java - Android TimePicker 未给出所需结果

Question

您好，我正在尝试计算用户的 sleep 时间为 7.5。该应用程序应建议用户应在准确的时间上床 sleep 。例如，她选择上午 7:00 作为她的起床时间，应用程序会建议她在上午 11:30 之前去 sleep 。到目前为止我尝试过的是:

public class TimepickerActivity extends Activity implements TimePickerDialog.OnTimeSetListener {

Button btn1, btn2;
TimePicker picker;
TextView tv;

private int hour;
private int minute;

static final int TIME_DIALOG_ID = 999;

@Override
public void onCreate( Bundle savedInstanceState ) {
    super.onCreate(savedInstanceState);
    setContentView( R.layout.activity_timepicker );

    btn1 = (Button) findViewById (R.id.btnShow);
    btn2 = (Button) findViewById (R.id.btnSleepingTime);
    tv = (TextView) findViewById (R.id.textView1);
    picker = (TimePicker) findViewById (R.id.timePicker1);

    setCurrentTimeOnView();
    addListenerOnButton();

}


 // display current time
public void setCurrentTimeOnView() {


    final Calendar c = Calendar.getInstance();
    hour = c.get(Calendar.HOUR_OF_DAY);
    minute = c.get(Calendar.MINUTE);

    // set current time into textview
    tv.setText( new StringBuilder().append(pad(hour))
                                    .append(":").append(pad(minute)));

    // set current time into timepicker
    picker.setCurrentHour(hour);
    picker.setCurrentMinute(minute);

}

public void addListenerOnButton() {


    btn1.setOnClickListener(new OnClickListener() {

        public void onClick(View v) {

            showDialog(TIME_DIALOG_ID);

        }

    });

}

@Override
protected Dialog onCreateDialog(int id) {
    switch (id) {
    case TIME_DIALOG_ID:
        // set time picker as current time
        return new TimePickerDialog(this, 
                                     timePickerListener, hour, minute,false);

    }
    return null;
}

private TimePickerDialog.OnTimeSetListener timePickerListener = 
         new TimePickerDialog.OnTimeSetListener() {

    public void onTimeSet(TimePicker view, int selectedHour,
            int selectedMinute) {
        hour = selectedHour;
        minute = selectedMinute;

        Calendar c = Calendar.getInstance();
        c.add(Calendar.HOUR, - selectedHour);
        c.add(Calendar.MINUTE, - selectedMinute);

        // set current time into timepicker
        picker.setCurrentHour(hour + 7);
        picker.setCurrentMinute(minute + 30);

        // set current time into textview
        //tv.setText(new StringBuilder().append(pad(hour))
        //      .append(":").append(pad(minute)));

        tv.setText( picker.getCurrentHour().toString() + ":" + picker.getCurrentMinute().toString()  );



    }
};

private static String pad(int c) {
    if (c >= 10)
       return String.valueOf(c);
    else
       return "0" + String.valueOf(c);
}


public void onTimeSet(TimePicker view, int hourOfDay, int minute) {
    // TODO Auto-generated method stub

}



}

当我输入早上 7:00 作为起床时间时，结果是下午 2:30。但应该是中午 12:30。如有任何帮助，我们将不胜感激，谢谢。

Answer 1

不，这是正确的。如果您输入 7:00am + 7.5 小时 = 14:30 = 2:30 am。程序运行正常。

编辑:你几乎做到了:

public class TimepickerActivity extends Activity implements TimePickerDialog.OnTimeSetListener {

    private static final int SUB_HOUR = -7;
    private static final int SUB_MINUTE = -30;

    [...]

public void onTimeSet(TimePicker view, int selectedHour,
        int selectedMinute) {

    // Gets current time
    Calendar c = Calendar.getInstance();

    // Assign hour set in the picker
    c.set(Calendar.HOUR, selectedHour)
    c.set(Calendar.MINUTE, selectedMinute);

    // Have Calendar calculate the substraction of hours and minutes
    c.add(Calendar.HOUR, SUB_HOUR);
    c.add(Calendar.MINUTE, SUB_MINUTE);

    // Get the hour and the minute calculated
    hour = c.get(Calendar.HOUR);
    minute = c.get(Calendar.MINUTE);
    [...]

当然，这意味着之前的作业:

    hour = selectedHour;
    minute = selectedMinute;

现在没用了，您可以将其删除。

顺便说一下，你没有考虑到这一天，例如选择凌晨 1:30 将返回下午 6:00，但是是前一天。

编辑:我更正了我的代码。