B4R Question Simple communication from Android(B4A) to ESP8266

Baublanc

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Longtime User
Allo Everybody, I create a simple app to put the internal led on/off (LED_BUILTIN). With a browser everything work fine (http://192.168.4.2/Gate/on and http://192.168.4.2/Gate/off), but with the B4A app nothing works. The led don't come On.

B4A:
Sub btnGate_Click
    
    Dim j As HttpJob
    j.Initialize("", Me)
    j.Download("http://192.168.4.2/Gate/on")
    Wait For (j) JobDone(j As HttpJob)
    If j.Success Then
        Log(j.GetString)
    End If
    j.Release
    
End Sub

Note: At the location of theESP8266 there no internet.

Thanks
 

miker2069

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Longtime User
It might be better to post the receive code from the B4R code - in the B4R code are you logging connections, does it even attempt to make a connection. Could it be permissions issues on the Andriod side? I haven't done any B4A in a while but I vaguely remember there being something where you have to explicitly request permission for http connections to ip addresses ...
 
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Baublanc

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Longtime User
On the Arduino everything woks fine. here the code:
B4X:
#include <ESP8266WiFi.h>

// Replace with your network credentials
const char* ssid     = "Chalet_Gate";

// Set web server port number to 80
WiFiServer server(80);

IPAddress local_IP(192,168,4,2);
IPAddress gateway(192,168,4,1);
IPAddress subnet(255,255,255,0);

// Variable to store the HTTP request
String header;

// Auxiliar variables to store the current output state
String GateState = "off";

// Assign output variables to GPIO pins
const int output26 = 26;
const int output27 = 27;

void setup() {
  Serial.begin(115200);
 
  Serial.print("Setting AP (Access Point)…");
  // Remove the password parameter, if you want the AP (Access Point) to be open

  // Connect to Wi-Fi network with SSID and password
  Serial.print("Setting soft-AP configuration ... ");
  Serial.println(WiFi.softAPConfig(local_IP, gateway, subnet) ? "Ready" : "Failed!");
 
  WiFi.softAP(ssid);

  IPAddress IP = WiFi.softAPIP();
  Serial.print("AP IP address: ");
  Serial.println(IP);
 
  server.begin();

  pinMode(LED_BUILTIN, OUTPUT);
  digitalWrite(LED_BUILTIN, HIGH);
}

void loop(){
 
  WiFiClient client = server.available();   // Listen for incoming clients

  if (client) {                             // If a new client connects,
    Serial.println("New Client.");          // print a message out in the serial port
    String currentLine = "";                // make a String to hold incoming data from the client
    while (client.connected()) {            // loop while the client's connected
      if (client.available()) {             // if there's bytes to read from the client,
        char c = client.read();             // read a byte, then
        Serial.write(c);                    // print it out the serial monitor
        header += c;
        if (c == '\n') {                    // if the byte is a newline character
          // if the current line is blank, you got two newline characters in a row.
          // that's the end of the client HTTP request, so send a response:
          if (currentLine.length() == 0) {
            // HTTP headers always start with a response code (e.g. HTTP/1.1 200 OK)
            // and a content-type so the client knows what's coming, then a blank line:
            client.println("HTTP/1.1 200 OK");
            client.println("Content-type:text/html");
            client.println("Connection: close");
            client.println();
            
            // turns the GPIOs on and off
            if (header.indexOf("GET /Gate/on") >= 0) {
              Serial.println("Gate on");
              GateState = "on";
              digitalWrite(LED_BUILTIN, LOW);
              //delay(10000);
              //digitalWrite(LED_BUILTIN, HIGH);
            } else if (header.indexOf("GET /Gate/off") >= 0) {
              Serial.println("Gate off");
              GateState = "off";
              digitalWrite(LED_BUILTIN, HIGH);
            }
            
            // Display the HTML web page
            client.println("<!DOCTYPE html><html>");
            client.println("<head><meta name=\"viewport\" content=\"width=device-width, initial-scale=1\">");
            client.println("<link rel=\"icon\" href=\"data:,\">");
            // CSS to style the on/off buttons
            // Feel free to change the background-color and font-size attributes to fit your preferences
            client.println("<style>html { font-family: Helvetica; display: inline-block; margin: 0px auto; text-align: center;}");
            client.println(".button { background-color: #4CAF50; border: none; color: white; padding: 16px 40px;");
            client.println("text-decoration: none; font-size: 30px; margin: 2px; cursor: pointer;}");
            client.println(".button2 {background-color: #555555;}</style></head>");
            
            // Web Page Heading
            client.println("<body><h1>Chalet Gate</h1>");
            
            // Display current state, and ON/OFF buttons for GPIO 26 
            client.println("<p>Gate - State " + GateState + "</p>");
            // If the output26State is off, it displays the ON button       
            if (GateState=="off") {
              client.println("<p><a href=\"/Gate/on\"><button class=\"button\">ON</button></a></p>");
            } else {
              client.println("<p><a href=\"/Gate/off\"><button class=\"button button2\">OFF</button></a></p>");
            }
 
            client.println("</body></html>");
            
            // The HTTP response ends with another blank line
            client.println();
            // Break out of the while loop
            break;
          } else { // if you got a newline, then clear currentLine
            currentLine = "";
          }
        } else if (c != '\r') {  // if you got anything else but a carriage return character,
          currentLine += c;      // add it to the end of the currentLine
        }
      }
    }
    // Clear the header variable
    header = "";
    // Close the connection
    client.stop();
    Serial.println("Client disconnected.");
    Serial.println("");
  }
}

B4A:
Sub Globals

    Private btnGate As Button
    
End Sub

Sub Activity_Create(FirstTime As Boolean)

    Activity.LoadLayout("Main")

End Sub

Sub btnGate_Click
    
    Dim j As HttpJob
    j.Initialize("", Me)
    j.Download("http://192.168.4.2/Gate/on")
    Wait For (j) JobDone(j As HttpJob)
    If j.Success Then
        Log(j.GetString)
    End If
    j.Release
    
End Sub
 
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