调用Fragment时Activity被销毁

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    if (savedInstanceState == null) {
        // 创建并添加Fragment
        Fragment fragment = new MyFragment();
        getSupportFragmentManager().beginTransaction()
                .add(R.id.fragment_container, fragment)
                .commit();
    }
}

@Override
public void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);
    // 保存Fragment的状态和数据
    outState.putString("key", value);
}

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    if (savedInstanceState != null) {
        // 恢复Fragment的状态和数据
        value = savedInstanceState.getString("key");
    }
}