at libcore.io.Posix.socket(Native Method)
11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err:     at libcore.io.BlockGuardOs.socket(BlockGuardOs.java:282)
11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err:     at libcore.io.IoBridge.socket(IoBridge.java:604)
11-23 15:58:50.652 31936-31936/co.barakastudio.layouttest W/System.err:     ... 17 more

我真的很感谢您的时间，因为它会节省我的大量时间:)干杯，

Answer 1

引用myself :

<uses-permission>元素应位于 <manifest> 内元素，但在 <application> 之外元素。换句话说，这很好:

<?xml version="1.0" encoding="utf-8"?>
<manifest
  package="com.commonsware.android.something.something"
  xmlns:android="http://schemas.android.com/apk/res/android">

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

  <application
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme">

    <!-- cool stuff goes here -->

  </application>

</manifest>

但这不是:

<?xml version="1.0" encoding="utf-8"?>
<manifest
  package="com.commonsware.android.something.something"
  xmlns:android="http://schemas.android.com/apk/res/android">

  <application
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme">

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

    <!-- cool stuff goes here -->

  </application>

</manifest>

如果您手动分析您的 Android Studio 会报告此情况 list (从主菜单分析>检查代码...)，它不会只需将元素放在错误的地方。