如何修复片段对话框中的显示方法

Question

我编写此代码是为了在我运行应用程序停止工作时在我的项目中显示时间。但是，当我删除 show 方法程序时，当我按下 Button

时，程序没有显示任何内容

任何帮助请

这是代码

public class AlarmFragment extends Fragment implements 
    TimePickerDialog.OnTimeSetListener{
    private Button clockBtn;
    private TextView time;
 public AlarmFragment() {
    // Required empty public constructor
}


@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    // Inflate the layout for this fragment
    View view= inflater.inflate(R.layout.fragment_alarm, container, false);
    time = view.findViewById(R.id.alarm_time);
    clockBtn= view.findViewById(R.id.clock_btn);
    clockBtn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            DialogFragment clock= new TimeClock();
              ///////////show method /////////
             clock.show(getActivity().getSupportFragmentManager(),"Time Picker");


        }
    });
    return view;
}
  @Override
     public void onTimeSet(TimePicker view, int hourOfDay, int minute) {
        time.setText("Time:" + hourOfDay +" : "+minute);
      }}

这是时钟片段

import android.app.Dialog;
import android.app.TimePickerDialog;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v4.app.DialogFragment;
import java.util.Calendar;

public class TimeClock extends DialogFragment {
@NonNull
@Override
public Dialog onCreateDialog(@Nullable Bundle savedInstanceState) {
    Calendar c = Calendar.getInstance();
    int hour = c.get(Calendar.HOUR_OF_DAY);
    int minute = c.get(Calendar.MINUTE);
  return new TimePickerDialog(getActivity(), (TimePickerDialog.OnTimeSetListener) getActivity(), hour, minute, android.text.format.DateFormat.is24HourFormat(getActivity()));
    }
}

Edit:- 所以我改了上面的return语句，然后works.ButAlarmFragment中的onTimeSet方法没有执行我是这样做的：-

Activity activity = new AlarmFragment().getActivity();

        return new TimePickerDialog(getActivity(), (TimePickerDialog.OnTimeSetListener)activity, hour, minute, android.text.format.DateFormat.is24HourFormat(getActivity()));

Answer 1

在承载您的 AlarmFragment 的 Activity 中，您必须实施 TimePickerDialog.OnTimeSetListener。

例如：

public class MainActivity implements TimePickerDialog.OnTimeSetListener {

    ...

    @Override
    public void onTimeSet(TimePicker view, int hourOfDay, int minute) {
        Toast.makeText(this, "chosen hour of day: " + hourOfDay, Toast.LENGTH_LONG).show();
    }
}

Answer 2

你得到 ClassCastException 因为你的 getActivity 不是 TimePickerDialog.OnTimeSetListener，但你的 AlarmFragment 是：

// this is where it fails, change this line, do not copy
return new TimePickerDialog(getActivity(), (TimePickerDialog.OnTimeSetListener) getActivity(), hour, minute, android.text.format.DateFormat.is24HourFormat(getActivity()));

您可以重构 TimeClock class 以委托侦听器：

public class TimeClock extends DialogFragment {

    private TimePickerDialog.OnTimeSetListener listener;

    public void setOnTimeSetListener(TimePickerDialog.OnTimeSetListener listener) {
        this.listener = listener;
    }

    @NonNull
    @Override
    public Dialog onCreateDialog(@Nullable Bundle savedInstanceState) {
        Calendar c = Calendar.getInstance();
        int hour = c.get(Calendar.HOUR_OF_DAY);
        int minute = c.get(Calendar.MINUTE);
        // Now delegates the listener to the constructor
        return new TimePickerDialog(getActivity(), listener, hour, minute, android.text.format.DateFormat.is24HourFormat(getActivity()));
    }
}

并在TimeClock.show之前设置你的监听器：

DialogFragment clock= new TimeClock();
clock.setOnTimeSetListener(this);
clock.show(getActivity().getSupportFragmentManager(), "Time Picker");

如何修复片段对话框中的显示方法

How to fix show method in FragmentDialog

java

android

fragment

android-fragments

android-dialogfragment