Android开发的HTTP Post请求 - 帮助调试

Question

I am attempting to access an Apache server through a button.

I am sending a message to the server and receiving a message back. I am displaying that message on a text field.

My code is not working and I do not know how to debug. I am attaching my code and PHP script. I am a beginner at this so any help will be appreciated.

public class MainActivity extends AppCompatActivity {


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

    }

    public void sendMessage(View view) {

        HttpURLConnection request = null;

        try {
            String myURL = "http://creative.colorado.edu/";
            URL url = new URL(myURL);

            request = (HttpURLConnection) url.openConnection();

            //To post output request
            request.setDoOutput(true);
            request.setRequestMethod("POST");
            request.setRequestProperty("message", "text/plain");

            String input = "I am ok";

            OutputStream outputPost = new BufferedOutputStream(request.getOutputStream());
            outputPost.write(input.getBytes());
            outputPost.flush();
            outputPost.close();

            BufferedReader in = new BufferedReader(new InputStreamReader(request.getInputStream()));
            String inputLine;
            while((inputLine = in.readLine()) != null){
                System.out.println(inputLine);
            }

            in.close();

            System.out.println(inputLine);

            TextView displayMessage = (TextView) findViewById(R.id.textView2);
            displayMessage.setText(in.toString());
        }

        catch (Exception ex) {
        }

        finally {
            if (request != null) {
                request.disconnect();
            }
        }

    }
}

Here is the PHP script I am using (I am not certain it is correct):

<?php

//Read request parameters
$message= $_POST[“message”];

// Store values in an array
$returnValue = array(“message”=>$message);

// Send back request in JSON format
echo json_encode($returnValue);

?>

Answer 1

Before you read from the input stream you need to actually make the http call.

...

outputPost.close();

request.connect()

BufferedReader in = new BufferedReader(new InputStreamReader(request.getInputStream())); ...

Also, any network calls need to be made in a background async thread. The Volley (https://developer.android.com/training/volley/simple.html) library makes this work dramatically easier.