Question

我正在尝试从片段xml获取ID，所以这是代码错误是 “无法解析方法findViewById”

在片段中是否可以使用findViewById？

public class Slide_Teacher_Add extends Fragment implements View.OnClickListener {

private EditText teacher_id_number;
private EditText teacher_fullname;
private EditText teacher_lesson;
private EditText teacher_contact;

private Button btn_add_teacher;

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

    View v = inflater.inflate(R.layout.activity_slide__teacher_add,container,false);
    return v;

    teacher_id_number = (EditText) findViewById(R.id.teacher_id_number);
    teacher_fullname = (EditText) findViewById(R.id.teacher_fullname);
    teacher_lesson = (EditText) findViewById(R.id.teacher_lesson);
    teacher_contact = (EditText) findViewById(R.id.teacher_contact);

    btn_add_teacher = (Button) findViewById(R.id.btn_add_teacher);


    btn_add_teacher.setOnClickListener(this);
}

Answer 1

在找到之前添加v。...像这样：

teacher_id_number = (EditText) v.findViewById(R.id.teacher_id_number);
teacher_fullname = (EditText) v.findViewById(R.id.teacher_fullname);
teacher_lesson = (EditText) v.findViewById(R.id.teacher_lesson);
teacher_contact = (EditText) v.findViewById(R.id.teacher_contact);

btn_add_teacher = (Button) v.findViewById(R.id.btn_add_teacher);

return v;

，您return v;就在里面。还需要将其移至底部。

Answer 2

您需要从膨胀的布局中获取View的参考。

    View v = inflater.inflate(R.layout.activity_slide__teacher_add,container,false);
    teacher_id_number = (EditText) v.findViewById(R.id.teacher_id_number);
    teacher_fullname = (EditText) v.findViewById(R.id.teacher_fullname);
    teacher_lesson = (EditText) v.findViewById(R.id.teacher_lesson);
    teacher_contact = (EditText) v.findViewById(R.id.teacher_contact);
    btn_add_teacher = (Button) v.findViewById(R.id.btn_add_teacher);
    return v;

Answer 3

首先，您在return语句后调用findViewById()，因此根本不会执行它们。接下来，您需要像在findViewById()中那样在视图的上下文中调用view.findViewById(int);，因此将代码重写为：

View v = inflater.inflate(R.layout.activity_slide__teacher_add,container,false);
teacher_id_number = v.findViewById(R.id.teacher_id_number); //Note this line
//other tasks you need to do
return v;

确保return是函数的最后一条语句。

Answer 4

无法到达return之后的代码，这是第一句话。接下来的findViewById()未定义到Fragment中，您必须从其父视图（即展开视图）中提取视图。因此，您的代码应如下所示：

 View v = inflater.inflate(R.layout.activity_slide__teacher_add,container,false);


    teacher_id_number = (EditText) v.findViewById(R.id.teacher_id_number);
    teacher_fullname = (EditText) v.findViewById(R.id.teacher_fullname);
    teacher_lesson = (EditText) v.findViewById(R.id.teacher_lesson);
    teacher_contact = (EditText) v.findViewById(R.id.teacher_contact);

    btn_add_teacher = (Button) v.findViewById(R.id.btn_add_teacher);


    btn_add_teacher.setOnClickListener(this);

   return v;

Answer 5

您可以使用onViewCreated功能，而无需查看Inflate。例如：

@Override
public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
    super.onViewCreated(view, savedInstanceState);

    view.findViewById(...);
    //....
}

或者您必须从findViewById对象类（v）中调用View函数。例如：

teacher_id_number = (EditText) v.findViewById(R.id.teacher_id_number);

无法解析片段中的findViewById

5 个答案: