diff --git a/libs/binder/ndk/include_ndk/android/binder_parcel.h b/libs/binder/ndk/include_ndk/android/binder_parcel.h
index c617898..ed18dee 100644
--- a/libs/binder/ndk/include_ndk/android/binder_parcel.h
+++ b/libs/binder/ndk/include_ndk/android/binder_parcel.h
@@ -55,9 +55,9 @@
 
 /**
  * This is called to allocate a buffer for a C-style string (null-terminated). The returned buffer
- * should be at least length bytes. This includes space for a null terminator. length will always be
- * strictly less than or equal to the maximum size that can be held in a size_t and will always be
- * greater than 0.
+ * should be at least length bytes. This includes space for a null terminator. For a string, length
+ * will always be strictly less than or equal to the maximum size that can be held in a size_t and
+ * will always be greater than 0. However, if a 'null' string is being read, length will be -1.
  *
  * See also AParcel_readString.
  *
@@ -65,31 +65,35 @@
  *
  * \param stringData some external representation of a string
  * \param length the length of the buffer needed to fill (including the null-terminator)
+ * \param buffer a buffer of size 'length' or null if allocation failed.
  *
- * \return a buffer of size 'length' or null if allocation failed.
+ * \return true if the allocation succeeded, false otherwise. If length is -1, a true return here
+ * means that a 'null' value (or equivalent) was successfully stored.
  */
-typedef char* (*AParcel_stringAllocator)(void* stringData, size_t length);
+typedef bool (*AParcel_stringAllocator)(void* stringData, int32_t length, char** buffer);
 
 /**
- * This is called to allocate an array of size 'length'.
+ * This is called to allocate an array of size 'length'. If length is -1, then a 'null' array (or
+ * equivalent) should be created.
  *
  * See also AParcel_readStringArray
  *
  * \param arrayData some external representation of an array
  * \param length the length to allocate this array to
  *
- * \return true if allocation succeeded
+ * \return true if allocation succeeded. If length is -1, a true return here means that a 'null'
+ * value (or equivalent) was successfully stored.
  */
-typedef bool (*AParcel_stringArrayAllocator)(void* arrayData, size_t length);
+typedef bool (*AParcel_stringArrayAllocator)(void* arrayData, int32_t length);
 
 /**
  * This is called to allocate a string inside of an array that was allocated by an
  * AParcel_stringArrayAllocator.
  *
  * The index returned will always be within the range [0, length of arrayData). The returned buffer
- * should be at least length bytes. This includes space for a null-terminator. length will always be
- * strictly less than or equal to the maximum size that can be held in a size_t and will always be
- * greater than 0.
+ * should be at least length bytes. This includes space for a null-terminator. For a string, length
+ * will always be strictly less than or equal to the maximum size that can be held in a size_t and
+ * will always be greater than 0. However, if a 'null' string is being read, length will be -1.
  *
  * See also AParcel_readStringArray
  *
@@ -97,10 +101,13 @@
  * \param index the index at which a string should be allocated.
  * \param length the length of the string to be allocated at this index. See also
  * AParcel_stringAllocator. This includes the length required for a null-terminator.
+ * \param buffer a buffer of size 'length' or null if allocation failed.
  *
- * \return a buffer of size 'length' or null if allocation failed.
+ * \return true if the allocation succeeded, false otherwise. If length is -1, a true return here
+ * means that a 'null' value (or equivalent) was successfully stored.
  */
-typedef char* (*AParcel_stringArrayElementAllocator)(void* arrayData, size_t index, size_t length);
+typedef bool (*AParcel_stringArrayElementAllocator)(void* arrayData, size_t index, int32_t length,
+                                                    char** buffer);
 
