i创建了预订酒店的应用程序，它具有3个textview和2个按钮来选择日期。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textview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();
}
声明2个全局变量：
日历date1 = null，date2 = null;
在两个日期选择器的onDateSet方法中，将选定的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()
类似地，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）））; }}
公共静态long daysBetween（日历startDate，日历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));
}