I am trying to write an Android app that could communicate over WiFi with ESP8266 module and exchange some simple, basic text data. My problem is I can not get any communication to work. I am not sure if my problem is with the Android code or some bad network configuration on the ESP.
On the Android side, I am using a standard TCPclient class code from this thread to transmit data. In this app I can get WiFi to work and to connect with ESP module using SSID and password authorization.
This is how my app looks like.
Here is TCPclient.java class code I used.
package com.example.wexfo.wifi_com;
import ...
public class TCPclient {
private String serverMessage;
public static final String SERVER_IP = "192.168.0.102";
public static final int SERVER_PORT = 4444;
private OnMessageReceived messageListener = null;
private boolean run = false;
public static final String LOG_TAG = "TCP";
PrintWriter out;
BufferedReader in;
public TCPclient(OnMessageReceived listener) {
messageListener = listener;
}
public void sendMessage(String message) {
if (out != null && !out.checkError()) {
out.println(message);
out.flush();
}
}
public void stopClient() {
run = false;
if (out != null) {
out.flush();
out.close();
}
messageListener = null;
in = null;
out = null;
serverMessage = null;
}
public void run() {
run = true;
try {
InetAddress serverAddress = InetAddress.getByName(SERVER_IP);
Log.e(LOG_TAG, "C: Connecting...");
Socket socket = new Socket(serverAddress, SERVER_PORT);
try {
out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(socket.getOutputStream())), true);
Log.e(LOG_TAG, "C: Sent.");
Log.e(LOG_TAG, "C: Done.");
in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
while (run) {
serverMessage = in.readLine();
if (serverMessage != null && messageListener != null) {
messageListener.messageReceived(serverMessage);
}
//serverMessage = null;
}
Log.e(LOG_TAG, "S: Received message: '" + serverMessage + "'.");
}
catch (Exception e) {
Log.e(LOG_TAG, "S: Error", e);
}
finally {
socket.close();
}
}
catch (Exception e) {
Log.e(LOG_TAG, "C: Error", e);
}
}
public interface OnMessageReceived {
void messageReceived(String message);
}
}
Below is MainActivity.java code.
package com.example.wexfo.wifi_com;
import ...
public class MainActivity extends AppCompatActivity {
// Labels and edits
private TextView connectionText;
private EditText messageText;
private TextView chatText;
// Buttons
private ToggleButton connectButton;
private Button sendButton;
// Wifi connection
private static final String NET_SSID = "AI-THINKER";
private static final String NET_PASSWD = "aiTHINKERwifi";
private WifiConfiguration wifiConfig;
private WifiManager wifiManager;
// Other
private TCPclient tcpClient;
private void printChatLine(String text) {
chatText.append("\n>> " + text);
}
private void printChatLine(String who, String text) {
chatText.append("\n" + who + ": " + text);
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
connectionText = (TextView) findViewById(R.id.connectionText);
messageText = (EditText) findViewById(R.id.messageText);
chatText = (TextView) findViewById(R.id.chatText);
chatText.setMovementMethod(new ScrollingMovementMethod());
printChatLine("chat test");
// WiFi setup (authorization hard-coded for now)
wifiConfig = new WifiConfiguration();
wifiConfig.SSID = "\"" + NET_SSID + "\"";
wifiConfig.preSharedKey = "\"" + NET_PASSWD + "\"";
wifiManager = (WifiManager) getSystemService(Context.WIFI_SERVICE);
wifiManager.addNetwork(wifiConfig);
connectButton = (ToggleButton) findViewById(R.id.connectButton);
connectButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (connectButton.isChecked()) {
connectionText.setText("Disconnect WiFi");
if (!wifiManager.isWifiEnabled())
wifiManager.setWifiEnabled(true);
List<WifiConfiguration> netList = wifiManager.getConfiguredNetworks();
for (WifiConfiguration net : netList) {
if (net.SSID != null && net.SSID.equals("\"" + NET_SSID + "\"")) {
wifiManager.disconnect();
wifiManager.enableNetwork(net.networkId, true);
wifiManager.reconnect();
break;
}
}
// Start server connection thread
new ConnectTask().execute("");
}
else {
connectionText.setText("Connect WiFi");
if (wifiManager.isWifiEnabled())
wifiManager.setWifiEnabled(false);
// Stop server connection thread
if (tcpClient != null)
tcpClient.stopClient();
}
}
});
sendButton = (Button) findViewById(R.id.sendButton);
sendButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String message = messageText.getText().toString();
printChatLine("ME", message);
messageText.setText("");
// Send message to ESP
if (tcpClient != null)
tcpClient.sendMessage(message);
}
});
}
public class ConnectTask extends AsyncTask<String,String,TCPclient> {
@Override
protected TCPclient doInBackground(String... message) {
tcpClient = new TCPclient(new TCPclient.OnMessageReceived() {
@Override
public void messageReceived(String message) {
publishProgress(message);
}
});
tcpClient.run();
return null;
}
@Override
protected void onProgressUpdate(String... values) {
super.onProgressUpdate(values);
// Received message from ESP
printChatLine("ES", values[0]);
}
}
}
Now the ESP8266 is set to work as SoftAP
AT+CWMODE?
+CWMODE:3
OK
Then I make a basic setup for multiple connections and start a new server.
AT+CIPSTA="192.168.0.102"
OK
AT+CIPMUX=1
OK
AT+CIPSERVER=1,4444
OK
Here is my IP data.
AT+CIFSR
+CIFSR:APIP,"192.168.4.1"
+CIFSR:APMAC,"1a:fe:34:8e:81:58"
+CIFSR:STAIP,"192.168.0.102"
+CIFSR:STAMAC,"18:fe:34:8e:81:58"
OK
Now when I run my app I can confirm I am connected to ESP's access point.
AT+CWLIF
192.168.4.2,00:27:15:77:82:02
OK
However there is no sign of an opened connection on the ESP and clicking SEND button does not make any data transfer. When I try to connect through ESP, I get an ERROR.
AT+CIPSTART=0,"TCP","192.168.4.2",4444
0,CLOSED
ERROR
My feeling is the app works fine but I do something horribly wrong on the ESP side and I can not figure out what it is. Maybe I have a wrong idea about the entire setup?
