Android如何获取系统通知的开启状态详解

public class NotificationsUtils {
 private static final String CHECK_OP_NO_THROW = "checkOpNoThrow";
 private static final String OP_POST_NOTIFICATION = "OP_POST_NOTIFICATION";
 public static boolean isNotificationEnabled(Context context) {
  AppOpsManager mAppOps = (AppOpsManager)
  context.getSystemService(Context.APP_OPS_SERVICE);
  ApplicationInfo appInfo = context.getApplicationInfo();
  String pkg = context.getApplicationContext().getPackageName();
  int uid = appInfo.uid;
  Class appOpsClass = null; /* Context.APP_OPS_MANAGER */
  try {
   appOpsClass = Class.forName(AppOpsManager.class.getName());
   Method checkOpNoThrowMethod = appOpsClass.getMethod(CHECK_OP_NO_THROW, Integer.TYPE, Integer.TYPE, String.class);
   Field opPostNotificationValue = appOpsClass.getDeclaredField(OP_POST_NOTIFICATION);
   int value = (int)opPostNotificationValue.get(Integer.class);
   return ((int)checkOpNoThrowMethod.invoke(mAppOps,value, uid, pkg) == AppOpsManager.MODE_ALLOWED);
  }
  catch (ClassNotFoundException e) {
   e.printStackTrace();
  } catch (NoSuchMethodException e) {
   e.printStackTrace();
  } catch (NoSuchFieldException e) {
   e.printStackTrace();
  } catch (InvocationTargetException e) {
   e.printStackTrace();
  } catch (IllegalAccessException e) {
   e.printStackTrace();
  }
  return false;
 }
}