 /**
  * This returns the length and buffer of an array at a specific index in an arrayData object.
@@ -110,10 +117,11 @@
  * \param arrayData some external representation of an array.
  * \param index the index at which a string should be allocated.
  * \param outLength an out parameter for the length of the string at the specified index. This
- * should not include the length for a null-terminator if there is one.
+ * should not include the length for a null-terminator if there is one. If the object at this index
+ * is 'null', then this should be set to -1.
  *
  * \param a buffer of size outLength or more representing the string at the provided index. This is
- * not required to be null-terminated.
+ * not required to be null-terminated. If the object at index is null, then this should be null.
  */
 typedef const char* (*AParcel_stringArrayElementGetter)(const void* arrayData, size_t index,
                                                         size_t* outLength);
@@ -367,13 +375,15 @@
 /**
  * Writes utf-8 string value to the next location in a non-null parcel.
  *
+ * If length is -1, and string is nullptr, this will write a 'null' string to the parcel.
+ *
  * \param parcel the parcel to write to.
  * \param string the null-terminated string to write to the parcel, at least of size 'length'.
  * \param length the length of the string to be written.
  *
  * \return STATUS_OK on successful write.
  */
-binder_status_t AParcel_writeString(AParcel* parcel, const char* string, size_t length)
+binder_status_t AParcel_writeString(AParcel* parcel, const char* string, int32_t length)
         __INTRODUCED_IN(29);
 
 /**
@@ -381,7 +391,8 @@
  *
  * Data is passed to the string allocator once the string size is known. This size includes the
  * space for the null-terminator of this string. This allocator returns a buffer which is used as
- * the output buffer from this read.
+ * the output buffer from this read. If there is a 'null' string on the binder buffer, the allocator
+ * will be called with length -1.
  *
  * \param parcel the parcel to read from.
  * \param stringData some external representation of a string.
@@ -397,7 +408,8 @@
  *
  * length is the length of the array. AParcel_stringArrayElementGetter will be called for all
  * indices in range [0, length) with the arrayData provided here. The string length and buffer
- * returned from this function will be used to fill out the data from the parcel.
+ * returned from this function will be used to fill out the data from the parcel. If length is -1,
+ * this will write a 'null' string array to the binder buffer.
  *
  * \param parcel the parcel to write to.
  * \param arrayData some external representation of an array.
@@ -407,7 +419,7 @@
  *
  * \return STATUS_OK on successful write.
  */
-binder_status_t AParcel_writeStringArray(AParcel* parcel, const void* arrayData, size_t length,
+binder_status_t AParcel_writeStringArray(AParcel* parcel, const void* arrayData, int32_t length,
                                          AParcel_stringArrayElementGetter getter)
         __INTRODUCED_IN(29);
 
@@ -418,7 +430,8 @@
  * length is the length of the array to be read from the parcel. Then, for each index i in [0,
  * length), AParcel_stringArrayElementAllocator will be called with the length of the string to be
  * read from the parcel. The resultant buffer from each of these calls will be filled according to
- * the contents of the string that is read.
+ * the contents of the string that is read. If the string array being read is 'null', this will
+ * instead just pass -1 to AParcel_stringArrayAllocator.
  *
  * \param parcel the parcel to read from.
  * \param arrayData some external representation of an array.
diff --git a/libs/binder/ndk/include_ndk/android/binder_parcel_utils.h b/libs/binder/ndk/include_ndk/android/binder_parcel_utils.h
index 657577e..25cc683 100644
--- a/libs/binder/ndk/include_ndk/android/binder_parcel_utils.h
+++ b/libs/binder/ndk/include_ndk/android/binder_parcel_utils.h
@@ -28,6 +28,7 @@
 
 #include <android/binder_parcel.h>
 
+#include <optional>
 #include <string>
 #include <vector>
 
@@ -46,6 +47,8 @@
 }
 
 /**
+ * TODO(b/111445392): delete this function
+ *
  * This allocates a vector to size 'length' and returns whether the allocation is successful.
  *
  * See also AParcel_stdVectorAllocator. Types used with this allocator have their sizes defined
@@ -53,7 +56,6 @@
  * Instead, it is used in cases where callbacks are used.
  *
  * See AParcel_readVector(const AParcel* parcel, std::vector<bool>)
- * See AParcel_readVector(const AParcel* parcel, std::vector<std::string>)
  */
 template <typename T>
 static inline bool AParcel_stdVectorExternalAllocator(void* vectorData, size_t length) {
@@ -65,6 +67,55 @@
 }
 
