Android:无法在 fragment 中设置 TextView 值

Question

所以我今天开始使用 fragment ，我试图在 fragment 打开时设置 TextView 值。值可以更改，所以我将它们全部打包到 1 个函数中，以便可以调用它来更新数据。这里:

public void loadDetails(){
    ShortcutFunc sf = new ShortcutFunc(this.getActivity());
    ConversePrefs cp = new ConversePrefs(this.getActivity());
    sf.setTextValue(getActivity(), R.id.profile_name, cp.GetStringSetting("name", "unset") + " " + cp.GetStringSetting("surname", "unset"));
    String dob = cp.GetStringSetting("dob", "unset");
    String bod[] = dob.split("\\-");

    LocalDate birthdate = new LocalDate (Integer.valueOf(bod[2]), Integer.valueOf(bod[1]), Integer.valueOf(bod[0]));
    LocalDate now = new LocalDate();
    Years age = Years.yearsBetween(birthdate, now);
    sf.setTextValue(getActivity(), R.id.profile_bd, dob + " (" + String.valueOf(age) + ")");
    sf.setTextValue(this.getActivity(), R.id.profile_country, cp.GetStringSetting("country", "unset").toString());
    sf.setTextValue(this.getActivity(), R.id.profile_email, cp.GetStringSetting("email", "unset").toString());

    String joined[] = cp.GetStringSetting("join", "unset").split("\\s+");
    String joinedArray[] = joined[0].split("\\-");

    LocalDate joindate = new LocalDate(Integer.valueOf(joinedArray[0]), Integer.valueOf(joinedArray[1]), Integer.valueOf(joinedArray[2]));
    LocalDate today = new LocalDate();
    //Years joinedThen = Years.yearsBetween(joindate, today);
    Days joinedThen = Days.daysBetween(joindate, today);

    sf.setTextValue(this.getActivity(), R.id.profile_join, joined[0] + " (" + joinedThen.toString() + " Days)");
    sf.setTextValue(this.getActivity(), R.id.profile_user, cp.GetStringSetting("username", "unset").toString());
}

ShortcutFunc 包含这个函数:

public void setTextValue(Activity act, int id, String text){
    TextView tv = (TextView)act.findViewById(id);
    tv.setText(text);
}

我用它来节省时间和设置 TextViews 而无需做所有声明等。我在 ShortcutFunc 函数的 tv.setText(text) 上得到 NullPointerException。

这就是我调用 loadDetails() 的方式:

@Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        loadDetails();
    }

怎么了？

Answer 1

这些 TextView 是您的 Fragment 的成员，而不是持有 Fragment 的 Activity 的成员。您应该从您在OnCreateView() 方法

中为您的 fragment 膨胀的 View 初始化它们

public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        View view = inflater.inflate(R.layout.my_view, container, false);
        textView = (TextView) view.findViewById(R.id.my_text_view);
        return view;
}