Question

我是Android新手，这是我的第一个项目！当我将它用作活动时，此代码正在运行但是当我添加为片段时，它会显示如下错误：

错误：（30,27）错误：找不到符号方法findViewById（int）错误：（43,44）错误：不兼容的类型：calender_fragment不能转换为上下文。

请帮我解决这个问题，这是我的calender_fragment.java

public class calender_fragment extends Fragment {
View myView;
EditText date;
DatePickerDialog datePickerDialog;

@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, Bundle savedInstanceState) {
    myView = inflater.inflate(R.layout.calender_layout, container, false);


    // initiate the date picker and a button
    date = (EditText) findViewById(R.id.date);
    return myView;
    // perform click event on edit text
    date.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            // calender class's instance and get current date , month and year from calender
            final Calendar c = Calendar.getInstance();
            int mYear = c.get(Calendar.YEAR); // current year
            int mMonth = c.get(Calendar.MONTH); // current month
            int mDay = c.get(Calendar.DAY_OF_MONTH); // current day

            // date picker dialog
            datePickerDialog = new DatePickerDialog(calender_fragment.this,
                    new DatePickerDialog.OnDateSetListener() {

                        @Override
                        public void onDateSet(DatePicker view, int year,
                                              int monthOfYear, int dayOfMonth) {
                            // set day of month , month and year value in the edit text
                            date.setText(dayOfMonth + "/"
                                    + (monthOfYear + 1) + "/" + year);

                        }
                    }, mYear, mMonth, mDay);
            datePickerDialog.show();
        }
    });

}

}

这是我的calender_layout.xml：

 <EditText
    android:id="@+id/date"
    android:layout_width="200dp"
    android:layout_height="wrap_content"
    android:layout_centerHorizontal="true"
    android:layout_marginBottom="8dp"
    android:layout_marginEnd="8dp"
    android:layout_marginStart="8dp"
    android:layout_marginTop="8dp"
    android:background="#d4d4d4"
    android:hint="Select Date..."
    android:padding="15dp"
    android:textColor="#897"
    android:textColorHint="#090"
    android:textSize="20sp"
    android:textStyle="bold"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintHorizontal_bias="0.279"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    app:layout_constraintVertical_bias="0.294" />

<TextView
    android:id="@+id/textView"
    android:layout_width="206dp"
    android:layout_height="61dp"
    android:layout_marginBottom="8dp"
    android:layout_marginEnd="8dp"
    android:layout_marginStart="8dp"
    android:layout_marginTop="8dp"
    android:text="Select the Date of Draw: "
    android:textSize="24sp"
    android:textStyle="normal|bold"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintHorizontal_bias="0.29"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    app:layout_constraintVertical_bias="0.131" />

<Button
    android:id="@+id/button"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginBottom="8dp"
    android:layout_marginEnd="8dp"
    android:layout_marginStart="8dp"
    android:layout_marginTop="8dp"
    android:text="GO"
    android:textSize="18sp"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintHorizontal_bias="0.778"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    app:layout_constraintVertical_bias="0.498" />

Answer 1

您应该从片段
中充气的视图中findViewById()
date = (EditText) myView.findViewById(R.id.date);
并将活动上下文传递给对话框构造函数

datePickerDialog = new DatePickerDialog(getActivity(),
然后将return myView;移至onCreateView()的最后一个

完整代码：

public class calender_fragment extends Fragment { 
View myView;
EditText date;
DatePickerDialog datePickerDialog;

@Nullable 
@Override 
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, Bundle savedInstanceState) {
    myView = inflater.inflate(R.layout.calender_layout, container, false);


    // initiate the date picker and a button 
    date = (EditText) myView.findViewById(R.id.date); /** <-- use View.findViewById() in Fragment */

    // perform click event on edit text 
    date.setOnClickListener(new View.OnClickListener() {
        @Override 
        public void onClick(View v) {
            // calender class's instance and get current date , month and year from calender 
            final Calendar c = Calendar.getInstance();
            int mYear = c.get(Calendar.YEAR); // current year
            int mMonth = c.get(Calendar.MONTH); // current month
            int mDay = c.get(Calendar.DAY_OF_MONTH); // current day

            // date picker dialog 
            datePickerDialog = new DatePickerDialog(getActivity(),  /* <-- use getActivity() */
                    new DatePickerDialog.OnDateSetListener() {

                        @Override 
                        public void onDateSet(DatePicker view, int year,
                                              int monthOfYear, int dayOfMonth) {
                            // set day of month , month and year value in the edit text 
                            date.setText(dayOfMonth + "/"
                                    + (monthOfYear + 1) + "/" + year);

                        } 
                    }, mYear, mMonth, mDay);
            datePickerDialog.show();
        } 
    }); 

    return myView;  /* <--- move the "return" here */
}

calender_fragment无法转换为上下文，找不到方法findViewById（int）

1 个答案: