如何在Fragment中设置TextView的值? [英] How to set value of a TextView in Fragment?

问题描述

我在动态应用程序中使用片段，其中User.java文件包含值，而 TabbedActivity.java 文件包含三个片段.我想将文本设置为 ProfileFrgament.java 中的 TextView .因此，我在 fragment_profile.xml 中创建了一个 TextView ，并使用以下代码

I am using fragments in my dynamic application, where the User.java file contains the values and TabbedActivity.java file contains three fragments. I want to set the text to TextView in ProfileFrgament.java. So, I created a TextView in fragment_profile.xml and referenced it from TabbedActivity.java file with the following code

    name = findViewById(R.id.name);
    //getting the current user
    User user = SharedPrefManager.getInstance(this).getUser();
    //setting values to textviews
    name.setText(user.getUsername());

它没有显示任何编译错误，但是在打开 TabbedActivity.java 之后，应用程序在行 name.setText(user.getUsername()); 处以NullPointerException停止如何解决这个问题?

It does not shows any compilation error, but after opening TabbedActivity.java, the app stops with NullPointerException at line name.setText(user.getUsername()); How to solve this issue?

这是 ProfileFragment.java 文件的代码

 public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, Bundle savedInstanceState) {

    name = getActivity().findViewById(R.id.name);
    //getting the current user
    User user = SharedPrefManager.getInstance(getActivity()).getUser();
    //setting values to textviews
    name.setText(user.getUsername());

    return inflater.inflate(R.layout.fragment_profile, container, false);
}

推荐答案

您的 TextView 位于 fragment_profile.xml 中，而您试图找到该 TextView TabbedActivity.java 中的code>，因此发生了 NullPointerException

Your TextView is in fragment_profile.xml and you trying to find that TextView in TabbedActivity.java, so NullPointerException is occured

将此代码放在 ProfileFrgament.java

通过此代码更改代码

public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, Bundle savedInstanceState) 
{ 
    final View rootView = inflater.inflate(R.layout.fragment_profile, container, false);
    name = (TextView) rootView.findViewById(R.id.name);
    User user = SharedPrefManager.getInstance(getActivity()).getUser(); 
    name.setText(user.getUsername()); 

    return rootView;
}

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