通过接口发送后无法访问的 ArrayList 项

Question

问题是我无法从ArrayList<Integer> 中检索Integer 值，该值是从TimePickerFragment 通过接口发送到FragmentActivity。当我尝试获取保存的值时（请参阅下面的 FragmentActivity），我得到“不兼容的类型。必需：java.lang.Integer，找到：java.lang.Object”。

时间选择器片段：

public class TimePickerFragment extends DialogFragment
    implements TimePickerDialog.OnTimeSetListener {

Listener mListener;

// declaration of the interface
public interface Listener {
    public void onUserTimeChoice(ArrayList dataSet);
}


// registration of the listener
public void registerListener(Listener listener) {
    mListener = listener;
}


@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
    // Use the current time as the default values for the picker
    final Calendar c = Calendar.getInstance();
    int hour = c.get(Calendar.HOUR_OF_DAY);
    int minute = c.get(Calendar.MINUTE);

    // Create a new instance of TimePickerDialog and return it
    return new TimePickerDialog(getActivity(), this, hour, minute,
            DateFormat.is24HourFormat(getActivity()));
}

public void onTimeSet(TimePicker view, int hourOfDay, int minute) {
    // Do something with the time chosen by the user
    ArrayList<Integer> mAList = new ArrayList();

    mAList.add(hourOfDay);
    mAList.add(minute);
    mListener.onUserTimeChoice(mAList);
}
}

FragmentActivity（摘录）：

@Override
public void onUserTimeChoice(ArrayList dataSet) {

    Integer hour = dataSet.get(0);   //  <--- incompatible types
    Integer minute = dataSet.get(1); // <--- incompatible types

}

Answer 1

在dataSet 中使用泛型类型而不是raw type。 ArrayList dataSet 等价于ArrayList<Object> dataSet

使用List而不是ArrayList向接口添加代码

public void onUserTimeChoice(List<Integer> dataSet) {