DialogFragment - 屏幕旋转之后保持监听器 [英] DialogFragment - retaining listener after screen rotation

问题描述

我有它创建了一个DatePickerDialog一个DialogFragment。我使用了一个名为的newInstance ，以便使用默认的空构造函数设置的初始值的静态方法。但是，我怎么设置监听器？屏幕旋转后，在完成按钮点击时，听者不会做任何事情，因为它不存在。

 公共类DatePickerFragment扩展DialogFragment {
    公共静态最后弦乐ARG_YEAR =一年;
    公共静态最后弦乐ARG_MONTH =月;
    公共静态最后弦乐ARG_DAY =一天;

    私人OnDateSetListener listener_;

    公共静态DatePickerFragment的newInstance（OnDateSetListener监听器，INT年，月整型，INT日）{
        最后DatePickerFragment date_picker =新DatePickerFragment（）;
        date_picker.setListener（听众）;

        最后的捆绑参数=新包（）;
        arguments.putInt（ARG_YEAR，一年）;
        arguments.putInt（ARG_MONTH，月）;
        arguments.putInt（ARG_DAY，日）;
        date_picker.setArguments（参数）;

        返回date_picker;
    }

    私人无效使用setListener（OnDateSetListener监听器）{
        listener_ =侦听器;
    }

    @覆盖
    公共对话onCreateDialog（包saved_instance_state）{
        最后的捆绑参数= getArguments（）;
        最终诠释年= arguments.getInt（ARG_YEAR）;
        最终诠释一个月= arguments.getInt（ARG_MONTH）;
        最终诠释天= arguments.getInt（ARG_DAY）;

        返回新DatePickerDialog（getActivity（），listener_，年，月，日）;
    }
}
 

解决方案

  

不过，我怎么设置监听器？

您更新了活动的的onCreate 方法监听器参考：

 私人OnDateSetListener MODS =新OnDateSetListener（）{

    @覆盖
    公共无效onDateSet（DatePicker的观点，年整型，诠释monthOfYear，
            INT DAYOFMONTH）{
             //做重要的东西
    }
};
 

和的onCreate 方法：

 如果（savedInstanceState！= NULL）{
    DatePickerFragment DPF =（DatePickerFragment）getSupportFragmentManager（）
            .findFragmentByTag（theTag？）;
    如果（DPF！= NULL）{
        dpf.setListener（MODS）;
    }
}
 

I have a DialogFragment which creates a DatePickerDialog. I'm using a static method called newInstance to set the initial values in order to use the default empty constructor. However, how am I supposed to set the listener? After the screen rotation, when clicking in the "Done" button, the listener doesn't do anything since it does not exist.

public class DatePickerFragment extends DialogFragment {
    public static final String ARG_YEAR = "year";
    public static final String ARG_MONTH = "month";
    public static final String ARG_DAY = "day";

    private OnDateSetListener listener_;

    public static DatePickerFragment newInstance(OnDateSetListener listener, int year, int month, int day) {
        final DatePickerFragment date_picker = new DatePickerFragment();
        date_picker.setListener(listener);

        final Bundle arguments = new Bundle();
        arguments.putInt(ARG_YEAR, year);
        arguments.putInt(ARG_MONTH, month);
        arguments.putInt(ARG_DAY, day);
        date_picker.setArguments(arguments);

        return date_picker;
    }

    private void setListener(OnDateSetListener listener) {
        listener_ = listener;
    }

    @Override
    public Dialog onCreateDialog(Bundle saved_instance_state) {
        final Bundle arguments = getArguments();
        final int year = arguments.getInt(ARG_YEAR);
        final int month = arguments.getInt(ARG_MONTH);
        final int day = arguments.getInt(ARG_DAY);

        return new DatePickerDialog(getActivity(), listener_, year, month, day);
    }
}

解决方案

However, how am I supposed to set the listener?

You update the listener reference in the onCreate method of the Activity:

private OnDateSetListener mOds = new OnDateSetListener() {

    @Override
    public void onDateSet(DatePicker view, int year, int monthOfYear,
            int dayOfMonth) {
             // do important stuff
    }
};

and in the onCreate method:

if (savedInstanceState != null) {
    DatePickerFragment dpf = (DatePickerFragment) getSupportFragmentManager()
            .findFragmentByTag("theTag?");
    if (dpf != null) {
        dpf.setListener(mOds);
    }
}

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