use AndroidX

android/build.gradle

@@ -5,12 +5,11 @@ def safeExtGet(prop, fallback) {
 }
 
 android {
-    compileSdkVersion safeExtGet("compileSdkVersion", 25)
-    buildToolsVersion safeExtGet("buildToolsVersion", '25.0.2')
+    compileSdkVersion safeExtGet("compileSdkVersion", 28)
 
     defaultConfig {
         minSdkVersion safeExtGet('minSdkVersion', 16)
-        targetSdkVersion safeExtGet('targetSdkVersion', 25)
+        targetSdkVersion safeExtGet('targetSdkVersion', 28)
         versionCode 1
         versionName "1.0"
     }

android/lib/src/main/java/com/swmansion/gesturehandler/GestureHandlerOrchestrator.java

@@ -11,7 +11,7 @@
 import java.util.Arrays;
 import java.util.Comparator;
 
-import javax.annotation.Nullable;
+import androidx.annotation.Nullable;
 
 public class GestureHandlerOrchestrator {
 

android/src/main/java/com/swmansion/gesturehandler/react/RNGestureHandlerEnabledRootView.java

@@ -7,7 +7,7 @@
 import com.facebook.react.ReactInstanceManager;
 import com.facebook.react.ReactRootView;
 
-import javax.annotation.Nullable;
+import androidx.annotation.Nullable;
 
 public class RNGestureHandlerEnabledRootView extends ReactRootView {
 

android/src/main/java/com/swmansion/gesturehandler/react/RNGestureHandlerEvent.java

@@ -1,14 +1,14 @@
 package com.swmansion.gesturehandler.react;
 
-import android.support.v4.util.Pools;
+import androidx.core.util.Pools;
 
 import com.facebook.react.bridge.Arguments;
 import com.facebook.react.bridge.WritableMap;
 import com.facebook.react.uimanager.events.Event;
 import com.facebook.react.uimanager.events.RCTEventEmitter;
 import com.swmansion.gesturehandler.GestureHandler;
 
-import javax.annotation.Nullable;
+import androidx.annotation.Nullable;
 
 public class RNGestureHandlerEvent extends Event<RNGestureHandlerEvent> {
 

android/src/main/java/com/swmansion/gesturehandler/react/RNGestureHandlerModule.java

@@ -33,7 +33,7 @@
 import java.util.List;
 import java.util.Map;
 
-import javax.annotation.Nullable;
+import androidx.annotation.Nullable;
 
 import static com.swmansion.gesturehandler.GestureHandler.HIT_SLOP_NONE;
 

android/src/main/java/com/swmansion/gesturehandler/react/RNGestureHandlerPackage.java

@@ -13,7 +13,7 @@
 import java.util.List;
 import java.util.Map;
 
-import javax.annotation.Nullable;
+import androidx.annotation.Nullable;
 
 public class RNGestureHandlerPackage implements ReactPackage {
 

android/src/main/java/com/swmansion/gesturehandler/react/RNGestureHandlerRegistry.java

@@ -8,7 +8,7 @@
 
 import java.util.ArrayList;
 
-import javax.annotation.Nullable;
+import androidx.annotation.Nullable;
 
 public class RNGestureHandlerRegistry implements GestureHandlerRegistry {
 

android/src/main/java/com/swmansion/gesturehandler/react/RNGestureHandlerRootInterface.java

@@ -1,6 +1,6 @@
 package com.swmansion.gesturehandler.react;
 
-import javax.annotation.Nullable;
+import androidx.annotation.Nullable;
 
 public interface RNGestureHandlerRootInterface {
   @Nullable RNGestureHandlerRootHelper getRootHelper();

android/src/main/java/com/swmansion/gesturehandler/react/RNGestureHandlerRootView.java

@@ -7,7 +7,7 @@
 import com.facebook.react.bridge.ReactContext;
 import com.facebook.react.views.view.ReactViewGroup;
 
-import javax.annotation.Nullable;
+import androidx.annotation.Nullable;
 
 public class RNGestureHandlerRootView extends ReactViewGroup {
 

android/src/main/java/com/swmansion/gesturehandler/react/RNGestureHandlerRootViewManager.java

@@ -7,7 +7,7 @@
 
 import java.util.Map;
 
-import javax.annotation.Nullable;
+import androidx.annotation.Nullable;
 
 /**
  * React native's view manager used for creating instances of {@link }RNGestureHandlerRootView}. It

android/src/main/java/com/swmansion/gesturehandler/react/RNGestureHandlerStateChangeEvent.java

@@ -1,14 +1,14 @@
 package com.swmansion.gesturehandler.react;
 
-import android.support.v4.util.Pools;
+import androidx.core.util.Pools;
 
 import com.facebook.react.bridge.Arguments;
 import com.facebook.react.bridge.WritableMap;
 import com.facebook.react.uimanager.events.Event;
 import com.facebook.react.uimanager.events.RCTEventEmitter;
 import com.swmansion.gesturehandler.GestureHandler;
 
-import javax.annotation.Nullable;
+import androidx.annotation.Nullable;
 
 public class RNGestureHandlerStateChangeEvent extends Event<RNGestureHandlerStateChangeEvent>{