IllegalStateException:片段已添加；无法从结构日志中确定确切原因和位置

FragmentManager fragmentManager = getSupportFragmentManager();
Fragment existingFragment = fragmentManager.findFragmentByTag("myFragmentTag");

if (existingFragment == null) {
    // 片段不存在，可以安全地添加
    FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
    fragmentTransaction.add(R.id.fragment_container, new MyFragment(), "myFragmentTag");
    fragmentTransaction.commit();
} else {
    // 片段已经存在，可以选择不再添加或者先移除再重新添加
    // fragmentTransaction.remove(existingFragment);
    // fragmentTransaction.add(R.id.fragment_container, existingFragment, "myFragmentTag");
    // fragmentTransaction.commit();
}