diff --git a/native/jni/src/additional_proximity_chars.cpp b/native/jni/src/additional_proximity_chars.cpp
index f594927..661c50e 100644
--- a/native/jni/src/additional_proximity_chars.cpp
+++ b/native/jni/src/additional_proximity_chars.cpp
@@ -21,23 +21,23 @@
 // TODO: Have proximity character informations in each language's binary dictionary.
 const char *AdditionalProximityChars::LOCALE_EN_US = "en";
 
-const int32_t AdditionalProximityChars::EN_US_ADDITIONAL_A[EN_US_ADDITIONAL_A_SIZE] = {
+const int AdditionalProximityChars::EN_US_ADDITIONAL_A[EN_US_ADDITIONAL_A_SIZE] = {
     'e', 'i', 'o', 'u'
 };
 
-const int32_t AdditionalProximityChars::EN_US_ADDITIONAL_E[EN_US_ADDITIONAL_E_SIZE] = {
+const int AdditionalProximityChars::EN_US_ADDITIONAL_E[EN_US_ADDITIONAL_E_SIZE] = {
     'a', 'i', 'o', 'u'
 };
 
-const int32_t AdditionalProximityChars::EN_US_ADDITIONAL_I[EN_US_ADDITIONAL_I_SIZE] = {
+const int AdditionalProximityChars::EN_US_ADDITIONAL_I[EN_US_ADDITIONAL_I_SIZE] = {
     'a', 'e', 'o', 'u'
 };
 
-const int32_t AdditionalProximityChars::EN_US_ADDITIONAL_O[EN_US_ADDITIONAL_O_SIZE] = {
+const int AdditionalProximityChars::EN_US_ADDITIONAL_O[EN_US_ADDITIONAL_O_SIZE] = {
     'a', 'e', 'i', 'u'
 };
 
-const int32_t AdditionalProximityChars::EN_US_ADDITIONAL_U[EN_US_ADDITIONAL_U_SIZE] = {
+const int AdditionalProximityChars::EN_US_ADDITIONAL_U[EN_US_ADDITIONAL_U_SIZE] = {
     'a', 'e', 'i', 'o'
 };
 } // namespace latinime
diff --git a/native/jni/src/additional_proximity_chars.h b/native/jni/src/additional_proximity_chars.h
index 0333c2d..21eb0bf 100644
--- a/native/jni/src/additional_proximity_chars.h
+++ b/native/jni/src/additional_proximity_chars.h
@@ -18,7 +18,6 @@
 #define LATINIME_ADDITIONAL_PROXIMITY_CHARS_H
 
 #include <cstring>
-#include <stdint.h>
 
 #include "defines.h"
 
@@ -29,15 +28,15 @@
     DISALLOW_IMPLICIT_CONSTRUCTORS(AdditionalProximityChars);
     static const char *LOCALE_EN_US;
     static const int EN_US_ADDITIONAL_A_SIZE = 4;
-    static const int32_t EN_US_ADDITIONAL_A[];
+    static const int EN_US_ADDITIONAL_A[];
     static const int EN_US_ADDITIONAL_E_SIZE = 4;
-    static const int32_t EN_US_ADDITIONAL_E[];
+    static const int EN_US_ADDITIONAL_E[];
     static const int EN_US_ADDITIONAL_I_SIZE = 4;
-    static const int32_t EN_US_ADDITIONAL_I[];
+    static const int EN_US_ADDITIONAL_I[];
     static const int EN_US_ADDITIONAL_O_SIZE = 4;
-    static const int32_t EN_US_ADDITIONAL_O[];
+    static const int EN_US_ADDITIONAL_O[];
     static const int EN_US_ADDITIONAL_U_SIZE = 4;
-    static const int32_t EN_US_ADDITIONAL_U[];
+    static const int EN_US_ADDITIONAL_U[];
 
     AK_FORCE_INLINE static bool isEnLocale(const char *localeStr) {
         const size_t LOCALE_EN_US_SIZE = strlen(LOCALE_EN_US);
@@ -46,7 +45,7 @@
     }
 
  public:
-    static int getAdditionalCharsSize(const char *localeStr, const int32_t c) {
+    static int getAdditionalCharsSize(const char *localeStr, const int c) {
         if (!isEnLocale(localeStr)) {
             return 0;
         }
@@ -66,7 +65,7 @@
         }
     }
 
-    static const int32_t *getAdditionalChars(const char *localeStr, const int32_t c) {
+    static const int *getAdditionalChars(const char *localeStr, const int c) {
         if (!isEnLocale(localeStr)) {
             return 0;
         }
diff --git a/native/jni/src/proximity_info.cpp b/native/jni/src/proximity_info.cpp
index 84db7c1..d38ea67 100644
--- a/native/jni/src/proximity_info.cpp
+++ b/native/jni/src/proximity_info.cpp
@@ -66,7 +66,7 @@
           HAS_TOUCH_POSITION_CORRECTION_DATA(keyCount > 0 && keyXCoordinates && keyYCoordinates
                   && keyWidths && keyHeights && keyCharCodes && sweetSpotCenterXs
                   && sweetSpotCenterYs && sweetSpotRadii),
-          mProximityCharsArray(new int32_t[GRID_WIDTH * GRID_HEIGHT * MAX_PROXIMITY_CHARS_SIZE
+          mProximityCharsArray(new int[GRID_WIDTH * GRID_HEIGHT * MAX_PROXIMITY_CHARS_SIZE
                   /* proximityGridLength */]),
           mCodeToKeyMap() {
     const int proximityGridLength = GRID_WIDTH * GRID_HEIGHT * MAX_PROXIMITY_CHARS_SIZE;
@@ -115,7 +115,7 @@
     if (DEBUG_PROXIMITY_INFO) {
         AKLOGI("hasSpaceProximity: index %d, %d, %d", startIndex, x, y);
     }
-    int32_t *proximityCharsArray = mProximityCharsArray;
+    int *proximityCharsArray = mProximityCharsArray;
     for (int i = 0; i < MAX_PROXIMITY_CHARS_SIZE; ++i) {
         if (DEBUG_PROXIMITY_INFO) {
             AKLOGI("Index: %d", mProximityCharsArray[startIndex + i]);
@@ -163,14 +163,14 @@
 }
 
