java.lang.IllegalStateException:

Unable to start activity ComponentInfo{com.cloudcreate.cloudcreateoffice/com.cloudcreate.cloudcreateoffice
.MainActivity}: java.lang.IllegalStateException: Only fullscreen activities can request orientation

// Activity不是透明且没有指定屏幕方向，默认设置为竖屏
if (getRequestedOrientation() == ActivityInfo.SCREEN_ORIENTATION_UNSPECIFIED) {
      setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
}

// 上边代码修改成:
if (Build.VERSION.SDK_INT == Build.VERSION_CODES.O && isTranslucentOrFloating()) {
            // android8.0要求不能设置全屏透明的Activity横竖屏
            fixOrientation();
} else {
            // 当前 Activity 不能是透明的并且没有指定屏幕方向，默认设置为竖屏
            if (getRequestedOrientation() == ActivityInfo.SCREEN_ORIENTATION_UNSPECIFIED) {
            setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
}
/**
 * 设置竖屏
 */
private boolean fixOrientation() {
      try {
            Field field = Activity.class.getDeclaredField("mActivityInfo");
            field.setAccessible(true);
            ActivityInfo o = (ActivityInfo) field.get(this);
            // 设置竖屏
            o.screenOrientation = 1;
            field.setAccessible(false);
            return true;
       } catch (Exception e) {
            e.printStackTrace();
       }
       return false;
}

/**
 * 是否是全屏或者悬浮
 */
private boolean isTranslucentOrFloating() {
      boolean isTranslucentOrFloating = false;
      try {
          int[] styleableRes = (int[]) Class.forName("com.android.internal.R$styleable").getField("Window").get(null);
          final TypedArray ta = obtainStyledAttributes(styleableRes);
          Method m = ActivityInfo.class.getMethod("isTranslucentOrFloating", TypedArray.class);
          m.setAccessible(true);
          isTranslucentOrFloating = (boolean) m.invoke(null, ta);
          m.setAccessible(false);
      } catch (Exception e) {
          e.printStackTrace();
      }
      return isTranslucentOrFloating;
}

/**
 * 设置方向的时候:直接不能设置
 */
@Override
public void setRequestedOrientation(int requestedOrientation) {
      if (Build.VERSION.SDK_INT == Build.VERSION_CODES.O && isTranslucentOrFloating()) {
           return;
      }
      super.setRequestedOrientation(requestedOrientation);
}

源地址: https://blog.csdn.net/starry_eve/article/details/82777160