OkHttp3 response.body().string() always returns empty

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.util.Log;
import android.widget.TextView;

import org.jetbrains.annotations.NotNull;

import java.io.IOException;
import java.io.Reader;

import okhttp3.Call;
import okhttp3.Callback;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;
import okhttp3.ResponseBody;

public class MainActivity extends AppCompatActivity {

    TextView title;
    TextView instructions;

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

        title = findViewById(R.id.titleView);
        instructions = findViewById(R.id.instructionsView);

        OkHttpClient client = new OkHttpClient();

        String url = "https://spoonacular-recipe-food-nutrition-v1.p.rapidapi.com/recipes/findByIngredients?number=1&ranking=1&ignorePantry=false&ingredients=apple%252Csugar%252Csalt";
        Request request = new Request.Builder()
                .url(url)
                .get()
                .addHeader("x-rapidapi-host", "spoonacular-recipe-food-nutrition-v1.p.rapidapi.com")
                .addHeader("x-rapidapi-key", "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx")
                .build();
        client.newCall(request).enqueue(new Callback() {
            @Override
            public void onFailure(@NotNull Call call, @NotNull IOException e) {
                e.printStackTrace();
            }

            @Override
            public void onResponse(@NotNull Call call, @NotNull Response response) throws IOException {
                if (response.isSuccessful()) {
                    String myResponse = response.body().string();
                    Log.i("string", myResponse);
                }
            }
        });
    }
}

The Log output for .toString(): 2020-05-04 19:55:51.801 9894-10024/com.example.testapi I/string: okhttp3.internal.http.RealResponseBody@6314479

The Log output for .string(): 2020-05-04 20:00:39.430 10118-10143/com.example.testapi I/string: []

I know about how OkHttp3 is trying to empty the backing resource as soon as the first .body() call is made, but it's still empty for me.

How can I fix this?

Calling response.body().string() consumes the body - therefore, you can't call it the second time. In the code outside of your snippet , there must be at least one response.body() left.

> The response body can be consumed only once.

https://square.github.io/okhttp/3.x/okhttp/index.html?okhttp3/ResponseBody.html

Fix

Somewhere in your implementation code, response.body() is already called once. Instead replace by response.peekBody().

The solution is to store it in a variable if you need it for further processing.

         @Override
            public void onResponse(@NotNull Call call, @NotNull Response response) throws IOException {
                if (response.isSuccessful()) {
                    String myResponse = response.peekBody(99999L).string();
                    Log.i("string", myResponse);
                }
            }