问题来源

Android8.0中Activity如果设置了样式透明，就不能指定Activity的方向。坑坑坑

解决办法

1）删除

android:screenOrientation="portrait" 

来自minifyst.xml

2）在活动上添加这两行

 protected void onCreate(Bundle savedInstanceState) {
     setOrientation(this)
     super.onCreate(savedInstanceState);
     // other other all code here

 }

3）只需将代码复制粘贴到您的活动中

 public static void setOrientation(Activity context) {
          if (android.os.Build.VERSION.SDK_INT == Build.VERSION_CODES.O)
              context.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_UNSPECIFIED);
          else
              context.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
    }