java - 在 Activity 中为 DialogFragment 设置监听器

Question

我正在尝试在我的 DialogFragment 上的 Activity 中实现一个监听器(它有 3 个 numberPicker 小部件元素)，该监听器将用于在 Activity 的 textView 中设置值，并且我不想将此 Fragment 类设置为内部类Activity 并在“确定”按钮的 OnClickListener 中设置 TextView ，因为在这种情况下我必须使 View 静态，这是不可取的。我知道 NumberPicker 类有一个 onValueChange 监听器，但是如何设置一个从 3 个选择器元素获取值的监听器。任何在 Activity 中实现此类监听器的帮助将不胜感激。

 public class PickerDialog extends DialogFragment {
        NumberPicker numberPicker;
        NumberPicker numberPicker2;
        NumberPicker numberPicker3;
        public static PickerDialog newInstance() {
            PickerDialog frag = new PickerDialog ();
            return frag;
        }


        @Override
        public Dialog onCreateDialog(Bundle savedInstanceState) {
            View child = getActivity().getLayoutInflater().inflate(R.layout.dialog, null);
             numberPicker = child.findViewById(R.id.numberPicker1);
              numberPicker2 = child.findViewById(R.id.numberPicker2);
               numberPicker3 = child.findViewById(R.id.numberPicker3);

            numberPicker.setMinValue(0);
            numberPicker.setMaxValue(59);
            numberPicker3.setMinValue(0);
            numberPicker3.setMaxValue(59);

            numberPicker2.setMinValue(0);
            numberPicker2.setMaxValue(59);

            AlertDialog.Builder builder;
            builder = new AlertDialog.Builder(getActivity(), R.style.Theme_Material_Dialog_Alert);


            builder.setTitle("Choose Value");


            builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {

                    dismiss();
                }
            });

            builder.setNegativeButton("CANCEL", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    dismiss();

                }
            });

            builder.setView(child);
            return builder.create();
        }




    }

Answer 1

您可以创建一个 Listener 接口(interface)，该接口(interface)在您的 Activity 中实现，并通过对 Activity 的引用在 DialogFragment 中使用。像这样的东西:

public class MyActivity extends Activity implements NumberPickerListener {
    ...
    @Override
    public void onValuesPicked(int first, int second, int third) {
        //Do work here.
    }
    ...
}

界面:

interface NumberPickerLisener {
    void onValuesPicked(int first, int second, int third);
}

在您的 fragment 中:

public class PickerDialog extends DialogFragment {

    NumberPickerListener listener;

    ...

    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {
        View child = getActivity().getLayoutInflater().inflate(R.layout.dialog, null);
        listener = (MyActivity)getActivity();

        ...

        builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                listener.onValuesPicked(numberPicker.getValue(), numberPicker2.getValue(), numberPicker3.getValue());
                dismiss();
            }
        });

        ...
    }




}