尝试打开对话框时出现以下Android异常。有人可以帮我了解发生了什么,如何解决此问题?
android.view.WindowManager$BadTokenException:
Unable to add window -- token null is not for an application
at android.view.ViewRoot.setView(ViewRoot.java:509)
at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:177)
at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:91)
at android.app.Dialog.show(Dialog.java:241)