我使用下面的代码在android8.1手机上检索android锁屏壁纸:WallpaperManagermanager=WallpaperManager.getInstance(getActivity());ParcelFileDescriptorpfd=manager.getWallpaperFile(WallpaperManager.FLAG_LOCK);if(pfd==null)//pfdisalwaysnullforFLAG_LOCK,why?return;BitmaplockScreenWallpaper=BitmapFactory.decodeFileDescriptor(