Exception android.view.WindowManager$BadTokenException: Unable to add window — token android.os.BinderProxy@419abb98 is not valid; is your activity running?

Exception android.view.WindowManager$BadTokenException: Unable to add window — token android.os.BinderProxy@419abb98 is not valid; is your activity running?

android.view.ViewRootImpl.setView (ViewRootImpl.java:720)

android.view.WindowManagerImpl.addView (WindowManagerImpl.java:356)

android.view.WindowManagerImpl.addView (WindowManagerImpl.java:234)

android.view.WindowManagerImpl$CompatModeWrapper.addView (WindowManagerImpl.java:153)

android.view.Window$LocalWindowManager.addView (Window.java:559)

android.app.ActivityThread.handleResumeActivity (ActivityThread.java:2716)

android.app.ActivityThread.handleLaunchActivity (ActivityThread.java:2151)

android.app.ActivityThread.access$700 (ActivityThread.java:140)

android.app.ActivityThread$H.handleMessage (ActivityThread.java:1238)

android.os.Handler.dispatchMessage (Handler.java:99)

android.os.Looper.loop (Looper.java:177)

android.app.ActivityThread.main (ActivityThread.java:4947)

java.lang.reflect.Method.invokeNative (Method.java)

java.lang.reflect.Method.invoke (Method.java:511)

com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run (ZygoteInit.java:1038)

com.android.internal.os.ZygoteInit.main (ZygoteInit.java:805)

dalvik.system.NativeStart.main (NativeStart.java)

■ BadTokenException의 원인 ■

이미 종료된 Activity의 context를 인자로 다이얼로그 창을 표시하려고 할 때 발생. 

다이얼로그 창을 표시할 Activity가 없기 때문에 안드로이드 런타임이 BadTokenException이라는 예외를 발생시킨다.

■ 해결법 ■

isFinishing() 메소드를 사용하여 Activity의 종료 여부를 확인 후 처리한다.

■ 샘플 코드 ■

if(!MainActivity.this.isFinishing()) {

    AlertDialog.builder dialog  = new AlertDialog.builder(MainActivity.this);

    dialog.setTitle(“알림”);

    dialog.setMessage(“테스트 메세지”);

    dialog.show();

}