【发布时间】：2021-07-23 16:14:44
【问题描述】：
我正在尝试将 spinner.setOnItemSelectedListener 中的值传递给包含日期字符串的字符串。我有两个月份和年份的微调器，这里我只显示月份微调器，因为如果我得到月份微调器的解决方案，那么它也将与年份相同。
month_spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
if (parent.getId() == R.id.month_spinner){
seltmont = parent.getSelectedItem().toString();
Toast.makeText(MainActivity.this, "Selected Month: " + seltmont, Toast.LENGTH_SHORT).show();
textviewMonth.setText(seltmont);
setMonthView();
}
}
@Override
public void onNothingSelected(AdapterView<?> parent) {
}
});
我尝试像这样访问微调器值：- String month = month_spinner.getSelectedItem().toString();
并尝试将微调器onItemSelectListener 值传递给combinedString 字符串变量，如下所示：-
combinedString = "01/" + month + "/" + year ;
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("dd/MMMM/yyyy");
selectdate = LocalDate.parse(combinedString, formatter);
我在微调器中已经预选的组合字符串中获得了默认值，但是
当用户尝试更改微调器中显示的默认值时，它不会更改该值。它在组合字符串中给出空值。
谁能帮我如何将值从onItemSelectListener 传递给combinedString
是因为方法的范围（'{}'）还是因为私有或公共变量声明。
请帮忙。
顺便说一句，整个代码都在 JAVA 中。 这是完整的代码：-
public class MainActivity extends AppCompatActivity implements CalendarAdapter.OnItemListener {
TextView monthYearText, textviewMonth,textviewYear,textviewYearnMonth;
RecyclerView calendarReyclerView;
LocalDate selectdate;
private Spinner month_spinner,spinYear;
String [] months;
String combinedString;
String selectedMonth;
String seltmont;
String selctYear;
@SuppressLint("SetTextI18n")
@RequiresApi(api = Build.VERSION_CODES.O)
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
textviewMonth = findViewById(R.id.textviewMonth);
textviewYear = findViewById(R.id.textviewYear);
//for testing
textviewYearnMonth = findViewById(R.id.textviewYearnMonth);
month_spinner = findViewById(R.id.month_spinner);
spinYear = findViewById(R.id.yearspin);
populateSpinnerMonth();
populateSpinnerYear();
initWidget();
selectdate = LocalDate.now();
setMonthView();
//---- on click listener ---//
month_spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
if (parent.getId() == R.id.month_spinner){
seltmont = parent.getSelectedItem().toString();
Toast.makeText(MainActivity.this, "Selected Month: " + seltmont, Toast.LENGTH_SHORT).show();
textviewMonth.setText(seltmont);
setMonthView();
}
}
@Override
public void onNothingSelected(AdapterView<?> parent) {
}
});
spinYear.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
if (parent.getId() == R.id.yearspin){
selctYear = parent.getSelectedItem().toString();
Toast.makeText(MainActivity.this, "Selected Year" + selctYear, Toast.LENGTH_SHORT).show();
textviewYear.setText(selctYear);
setMonthView();
}
}
@Override
public void onNothingSelected(AdapterView<?> parent) {
}
});
// ---- on click listener ---//
String month = month_spinner.getSelectedItem().toString();
String year= spinYear.getSelectedItem().toString();
// String month = textviewMonth.getText().toString();
//String year = textviewYear.getText().toString();
//combinedString = "16/09/2019";
combinedString = "01/" + month + "/" + year ;
// combinedString = "01/" + mon + "/" + year ;
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("dd/MMMM/yyyy");
selectdate = LocalDate.parse(combinedString, formatter);
/* //not working
String mon = textviewMonth.getText().toString();
Log.d("month","code is going here");
textviewYearnMonth.setText(mon);
Log.d("month","code cross the textviewYearnMonth"); */
// textviewYearnMonth.setText(seltmont);
}
private void populateSpinnerYear() {
ArrayList<String> years = new ArrayList<String>();
int thisYear = Calendar.getInstance().get(Calendar.YEAR);
for (int i = 1950; i <= thisYear; i++){
years.add(Integer.toString(i));
}
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item,years);
spinYear.setAdapter(adapter);
}
private void populateSpinnerMonth() {
months = new DateFormatSymbols().getMonths();
ArrayAdapter<String> monthAdapter = new ArrayAdapter<>(this, android.R.layout.simple_spinner_item,months);
monthAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
month_spinner.setAdapter(monthAdapter);
}
@RequiresApi(api = Build.VERSION_CODES.O)
private void setMonthView() {
monthYearText.setText(monthYearFromDate(selectdate));
ArrayList<String> daysInMonth = daysInMonthArray(selectdate);
CalendarAdapter calendarAdapter = new CalendarAdapter(daysInMonth, this);
RecyclerView.LayoutManager layoutManager = new GridLayoutManager(getApplicationContext(),7); //for calendar columns
calendarReyclerView.setLayoutManager(layoutManager);
calendarReyclerView.setAdapter(calendarAdapter);
}
@RequiresApi(api = Build.VERSION_CODES.O)
private ArrayList<String> daysInMonthArray(LocalDate date) {
ArrayList<String> daysInMonthArray = new ArrayList<>();
YearMonth yearMonth = YearMonth.from(date);
int daysInMonth = yearMonth.lengthOfMonth();
LocalDate firstOfMonth = selectdate.withDayOfMonth(1);
int dayOfWeek = firstOfMonth.getDayOfWeek().getValue();
for(int i = 1; i <= 42; i++)
{
if(i <= dayOfWeek || i > daysInMonth + dayOfWeek)
{
daysInMonthArray.add("");
}
else
{
daysInMonthArray.add(String.valueOf(i - dayOfWeek));
}
}
return daysInMonthArray;
}
@RequiresApi(api = Build.VERSION_CODES.O)
private String monthYearFromDate(LocalDate date){
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("MMMM yyyy");
return date.format(formatter);
}
private void initWidget() {
calendarReyclerView = findViewById(R.id.calendarRecyclerView);
monthYearText = findViewById(R.id.monthYearTV);
}
@RequiresApi(api = Build.VERSION_CODES.O)
public void previousMonthAction(View view) {
selectdate = selectdate.minusMonths(1);
setMonthView();
}
@RequiresApi(api = Build.VERSION_CODES.O)
public void nextMonthAction(View view) {
selectdate = selectdate.plusMonths(1);
setMonthView();
}
@RequiresApi(api = Build.VERSION_CODES.O)
@Override
public void onItemClick(int position, String dayText) {
if(!dayText.equals(""))
{
String message = "Selected Date " + dayText + " " + monthYearFromDate(selectdate);
Toast.makeText(this, message, Toast.LENGTH_LONG).show();
}
}
我附上了两张输出图片：
首次发布的初始阶段 ->图片 1
在我更改微调器值后 ->Image 2
【问题讨论】：
标签： java android android-spinner datetimeformatter