如何创建Spinner以显示当前和下30个日期

Question

如何创建日期微调器,它将EditText中的当前日期显示为Spinner中的默认日期和未来日期(例如,接下来的30天)

我在许多应用程序中使用了日期选择器,所以我熟悉日期选择器对话框,但对日期微调器没有任何想法.

注意
请不要告诉我如何将EditText设置为Spinner的样式

编辑:1推荐人@erakitin

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_date);

    Spinner spinnerDateIn = (Spinner) findViewById(R.id.spinnerDateIn);
    Spinner spinnerDateOut = (Spinner) findViewById(R.id.spinnerDateOut);       

    spinnerDateIn.setAdapter(new CalendarSpinnerAdapter(SpinnerDateActivity.this, 30));         

}

编辑:2@erakitin在新的更新中推荐

CalendarSpinnerAdapter mSpinnerDateInAdapter = new CalendarSpinnerAdapter(SpinnerDateActivity.this, 30);
        spinnerDate.setAdapter(mSpinnerDateInAdapter);

        spinnerDate.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
                spinnerDate.setSelection(position);
            }

            @Override
            public void onNothingSelected(AdapterView<?> parent) {

            }
        });

现在,试图在String中获取所选Item的值但得到:java.util.GregorianCalendar,我在哪里做错了？

strDate = spinnerDate.getSelectedItem().toString();

Answer 1

下面有一个简单的适配器示例Spinner.

public class CalendarSpinnerAdapter extends BaseAdapter {

    private SimpleDateFormat mDateFormat = new SimpleDateFormat("d MMM yyyy");

    private LayoutInflater mInflater;
    private Calendar mCalendar;
    private int mDayCount;
    private int mLastRequestedDay = 0;

    public CalendarSpinnerAdapter(Context context, int dayCount) {
        mInflater = LayoutInflater.from(context);
        mDayCount = dayCount;
        mCalendar = Calendar.getInstance();
    }

    @Override
    public int getCount() {
        return mDayCount;
    }

    @Override
    public Calendar getItem(int position) {
        mCalendar.add(Calendar.DAY_OF_YEAR, position - mLastRequestedDay);
        mLastRequestedDay = position;
        return mCalendar;
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        if (convertView == null) {
            convertView = mInflater.inflate(android.R.layout.simple_spinner_dropdown_item, parent, false);
        }

        Calendar item = getItem(position);
        ((TextView) convertView).setText(mDateFormat.format(item.getTimeInMillis()));

        return convertView;
    }

    @Override
    public View getDropDownView(int position, View convertView, ViewGroup parent) {
        return getView(position, convertView, parent);
    }
}

如何使用它来显示当前日期和接下来的29天:

mDateSpinner.setAdapter(new CalendarSpinnerAdapter(getActivity(), 30));

UPD:

我们应该在adapter的构造函数中添加一个参数来设置开始日期:

public CalendarSpinnerAdapter(Context context, Calendar startDate, int dayCount) {
    mInflater = LayoutInflater.from(context);
    mDayCount = dayCount;
    mCalendar = Calendar.getInstance();
    mCalendar.setTimeInMillis(startDate.getTimeInMillis());
}

然后添加监听器以便spinnerDateIn我们可以初始化第二个微调器:

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_date);

    Spinner spinnerDateIn = (Spinner) findViewById(R.id.spinnerDateIn);
    final Spinner spinnerDateOut = (Spinner) findViewById(R.id.spinnerDateOut);

    mSpinnerDateInAdapter = new CalendarSpinnerAdapter(SpinnerDateActivity.this, Calendar.getInstance(), 30);
    spinnerDateIn.setAdapter(mSpinnerDateInAdapter);

    spinnerDateIn.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
        @Override
        public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
            Calendar dateIn = Calendar.getInstance();
            dateIn.setTimeInMillis(mSpinnerDateInAdapter.getItem(position).getTimeInMillis());
            dateIn.add(Calendar.DAY_OF_YEAR, 1); // add one day
            mSpinnerDateOutAdapter = new CalendarSpinnerAdapter(SpinnerDateActivity.this, dateIn, 30);
            spinnerDateOut.setAdapter(mSpinnerDateOutAdapter);
        }

        @Override
        public void onNothingSelected(AdapterView<?> parent) {

        }
    });
}

我没有尝试这个代码,但它应该工作.

UPD2:

spinnerDate.setSelection(position)返回Calendar类实例.如果您想要选择日期,String您应该格式化它.尝试使用以下方法:

private String getSelectedDateAsString(Spinner dateSpinner) {
    Calendar selectedDate = (Calendar) dateSpinner.getSelectedItem();
    return new SimpleDateFormat("d MMM yyyy").format(selectedDate.getTimeInMillis());
}