Fix application exit null-pointer exception (flutter-webrtc#582)

pan1nx · web-flow · commit cbff1e7c4440 · 2021-06-07T17:08:08.000+08:00
When application exits, it throws an exception: Exception 'java.lang.NullPointerException' occurred in thread 'main' at com.cloudwebrtc.webrtc.FlutterWebRTCPlugin.onDetachedFromActivity(FlutterWebRTCPlugin.java:97) See also issue flutter-webrtc#578 Signed-off-by: Peter Antoniac <pan1nx+flutterwebrtc@gmail.com>
diff --git a/android/src/main/java/com/cloudwebrtc/webrtc/FlutterWebRTCPlugin.java b/android/src/main/java/com/cloudwebrtc/webrtc/FlutterWebRTCPlugin.java
@@ -94,7 +94,9 @@ public void onDetachedFromActivity() {
         methodCallHandler.setActivity(null);
         if (this.observer != null) {
             this.lifecycle.removeObserver(this.observer);
-            this.application.unregisterActivityLifecycleCallbacks(this.observer);
+            if (this.application!=null) {
+                this.application.unregisterActivityLifecycleCallbacks(this.observer);
+            }
         }
         this.lifecycle = null;
     }

Original file line number	Diff line number	Diff line change
`@@ -94,7 +94,9 @@ public void onDetachedFromActivity() {`
`94`	`94`	`methodCallHandler.setActivity(null);`
`95`	`95`	`if (this.observer != null) {`
`96`	`96`	`this.lifecycle.removeObserver(this.observer);`
`97`		`- this.application.unregisterActivityLifecycleCallbacks(this.observer);`
	`97`	`+ if (this.application!=null) {`
	`98`	`+ this.application.unregisterActivityLifecycleCallbacks(this.observer);`
	`99`	`+ }`
`98`	`100`	`}`
`99`	`101`	`this.lifecycle = null;`
`100`	`102`	`}`