第一种方法 

public static void avoidSpinnerDropdownFocus(Spinner spinner) {
    try {
        Field listPopupField = Spinner.class.getDeclaredField("mPopup");
        listPopupField.setAccessible(true);
        Object listPopup = listPopupField.get(spinner);
        if (listPopup instanceof ListPopupWindow) {
            Field popupField = ListPopupWindow.class.getDeclaredField("mPopup");
            popupField.setAccessible(true);
            Object popup = popupField.get((ListPopupWindow) listPopup);
            if (popup instanceof PopupWindow) {
                ((PopupWindow) popup).setFocusable(false);
            }
        }
    } catch (NoSuchFieldException e) {
        e.printStackTrace();
    } catch (IllegalAccessException e) {
        e.printStackTrace();
    }
}

第二种方法

@Override
public void onWindowFocusChanged(boolean hasFocus) {
    super.onWindowFocusChanged(hasFocus);
    if (hasFocus) {
    getWindow().getDecorView().setSystemUiVisibility(
    View.SYSTEM_UI_FLAG_LAYOUT_STABLE | View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
        | View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN | View.SYSTEM_UI_FLAG_HIDE_NAVIGATION
        | View.SYSTEM_UI_FLAG_FULLSCREEN | View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY);
    }
}

第三种方法

private void fullScreenImmersive(View view) {
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
      int uiOptions = View.SYSTEM_UI_FLAG_LAYOUT_STABLE
        | View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
        | View.SYSTEM_UI_FLAG_HIDE_NAVIGATION
        | View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY
        | View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
        | View.SYSTEM_UI_FLAG_FULLSCREEN;
      view.setSystemUiVisibility(uiOptions);
    }
  }
 
  @Override
  public void show() {
    this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE, WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE);
    super.show();
    fullScreenImmersive(getWindow().getDecorView());
    this.getWindow().clearFlags(WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE);
  }

将spinner控件传进去就可以了