fix(android): unbreak perry-ui-android build and wire Picker onChange

changelog.d/8080-android-picker-callback-and-json-extract-pointer.md

@@ -0,0 +1,19 @@
+Fixed two Android defects that made `perry-ui-android` unbuildable and stopped
+`Picker` from reporting selection changes.
+
+`crates/perry-ui-android/src/json.rs` still called the `is_raw_pointer` helper
+that #7448 deleted, so the crate failed to compile for any Android target
+(`error[E0425]: cannot find function is_raw_pointer`). #7448 converted the
+object path to `extract_pointer` but not the array-element path. Routing it
+through the same helper also extends the #7447 fix to array elements: the old
+bit test is the IEEE-754 positive-subnormal predicate, so every positive
+denormal element in a stringified array was classified as a pointer and
+dereferenced.
+
+`PerryBridge.setSpinnerCallback` did not exist. `widgets/picker.rs` has always
+called it over JNI and discarded the resulting error with `let _ =`, so
+`Picker`'s `onChange` could never fire on Android — the widget rendered and
+selected, and the app was simply never told.
+
+Neither showed up in CI because the Android jobs in `feature-matrix.yml` are
+`continue-on-error: true` and push-only.

crates/perry-ui-android/src/json.rs

@@ -552,12 +552,14 @@ unsafe fn stringify_array(ptr: *const u8, buf: &mut String) {
             buf.push_str("true");
         } else if elem_bits == TAG_FALSE {
             buf.push_str("false");
-        } else if elem_tag == POINTER_TAG || is_raw_pointer(elem_bits) {
-            let elem_ptr = if elem_tag == POINTER_TAG {
-                (elem_bits & POINTER_MASK) as *const u8
-            } else {
-                elem_bits as *const u8
-            };
+        // #7448 converted the object path to `extract_pointer` but left this
+        // array-element path calling the `is_raw_pointer` it deleted, so
+        // perry-ui-android stopped compiling for any Android target. Routing
+        // it through the same helper also gives array elements the fix the
+        // object path already had: the old bit test was the IEEE-754
+        // positive-subnormal predicate, so every positive denormal element was
+        // classified as a pointer and dereferenced (#7447).
+        } else if let Some(elem_ptr) = extract_pointer(elem_bits) {
             if is_object_pointer(elem_ptr) {
                 stringify_object(elem_ptr, buf);
             } else {

crates/perry-ui-android/template/app/src/main/java/com/perry/app/PerryBridge.kt

@@ -426,6 +426,38 @@ object PerryBridge {
         seekBar.progress = progress
     }
 
+    // --- Spinner (Picker) callback ---
+
+    // `perry-ui-android`'s picker.rs has always called this, but it was never
+    // defined here and the Rust side discarded the resulting JNI error with
+    // `let _ =` — so `Picker`'s onChange could not fire on Android at all.
+    @JvmStatic
+    fun setSpinnerCallback(spinner: Spinner, callbackKey: Long) {
+        // Spinner calls the listener once when an adapter installs the initial
+        // selection, and again for every later `setAdapter` — `pickerAddItem`
+        // rebuilds the adapter per item. None of those is a user choice, so
+        // report only actual changes, with the first one taken as the baseline.
+        var reported = -1
+        spinner.onItemSelectedListener = object : AdapterView.OnItemSelectedListener {
+            override fun onItemSelected(
+                parent: AdapterView<*>?,
+                view: View?,
+                position: Int,
+                id: Long
+            ) {
+                if (reported == -1) {
+                    reported = position
+                    return
+                }
+                if (position == reported) return
+                reported = position
+                nativeInvokeCallback1(callbackKey, position.toDouble())
+            }
+
+            override fun onNothingSelected(parent: AdapterView<*>?) {}
+        }
+    }
+
     // --- Context menu ---
 
     @JvmStatic