 /**
+ * This allocates a vector to size 'length' and returns whether the allocation is successful.
+ *
+ * See also AParcel_stdVectorAllocator. Types used with this allocator have their sizes defined
+ * externally with respect to the NDK, and that size information is not passed into the NDK.
+ * Instead, it is used in cases where callbacks are used. Note that when this allocator is used,
+ * null arrays are not supported.
+ *
+ * See AParcel_readVector(const AParcel* parcel, std::vector<std::string>)
+ */
+template <typename T>
+static inline bool AParcel_stdVectorExternalAllocator(void* vectorData, int32_t length) {
+    if (length < 0) return false;
+
+    std::vector<T>* vec = static_cast<std::vector<T>*>(vectorData);
+    if (length > vec->max_size()) return false;
+
+    vec->resize(length);
+    return true;
+}
+
+/**
+ * This allocates a vector to size 'length' and returns whether the allocation is successful.
+ *
+ * See also AParcel_stdVectorAllocator. Types used with this allocator have their sizes defined
+ * externally with respect to the NDK, and that size information is not passed into the NDK.
+ * Instead, it is used in cases where callbacks are used. Note, when this allocator is used,
+ * the vector itself can be nullable.
+ *
+ * See AParcel_readVector(const AParcel* parcel,
+ * std::optional<std::vector<std::optional<std::string>>>)
+ */
+template <typename T>
+static inline bool AParcel_nullableStdVectorExternalAllocator(void* vectorData, int32_t length) {
+    std::optional<std::vector<T>>* vec = static_cast<std::optional<std::vector<T>>*>(vectorData);
+
+    if (length < 0) {
+        *vec = std::nullopt;
+        return true;
+    }
+
+    *vec = std::optional<std::vector<T>>(std::vector<T>{});
+
+    if (length > (*vec)->max_size()) return false;
+    (*vec)->resize(length);
+
+    return true;
+}
+
+/**
  * This retrieves the underlying value in a vector which may not be contiguous at index from a
  * corresponding vectorData.
  */
@@ -110,22 +161,45 @@
  * Allocates a std::string to length and returns the underlying buffer. For use with
  * AParcel_readString. See use below in AParcel_readString(const AParcel*, std::string*).
  */
-static inline char* AParcel_stdStringAllocator(void* stringData, size_t length) {
+static inline bool AParcel_stdStringAllocator(void* stringData, int32_t length, char** buffer) {
+    if (length <= 0) return false;
+
     std::string* str = static_cast<std::string*>(stringData);
     str->resize(length - 1);
-    return &(*str)[0];
+    *buffer = &(*str)[0];
+    return true;
 }
 
 /**
- * Allocates a std::string inside of a std::vector<std::string> at index index to size 'length'.
+ * Allocates a string in a std::optional<std::string> to size 'length' (or to std::nullopt when
+ * length is -1) and returns the underlying buffer. For use with AParcel_readString. See use below
+ * in AParcel_readString(const AParcel*, std::optional<std::string>*).
  */
-static inline char* AParcel_stdVectorStringElementAllocator(void* vectorData, size_t index,
-                                                            size_t length) {
-    std::vector<std::string>* vec = static_cast<std::vector<std::string>*>(vectorData);
+static inline bool AParcel_nullableStdStringAllocator(void* stringData, int32_t length,
+                                                      char** buffer) {
+    if (length == 0) return false;
 
