4 — מאובייקט לגוף בקשת POST

                 android:layout_height="wrap_content"
                 android:accessibilityLiveRegion="polite"
                 android:text="Ready — send a request" />
+            <Button
+                android:id="@+id/postPet"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:text="POST a new classroom cat" />
+            <TextView
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:layout_marginTop="12dp"
+                android:text="Outgoing POST body — serialized object"
+                android:textStyle="bold" />
+            <TextView
+                android:id="@+id/outgoingJson"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:fontFamily="monospace"
+                android:textIsSelectable="true" />
             <TextView
                 android:layout_width="match_parent"
                 android:layout_height="wrap_content"

 import androidx.core.view.ViewCompat;
 import androidx.core.view.WindowInsetsCompat;
 
+import com.android.volley.DefaultRetryPolicy;
 import com.android.volley.NetworkResponse;
 import com.android.volley.Request;
 import com.android.volley.RequestQueue;

 import com.google.gson.Gson;
 import com.google.gson.JsonParseException;
 
+import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Scanner;

         binding.showAvailable.setOnClickListener(v -> showAvailable());
         binding.showAll.setOnClickListener(v -> renderPets(pets));
         binding.renameFirst.setOnClickListener(v -> renameFirst());
+        binding.postPet.setOnClickListener(v -> postPet());
     }
 
     /** Fetches JSON as text; no Java Pet objects are created here. */

         binding.petTable.addView(row);
     }
 
+    /** Serializes a new animal and sends exactly the text displayed above the response. */
+    private void postPet() {
+        Pet animal = new Pet();
+        animal.id = System.currentTimeMillis();
+        animal.name = "Classroom cat 🐈";
+        animal.status = "available";
+        animal.photoUrls = new String[0];
+        String outgoingJson = gson.toJson(animal);
+        binding.outgoingJson.setText(outgoingJson);
+        queue.cancelAll(this);
+        binding.status.setText("Sending POST...");
+        StringRequest request = new StringRequest(Request.Method.POST,
+                BASE_URL + "/pet", text -> {
+            binding.responseJson.setText(text);
+            binding.status.setText("POST HTTP " + httpStatus + " — returned JSON shown below");
+        }, this::showError) {
+            @Override
+            public Map<String, String> getHeaders() {
+                return Collections.singletonMap("Accept", "application/json");
+            }
+
+            @Override
+            public String getBodyContentType() {
+                return "application/json; charset=UTF-8";
+            }
+
+            @Override
+            public byte[] getBody() {
+                return outgoingJson.getBytes(StandardCharsets.UTF_8);
+            }
+
+            @Override
+            protected Response<String> parseNetworkResponse(NetworkResponse response) {
+                httpStatus = response.statusCode;
+                return Response.success(
+                        new String(response.data, java.nio.charset.StandardCharsets.UTF_8), null);
+            }
+        };
+        request.setRetryPolicy(new DefaultRetryPolicy(10000, 0, 1f));
+        request.setShouldCache(false);
+        request.setTag(this);
+        queue.add(request);
+    }
+
     /** Keeps HTTP error bodies visible and distinguishes them from connection failures. */
     private void showError(VolleyError error) {
         NetworkResponse response = error.networkResponse;