 void ProximityInfo::calculateNearbyKeyCodes(
-        const int x, const int y, const int32_t primaryKey, int *inputCodes) const {
-    int32_t *proximityCharsArray = mProximityCharsArray;
+        const int x, const int y, const int primaryKey, int *inputCodes) const {
+    int *proximityCharsArray = mProximityCharsArray;
     int insertPos = 0;
     inputCodes[insertPos++] = primaryKey;
     const int startIndex = getStartIndexFromCoordinates(x, y);
     if (startIndex >= 0) {
         for (int i = 0; i < MAX_PROXIMITY_CHARS_SIZE; ++i) {
-            const int32_t c = proximityCharsArray[startIndex + i];
+            const int c = proximityCharsArray[startIndex + i];
             if (c < KEYCODE_SPACE || c == primaryKey) {
                 continue;
             }
@@ -198,13 +198,13 @@
                 return;
             }
 
-            const int32_t *additionalProximityChars =
+            const int *additionalProximityChars =
                     AdditionalProximityChars::getAdditionalChars(mLocaleStr, primaryKey);
             for (int j = 0; j < additionalProximitySize; ++j) {
-                const int32_t ac = additionalProximityChars[j];
+                const int ac = additionalProximityChars[j];
                 int k = 0;
                 for (; k < insertPos; ++k) {
-                    if (static_cast<int>(ac) == inputCodes[k]) {
+                    if (ac == inputCodes[k]) {
                         break;
                     }
                 }
@@ -235,7 +235,7 @@
     if (c == NOT_A_CODE_POINT) {
         return NOT_AN_INDEX;
     }
-    const int lowerCode = static_cast<int>(toLowerCase(c));
+    const int lowerCode = toLowerCase(c);
     hash_map_compat<int, int>::const_iterator mapPos = mCodeToKeyMap.find(lowerCode);
     if (mapPos != mCodeToKeyMap.end()) {
         return mapPos->second;
@@ -254,7 +254,7 @@
     // TODO: Optimize
     for (int i = 0; i < KEY_COUNT; ++i) {
         const int code = mKeyCodePoints[i];
-        const int lowerCode = static_cast<int>(toLowerCase(code));
+        const int lowerCode = toLowerCase(code);
         mCenterXsG[i] = mKeyXCoordinates[i] + mKeyWidths[i] / 2;
         mCenterYsG[i] = mKeyYCoordinates[i] + mKeyHeights[i] / 2;
         mCodeToKeyMap[lowerCode] = i;
diff --git a/native/jni/src/proximity_info.h b/native/jni/src/proximity_info.h
index 7ee15d5..d002283 100644
--- a/native/jni/src/proximity_info.h
+++ b/native/jni/src/proximity_info.h
@@ -17,8 +17,6 @@
 #ifndef LATINIME_PROXIMITY_INFO_H
 #define LATINIME_PROXIMITY_INFO_H
 
-#include <stdint.h>
-
 #include "defines.h"
 #include "hash_map_compat.h"
 #include "jni.h"
@@ -59,7 +57,7 @@
         return mSweetSpotCenterYs[keyIndex];
     }
     void calculateNearbyKeyCodes(
-            const int x, const int y, const int32_t primaryKey, int *inputCodes) const;
+            const int x, const int y, const int primaryKey, int *inputCodes) const;
 
     bool hasTouchPositionCorrectionData() const {
         return HAS_TOUCH_POSITION_CORRECTION_DATA;
@@ -141,12 +139,12 @@
     const int KEYBOARD_HEIGHT;
     const bool HAS_TOUCH_POSITION_CORRECTION_DATA;
     char mLocaleStr[MAX_LOCALE_STRING_LENGTH];
-    int32_t *mProximityCharsArray;
-    int32_t mKeyXCoordinates[MAX_KEY_COUNT_IN_A_KEYBOARD];
-    int32_t mKeyYCoordinates[MAX_KEY_COUNT_IN_A_KEYBOARD];
-    int32_t mKeyWidths[MAX_KEY_COUNT_IN_A_KEYBOARD];
-    int32_t mKeyHeights[MAX_KEY_COUNT_IN_A_KEYBOARD];
-    int32_t mKeyCodePoints[MAX_KEY_COUNT_IN_A_KEYBOARD];
+    int *mProximityCharsArray;
+    int mKeyXCoordinates[MAX_KEY_COUNT_IN_A_KEYBOARD];
+    int mKeyYCoordinates[MAX_KEY_COUNT_IN_A_KEYBOARD];
+    int mKeyWidths[MAX_KEY_COUNT_IN_A_KEYBOARD];
+    int mKeyHeights[MAX_KEY_COUNT_IN_A_KEYBOARD];
+    int mKeyCodePoints[MAX_KEY_COUNT_IN_A_KEYBOARD];
     float mSweetSpotCenterXs[MAX_KEY_COUNT_IN_A_KEYBOARD];
     float mSweetSpotCenterYs[MAX_KEY_COUNT_IN_A_KEYBOARD];
     float mSweetSpotRadii[MAX_KEY_COUNT_IN_A_KEYBOARD];