+    std::optional<std::string>* str = static_cast<std::optional<std::string>*>(stringData);
+
+    if (length < 0) {
+        *str = std::nullopt;
+        return true;
+    }
+
+    *str = std::optional<std::string>(std::string{});
+    (*str)->resize(length - 1);
+    *buffer = &(**str)[0];
+    return true;
+}
+
+/**
+ * Allocates a std::string inside of a std::vector<std::string> at index 'index' to size 'length'.
+ */
+static inline bool AParcel_stdVectorStringElementAllocator(void* vectorData, size_t index,
+                                                           int32_t length, char** buffer) {
+    std::vector<std::string>* vec = static_cast<std::vector<std::string>*>(vectorData);
     std::string& element = vec->at(index);
-    element.resize(length - 1);
-    return &element[0];
+    return AParcel_stdStringAllocator(static_cast<void*>(&element), length, buffer);
 }
 
 /**
@@ -135,7 +209,6 @@
 static inline const char* AParcel_stdVectorStringElementGetter(const void* vectorData, size_t index,
                                                                size_t* outLength) {
     const std::vector<std::string>* vec = static_cast<const std::vector<std::string>*>(vectorData);
-
     const std::string& element = vec->at(index);
 
     *outLength = element.size();
@@ -143,6 +216,40 @@
 }
 
 /**
+ * Allocates a string in a std::optional<std::string> inside of a
+ * std::optional<std::vector<std::optional<std::string>>> at index 'index' to size 'length' (or to
+ * std::nullopt when length is -1).
+ */
+static inline bool AParcel_nullableStdVectorStringElementAllocator(void* vectorData, size_t index,
+                                                                   int32_t length, char** buffer) {
+    std::optional<std::vector<std::optional<std::string>>>* vec =
+            static_cast<std::optional<std::vector<std::optional<std::string>>>*>(vectorData);
+    std::optional<std::string>& element = vec->value().at(index);
+    return AParcel_nullableStdStringAllocator(static_cast<void*>(&element), length, buffer);
+}
+
+/**
+ * This gets the length and buffer of a std::optional<std::string> inside of a
+ * std::vector<std::string> at index index. If the string is null, then it returns null and a length
+ * of -1.
+ */
+static inline const char* AParcel_nullableStdVectorStringElementGetter(const void* vectorData,
+                                                                       size_t index,
+                                                                       size_t* outLength) {
+    const std::optional<std::vector<std::optional<std::string>>>* vec =
+            static_cast<const std::optional<std::vector<std::optional<std::string>>>*>(vectorData);
+    const std::optional<std::string>& element = vec->value().at(index);
+
+    if (!element) {
+        *outLength = -1;
+        return nullptr;
+    }
+
+    *outLength = element->size();
+    return element->c_str();
+}
+
+/**
  * Convenience API for writing a std::string.
  */
 static inline binder_status_t AParcel_writeString(AParcel* parcel, const std::string& str) {
@@ -158,6 +265,27 @@
 }
 
 /**
+ * Convenience API for writing a std::optional<std::string>.
+ */
+static inline binder_status_t AParcel_writeString(AParcel* parcel,
+                                                  const std::optional<std::string>& str) {
+    if (!str) {
+        return AParcel_writeString(parcel, nullptr, -1);
+    }
+
+    return AParcel_writeString(parcel, str->c_str(), str->size());
+}
+
+/**
+ * Convenience API for reading a std::optional<std::string>.
+ */
+static inline binder_status_t AParcel_readString(const AParcel* parcel,
+                                                 std::optional<std::string>* str) {
+    void* stringData = static_cast<void*>(str);
+    return AParcel_readString(parcel, stringData, AParcel_nullableStdStringAllocator);
+}
+
+/**
  * Convenience API for writing a std::vector<std::string>
  */
 static inline binder_status_t AParcel_writeVector(AParcel* parcel,
@@ -178,6 +306,28 @@
                                    AParcel_stdVectorStringElementAllocator);
 }
 
