想照著音量對話框的做法，作一個在後台顯示Dialog的方法，可是在Dialog.show()的時候，出了下面這個異樣：
Android.view.WindowManager$BadTokenException: Unable to add window android.view.ViewRootImpl$W@411da608 -- permission denied for this window type:
at android.view.ViewRootImpl.setView(ViewRootImpl.java:537)
at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:301)
at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:215)
at android.view.WindowManagerImpl$CompatModeWrapper.addView(WindowManagerImpl.java:140)
at android.view.Window$LocalWindowManager.addView(Window.java:537)
at android.app.Dialog.show(Dialog.java:278)
1、異常原因-沒加權限
往下的調用順序是
① android.view.ViewRootImpl.setView(ViewRootImpl.java:481)
② com.android.server.wm.Session.add(Session.java:139)
③ com.android.server.wm.WindowManagerService.addWindow(WindowManagerService:1999)
④ com.android.internal.policy.impl.PhoneWindowManager.checkAddPermission(PhoneWindowMana:1063)
在這裡發現了
String permission = null;
switch (type) {
case TYPE_TOAST:
// XXX right now the app process has complete control over
// this... should introduce a token to let the system
// monitor/control what they are doing.
break;
case TYPE_INPUT_METHOD:
case TYPE_WALLPAPER:
// The window manager will check these.
break;
case TYPE_PHONE:
case TYPE_PRIORITY_PHONE:
case TYPE_SYSTEM_ALERT:
case TYPE_SYSTEM_ERROR:
case TYPE_SYSTEM_OVERLAY:
permission = android.Manifest.permission.SYSTEM_ALERT_WINDOW;
break;
default:
permission = android.Manifest.permission.INTERNAL_SYSTEM_WINDOW;
}
音量對話框用的是“TYPE_VOLUME_OVERLAY”，那就加上“INTERNAL_SYSTEM_WINDOW”
可是帶進去一跑，還是不行，再找