This example, scan a range of IPs, to check if it is reachable, in turn to discover connected devices in the same network.
MainActivity.java
package com.blogspot.android_er.androidipscanner;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.Toast;
import java.io.IOException;
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.util.ArrayList;
public class MainActivity extends AppCompatActivity {
private Button btnScan;
private ListView listViewIp;
ArrayList<String> ipList;
ArrayAdapter<String> adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btnScan = (Button)findViewById(R.id.scan);
listViewIp = (ListView)findViewById(R.id.listviewip);
ipList = new ArrayList();
adapter = new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1, android.R.id.text1, ipList);
listViewIp.setAdapter(adapter);
btnScan.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
new ScanIpTask().execute();
}
});
}
private class ScanIpTask extends AsyncTask<Void, String, Void>{
/*
Scan IP 192.168.1.100~192.168.1.110
you should try different timeout for your network/devices
*/
static final String subnet = "192.168.1.";
static final int lower = 100;
static final int upper = 110;
static final int timeout = 5000;
@Override
protected void onPreExecute() {
ipList.clear();
adapter.notifyDataSetInvalidated();
Toast.makeText(MainActivity.this, "Scan IP...", Toast.LENGTH_LONG).show();
}
@Override
protected Void doInBackground(Void... params) {
for (int i = lower; i <= upper; i++) {
String host = subnet + i;
try {
InetAddress inetAddress = InetAddress.getByName(host);
if (inetAddress.isReachable(timeout)){
publishProgress(inetAddress.toString());
}
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
return null;
}
@Override
protected void onProgressUpdate(String... values) {
ipList.add(values[0]);
adapter.notifyDataSetInvalidated();
Toast.makeText(MainActivity.this, values[0], Toast.LENGTH_LONG).show();
}
@Override
protected void onPostExecute(Void aVoid) {
Toast.makeText(MainActivity.this, "Done", Toast.LENGTH_LONG).show();
}
}
}
layout/activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
android_layout_width="match_parent"
android_layout_height="match_parent"
android_padding="16dp"
android_orientation="vertical"
tools_context=".MainActivity">
<TextView
android_layout_width="wrap_content"
android_layout_height="wrap_content"
android_layout_gravity="center_horizontal"
android_autoLink="web"
android_text="http://android-er.blogspot.com/"
android_textStyle="bold" />
<Button
android_id="@+id/scan"
android_layout_width="match_parent"
android_layout_height="wrap_content"
android_text="Scan"/>
<ListView
android_id="@+id/listviewip"
android_layout_width="match_parent"
android_layout_height="wrap_content"/>
</LinearLayout>
Permission of "android.permission.INTERNET" is needed in AndroidManifest.xml
<uses-permission android_name="android.permission.INTERNET"/>
Related:
- Java version run on Raspberry Pi - scan connected IP in the same network