+/**
+ * Convenience API for writing a std::optional<std::vector<std::optional<std::string>>>
+ */
+static inline binder_status_t AParcel_writeVector(
+        AParcel* parcel, const std::optional<std::vector<std::optional<std::string>>>& vec) {
+    const void* vectorData = static_cast<const void*>(&vec);
+    return AParcel_writeStringArray(parcel, vectorData, (vec ? vec->size() : -1),
+                                    AParcel_nullableStdVectorStringElementGetter);
+}
+
+/**
+ * Convenience API for reading a std::optional<std::vector<std::optional<std::string>>>
+ */
+static inline binder_status_t AParcel_readVector(
+        const AParcel* parcel, std::optional<std::vector<std::optional<std::string>>>* vec) {
+    void* vectorData = static_cast<void*>(vec);
+    return AParcel_readStringArray(
+            parcel, vectorData,
+            AParcel_nullableStdVectorExternalAllocator<std::optional<std::string>>,
+            AParcel_nullableStdVectorStringElementAllocator);
+}
+
 // @START
 /**
  * Writes a vector of int32_t to the next location in a non-null parcel.
@@ -331,6 +481,23 @@
 }
 
 /**
+ * Convenience API for writing the size of a vector.
+ */
+template <typename T>
+static inline binder_status_t AParcel_writeVectorSize(AParcel* parcel,
+                                                      const std::optional<std::vector<T>>& vec) {
+    if (!vec) {
+        return AParcel_writeInt32(parcel, -1);
+    }
+
+    if (vec->size() > INT32_MAX) {
+        return STATUS_BAD_VALUE;
+    }
+
+    return AParcel_writeInt32(parcel, static_cast<int32_t>(vec->size()));
+}
+
+/**
  * Convenience API for resizing a vector.
  */
 template <typename T>
@@ -345,6 +512,28 @@
     return STATUS_OK;
 }
 
+/**
+ * Convenience API for resizing a vector.
+ */
+template <typename T>
+static inline binder_status_t AParcel_resizeVector(const AParcel* parcel,
+                                                   std::optional<std::vector<T>>* vec) {
+    int32_t size;
+    binder_status_t err = AParcel_readInt32(parcel, &size);
+
+    if (err != STATUS_OK) return err;
+    if (size < -1) return STATUS_UNEXPECTED_NULL;
+
+    if (size == -1) {
+        *vec = std::nullopt;
+        return STATUS_OK;
+    }
+
+    *vec = std::optional<std::vector<T>>(std::vector<T>{});
+    (*vec)->resize(static_cast<size_t>(size));
+    return STATUS_OK;
+}
+
 }  // namespace ndk
 
 /** @} */
diff --git a/libs/binder/ndk/parcel.cpp b/libs/binder/ndk/parcel.cpp
index 53e5010..4136698 100644
--- a/libs/binder/ndk/parcel.cpp
+++ b/libs/binder/ndk/parcel.cpp
@@ -237,9 +237,23 @@
     return PruneStatusT(ret);
 }
 
-binder_status_t AParcel_writeString(AParcel* parcel, const char* string, size_t length) {
-    const uint8_t* str8 = (uint8_t*)string;
+binder_status_t AParcel_writeString(AParcel* parcel, const char* string, int32_t length) {
+    if (string == nullptr) {
+        if (length != -1) {
+            LOG(WARNING) << __func__ << ": null string must be used with length == -1.";
+            return STATUS_BAD_VALUE;
+        }
 
+        status_t err = parcel->get()->writeInt32(-1);
+        return PruneStatusT(err);
+    }
+
+    if (length < 0) {
+        LOG(WARNING) << __func__ << ": Negative string length: " << length;
+        return STATUS_BAD_VALUE;
+    }
+
+    const uint8_t* str8 = (uint8_t*)string;
     const ssize_t len16 = utf8_to_utf16_length(str8, length);
 
     if (len16 < 0 || len16 >= std::numeric_limits<int32_t>::max()) {
@@ -268,7 +282,10 @@
     const char16_t* str16 = parcel->get()->readString16Inplace(&len16);
 
     if (str16 == nullptr) {
-        LOG(WARNING) << __func__ << ": Failed to read string in place.";
+        if (allocator(stringData, -1, nullptr)) {
+            return STATUS_OK;
+        }
+
         return STATUS_UNEXPECTED_NULL;
     }
 
