nanohttpd in android wont work

StackOverflow https://stackoverflow.com/questions/17684223

  •  03-06-2022
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Question

I tried to get nanohttpd working under android. I have used this example:

package com.example.android_test;

import java.io.IOException;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Properties;

import com.example.android_test.NanoHTTPD.Response.Status;

import android.app.Activity;
import android.net.wifi.WifiManager;
import android.os.Bundle;
import android.os.Handler;
import android.widget.TextView;

public class MainActivity extends Activity {
  private static final int PORT = 8765;
  private TextView hello;
  private MyHTTPD server;
  private Handler handler = new Handler();

  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    hello = (TextView) findViewById(R.id.hello);
  }

  @Override
  protected void onResume() {
    super.onResume();

    TextView textIpaddr = (TextView) findViewById(R.id.ipaddr);
    WifiManager wifiManager = (WifiManager) getSystemService(WIFI_SERVICE);
    int ipAddress = wifiManager.getConnectionInfo().getIpAddress();
    final String formatedIpAddress = String.format("%d.%d.%d.%d", (ipAddress & 0xff),
        (ipAddress >> 8 & 0xff), (ipAddress >> 16 & 0xff), (ipAddress >> 24 & 0xff));
    textIpaddr.setText("Please access! http://" + formatedIpAddress + ":" + PORT);

    try {
      server = new MyHTTPD();
    } catch (IOException e) {
      e.printStackTrace();
    }
  }

  @Override
  protected void onPause() {
    super.onPause();
    if (server != null)
      server.stop();
  }

  private class MyHTTPD extends NanoHTTPD {
    public MyHTTPD() throws IOException {
      super(PORT);
    }

    @Override
    public Response serve(String uri, Method method, Map<String, String> headers,
        Map<String, String> parms, Map<String, String> files) {
      final StringBuilder buf = new StringBuilder();
      for (Entry<String, String> kv : headers.entrySet())
        buf.append(kv.getKey() + " : " + kv.getValue() + "\n");
      handler.post(new Runnable() {
        @Override
        public void run() {
          hello.setText(buf);
        }
      });

      final String html = "<html><head><head><body><h1>Hello, World</h1></body></html>";
      return new NanoHTTPD.Response(Status.OK, MIME_HTML, html);
    }
  }
}

When i start the application on my phone the activity shows the proper ip address. I also can ping the shown address. But when i try to access this via a browser the site will not load. In addition the the above shown MainActivity.java i have only added the NanoHTTPD.java file from the nanohttpd project. Any ideas?

Was it helpful?

Solution

Two things come to mind, both are permissions related. Take a look at your android manifest, you'll want two permissions for your app

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

INTERNET, because you're accessing network services, and WRITE_EXTERNAL_STORAGE because when NanoHttpd receives an incoming connection it writes temp files and most / all phones map the "java.io.tmpdir" to point at the SD card.

See if that helps.

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