Activity中异步操作showDialog异常解决方法：判断Ay是否结束

Android – Displaying Dialogs From Background Threads

判断一下Activity是否在finishing就好了，否则万一Activity销毁了，这个Dialog没有所依附的对象，就会有下面的异常抛出

private Handler myHandler = new Handler() {
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case DISPLAY_DLG:
if (!isFinishing()) {
showDialog(MY_DIALOG);
}
break;
}
}
};

android.view.WindowManager$BadTokenException: Unable to add window — token android.os.BinderProxy@447a6748 is not valid; is your activity running?
at android.view.ViewRoot.setView(ViewRoot.java:468)
at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:177)
at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:91)
at android.view.Window$LocalWindowManager.addView(Window.java:424)
at android.app.Dialog.show(Dialog.java:239)
at android.app.Activity.showDialog(Activity.java:2488)
…
at android.os.Handler.dispatchMessage(Handler.java:99)
…