@@ -285,9 +302,10 @@
         return STATUS_BAD_VALUE;
     }
 
-    char* str8 = allocator(stringData, len8);
+    char* str8;
+    bool success = allocator(stringData, len8, &str8);
 
-    if (str8 == nullptr) {
+    if (!success || str8 == nullptr) {
         LOG(WARNING) << __func__ << ": AParcel_stringAllocator failed to allocate.";
         return STATUS_NO_MEMORY;
     }
@@ -297,19 +315,27 @@
     return STATUS_OK;
 }
 
-binder_status_t AParcel_writeStringArray(AParcel* parcel, const void* arrayData, size_t length,
+binder_status_t AParcel_writeStringArray(AParcel* parcel, const void* arrayData, int32_t length,
                                          AParcel_stringArrayElementGetter getter) {
-    if (length > std::numeric_limits<int32_t>::max()) return STATUS_BAD_VALUE;
-
     Parcel* rawParcel = parcel->get();
 
+    if (length < 0) {
+        if (length != -1) {
+            LOG(WARNING) << __func__ << ": null array must be used with length == -1.";
+            return STATUS_BAD_VALUE;
+        }
+
+        status_t status = rawParcel->writeInt32(-1);
+        return PruneStatusT(status);
+    }
+
     status_t status = rawParcel->writeInt32(static_cast<int32_t>(length));
     if (status != STATUS_OK) return PruneStatusT(status);
 
     for (size_t i = 0; i < length; i++) {
         size_t length = 0;
         const char* str = getter(arrayData, i, &length);
-        if (str == nullptr) return STATUS_BAD_VALUE;
+        if (str == nullptr && length != -1) return STATUS_BAD_VALUE;
 
         binder_status_t status = AParcel_writeString(parcel, str, length);
         if (status != STATUS_OK) return status;
@@ -325,10 +351,10 @@
     size_t index;     // index into the string array
     AParcel_stringArrayElementAllocator elementAllocator;
 
-    static char* Allocator(void* stringData, size_t length) {
+    static bool Allocator(void* stringData, int32_t length, char** buffer) {
         StringArrayElementAllocationAdapter* adapter =
                 static_cast<StringArrayElementAllocationAdapter*>(stringData);
-        return adapter->elementAllocator(adapter->arrayData, adapter->index, length);
+        return adapter->elementAllocator(adapter->arrayData, adapter->index, length, buffer);
     }
 };
 
@@ -341,10 +367,12 @@
     status_t status = rawParcel->readInt32(&length);
 
     if (status != STATUS_OK) return PruneStatusT(status);
-    if (length < 0) return STATUS_UNEXPECTED_NULL;
+    if (length < -1) return STATUS_BAD_VALUE;
 
     if (!allocator(arrayData, length)) return STATUS_NO_MEMORY;
 
+    if (length == -1) return STATUS_OK;  // null string array
+
     StringArrayElementAllocationAdapter adapter{
             .arrayData = arrayData,
             .index = 0,
@@ -352,8 +380,10 @@
     };
 
     for (; adapter.index < length; adapter.index++) {
-        AParcel_readString(parcel, static_cast<void*>(&adapter),
-                           StringArrayElementAllocationAdapter::Allocator);
+        binder_status_t status = AParcel_readString(parcel, static_cast<void*>(&adapter),
+                                                    StringArrayElementAllocationAdapter::Allocator);
+
+        if (status != STATUS_OK) return status;
     }
 
     return STATUS_OK;