chore: prevent memory leaks in Iap.java by using WeakReference for Context and Activity references

I used the Weak Reference passing the Context and Activity instead of the old Context and Activity directly, this is done to prevent memory leaks and unexpected closure if the context or activity become null

Author: ThDev-only

src/plugins/iap/src/com/foxdebug/iap/Iap.java

@@ -23,6 +23,7 @@
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
+import java.lang.ref.WeakReference;
 import org.apache.cordova.CallbackContext;
 import org.apache.cordova.CordovaInterface;
 import org.apache.cordova.CordovaPlugin;
@@ -35,14 +36,14 @@
 public class Iap extends CordovaPlugin {
 
   private BillingClient billingClient;
-  private Context context;
-  private Activity activity;
+  private WeakReference<Context> contextRef;
+  private WeakReference<Activity> activityRef;
   private CallbackContext purchaseUpdated;
 
   public void initialize(CordovaInterface cordova, CordovaWebView webView) {
     super.initialize(cordova, webView);
-    context = cordova.getContext();
-    activity = cordova.getActivity();
+    contextRef = new WeakReference<>(cordova.getContext());
+    activityRef = new WeakReference<>(cordova.getActivity());
     billingClient = getBillingClient();
   }
 
@@ -103,7 +104,7 @@ public void run() {
 
   private BillingClient getBillingClient() {
     return BillingClient
-      .newBuilder(this.context)
+      .newBuilder(this.contextRef.get())
       .enablePendingPurchases()
       .setListener(
         new PurchasesUpdatedListener() {
@@ -248,7 +249,7 @@ private void purchase(String json, CallbackContext callbackContext) {
     try {
       SkuDetails skuDetails = new SkuDetails(json);
       BillingResult result = billingClient.launchBillingFlow(
-        activity,
+        activityRef.get(),
         BillingFlowParams.newBuilder().setSkuDetails(skuDetails).build()
       );
       int responseCode = result.getResponseCode();