Android Fragment忘记按钮

Question

我的片段初始化按钮，我可以在调试器中看到它。 当我从布局中包含片段的活动中调用 setButtonText 方法时，按钮变为空。我在网上查过，但到目前为止我没有找到任何解决方案

public class PrepareTrainingFragment extends Fragment
{
private Button button;
private TextView tv;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState)
{
    View v = inflater.inflate(R.layout.preparetrainingfragment, container, false);
    button=(Button) v.findViewById(R.id.ptfragmentbtn);
    Log.w("button init","button init");
    return v;
}

public void setButtonText(String text)
{
    button.setText(text);
}

在封装片段的类中：

@Override
protected void onCreate(Bundle savedInstanceState) 
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
//  getWindow().getDecorView().setSystemUiVisibility(View.SYSTEM_UI_FLAG_HIDE_NAVIGATION); //hide navigation bar temporarily


    driverFragment=new PrepareTrainingFragment();


    FragmentManager fragmentManager = getFragmentManager();
    FragmentTransaction fragmentTransaction = 
    fragmentManager.beginTransaction();

    fragmentTransaction.replace(android.R.id.content, driverFragment);

    driverFragment.setButtonText("hello");


}       

Answer 1

FragmentTransaction 不是实时执行的，你必须调用 boolean result = fragmentTransaction.executePendingTransactions();在更新您的按钮之前。另外，为什么不更新 Fragment 中的按钮？