Added onPause callback for Android

Author: aksh1t

android/src/main/java/com/pspdfkit/flutter/pspdfkit/FlutterPdfActivity.java

@@ -9,6 +9,8 @@
 
 import java.util.concurrent.atomic.AtomicReference;
 
+import io.flutter.plugin.common.MethodChannel;
+import io.flutter.plugin.common.MethodChannel.MethodCallHandler;
 import io.flutter.plugin.common.MethodChannel.Result;
 
 /**
@@ -18,18 +20,29 @@
 public class FlutterPdfActivity extends PdfActivity {
 
     private static FlutterPdfActivity currentActivity;
+    private static MethodChannel channel;
     private static AtomicReference<Result> loadedDocumentResult = new AtomicReference<>();
 
     public static void setLoadedDocumentResult(Result result) {
         loadedDocumentResult.set(result);
     }
 
+    public static void setMethodChannel(MethodChannel methodChannel) {
+        channel = methodChannel;
+    }
+
     @Override
     protected void onCreate(Bundle bundle) {
         super.onCreate(bundle);
         bindActivity();
     }
 
+    @Override
+    protected void onPause() {
+        super.onPause();
+        channel.invokeMethod("flutterPdfActivityOnPause", null, null);
+    }
+
     @Override
     protected void onDestroy() {
         super.onDestroy();

android/src/main/java/com/pspdfkit/flutter/pspdfkit/PspdfkitPlugin.java

@@ -63,6 +63,7 @@ public class PspdfkitPlugin implements MethodCallHandler, PluginRegistry.Request
     private static final String FILE_SCHEME = "file:///";
     private final Context context;
     private final Registrar registrar;
+    private static MethodChannel channel;
     /** Atomic reference that prevents sending twice the permission result and throwing exception. */
     private AtomicReference<Result> permissionRequestResult;
 
@@ -76,7 +77,7 @@ private PspdfkitPlugin(Registrar registrar) {
      * Plugin registration.
      */
     public static void registerWith(Registrar registrar) {
-        final MethodChannel channel = new MethodChannel(registrar.messenger(), "pspdfkit");
+        channel = new MethodChannel(registrar.messenger(), "pspdfkit");
         PspdfkitPlugin pspdfkitPlugin = new PspdfkitPlugin(registrar);
         channel.setMethodCallHandler(pspdfkitPlugin);
         registrar.addRequestPermissionsResultListener(pspdfkitPlugin);
@@ -88,6 +89,8 @@ public void onMethodCall(@NonNull MethodCall call, @NonNull Result result) {
         FlutterPdfActivity flutterPdfActivity;
         PdfDocument document;
 
+        FlutterPdfActivity.setMethodChannel(channel);
+
         switch (call.method) {
             case "frameworkVersion":
                 result.success("Android " + PSPDFKit.VERSION);

example/lib/main.dart

@@ -268,6 +268,10 @@ class _HomePageState extends State<HomePage> with WidgetsBindingObserver {
     Pspdfkit.setLicenseKey("LICENSE_KEY_GOES_HERE");
   }
 
+  void flutterPdfActivityOnPauseHandler() {
+    print("flutterPdfActivityOnPauseHandler");
+  }
+
   void pdfViewControllerWillDismissHandler() {
     print("pdfViewControllerWillDismissHandler");
   }
@@ -279,6 +283,7 @@ class _HomePageState extends State<HomePage> with WidgetsBindingObserver {
   @override
   Widget build(BuildContext context) {
     Pspdfkit.setupPlatformCallHandler();
+    Pspdfkit.flutterPdfActivityOnPause = () => flutterPdfActivityOnPauseHandler();
     Pspdfkit.pdfViewControllerWillDismiss = () => pdfViewControllerWillDismissHandler();
     Pspdfkit.pdfViewControllerDidDismiss = () => pdfViewControllerDidDismissHandler();
 

lib/pspdfkit.dart

@@ -95,12 +95,16 @@ class Pspdfkit {
     }
   }
 
+  static VoidCallback flutterPdfActivityOnPause;
   static VoidCallback pdfViewControllerWillDismiss;
   static VoidCallback pdfViewControllerDidDismiss;
 
   static Future<void> _platformCallHandler(MethodCall call) {
     try {
       switch (call.method) {
+        case 'flutterPdfActivityOnPause':
+          flutterPdfActivityOnPause();
+          break;
         case 'pdfViewControllerWillDismiss':
           pdfViewControllerWillDismiss();
           break;