java - 设置textview值，之后再两个textview获取值

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Android calculate days between two dates

（11个答案）



How to get number of days between two calendar instance?

（11个答案）


2天前关闭。





我创建一个预订酒店的应用程序，它具有3 textview和2按钮来选择日期。如果单击按钮，它将显示一个日期，所选日期将显示为2个文本视图。如何在第三文本视图中显示日期之间的日期？
这是我的代码（第三个文本视图未显示为日期之间的日期）

protected void onCreate(@Nullable Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);


            dateFormatter = new SimpleDateFormat("dd-MM-yyyy", Locale.US);

            tvDateResult = (TextView) findViewById(R.id.tv_dateresult);
            res = findViewById(R.id.tv_dateresult1);
            ress = findViewById(R.id.tv_dateresult2);
            btDatePicker = (Button) findViewById(R.id.bt_datepicker);
            date = findViewById(R.id.bt_datepicker1);
            get = findViewById(R.id.getprice);

            date.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    showDateDialog2();
                }

            });

            btDatePicker.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    showDateDialog();
                }

            });




                }




            private void showDateDialog2() {

                Calendar newCalendar = Calendar.getInstance();


                datePickerDialog = new DatePickerDialog(this, new DatePickerDialog.OnDateSetListener() {

                    @Override
                    public void onDateSet(DatePicker view, int year, int monthOfYear, int dayOfMonth) {

                        Calendar newDate = Calendar.getInstance();
                        newDate.set(year, monthOfYear, dayOfMonth);

                        res.setText(dateFormatter.format(newDate.getTime()));
                    }

                },newCalendar.get(Calendar.YEAR), newCalendar.get(Calendar.MONTH), newCalendar.get(Calendar.DAY_OF_MONTH));

                datePickerDialog.show();

                if(tvDateResult !=null || res !=null) {
                    try {
                        String a = tvDateResult.getText().toString();
                        String b = res.getText().toString();

                        Date aa = dateFormatter.parse(a);
                        Date bb = dateFormatter.parse(b);

                        long diff = bb.getTime() - aa.getTime() / 24 * 60 * 60 * 1000;


                        ress.setText((int) TimeUnit.DAYS.convert(diff, TimeUnit.MILLISECONDS));


                    } catch (ParseException e) {
                        e.printStackTrace();
                    }
                }
             }

        private void showDateDialog(){


            Calendar newCalendar = Calendar.getInstance();


            datePickerDialog = new DatePickerDialog(this, new DatePickerDialog.OnDateSetListener() {

                @Override
                public void onDateSet(DatePicker view, int year, int monthOfYear, int dayOfMonth) {

                    Calendar newDate = Calendar.getInstance();
                    newDate.set(year, monthOfYear, dayOfMonth);

                    tvDateResult.setText(dateFormatter.format(newDate.getTime()));
                }

            },newCalendar.get(Calendar.YEAR), newCalendar.get(Calendar.MONTH), newCalendar.get(Calendar.DAY_OF_MONTH));

            datePickerDialog.show();
}

最佳答案

声明2个全局变量：

Calendar date1 = null, date2 = null;
在两个日期选择器的onDateSet方法中，将所选日期保存在全局变量中。


在第一个日期选择器的onDateSet中，

Calendar newDate = Calendar.getInstance();
date1 = newDate
updateTextView()

同样，在第二个日期选择器的onDateSet中，

Calendar newDate = Calendar.getInstance();
date1 = newDate
updateTextView()

从两个onDateSet方法中调用一个方法。

private void updateTextView() {
    if(date1 != null && date2 != null) {
        tvDateResult .setText(dateFormatter.format(daysBetween(date1,date2)));
    }
}

public static long daysBetween(Calendar startDate, Calendar endDate) {

    // Make sure we don't change the parameter passed
    Calendar newStart = Calendar.getInstance();
    newStart.setTimeInMillis(startDate.getTimeInMillis());
    newStart.set(Calendar.HOUR_OF_DAY, 0);
    newStart.set(Calendar.MINUTE, 0);
    newStart.set(Calendar.SECOND, 0);
    newStart.set(Calendar.MILLISECOND, 0);

    Calendar newEnd = Calendar.getInstance();
    newEnd.setTimeInMillis(endDate.getTimeInMillis());
    newEnd.set(Calendar.HOUR_OF_DAY, 0);
    newEnd.set(Calendar.MINUTE, 0);
    newEnd.set(Calendar.SECOND, 0);
    newEnd.set(Calendar.MILLISECOND, 0);

    long end = newEnd.getTimeInMillis();
    long start = newStart.getTimeInMillis();
    return TimeUnit.MILLISECONDS.toDays(Math.abs(end - start));
}

参考：How to get number of days between two calendar instance?