android - 在 android 中验证 "from date"和 "to date"

Question

我是一个应用程序，用户必须在其中选择两个日期，即 from date 和 to date。这两个字段不应接受任何小于当前日期的日期。I浏览了本网站的一些帖子，并通过使用单个日期选择器对话框和单个 ondatesetListener 实现了此功能。

我的问题是我无法验证 to date 应该始终大于或等于 from date 的条件。请帮助我。我无法捕获开始日期，因为 Activity 日期被 Activity 结束日期覆盖 在此先感谢。以下是代码:

public class Leave_form extends Activity 
{       
    private static EditText tvDislpayResult;
    private Button startPickDate;
    private Button endPickDate;
    private Calendar startDate;
    private Calendar endDate;
    //private EditText startDateDisplay;
    //private EditText endDateDisplay;
    static final int DATE_DIALOG_ID = 0;
    private TextView startDateDisplay;
    private TextView endDateDisplay;
    private TextView activeDateDisplay;
    private Calendar activeDate;
    private Calendar currentDate;
    private Calendar fromDate;

    protected void onCreate(Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_leave_form);

        /*  capture our View elements for the start date function   */
        startDateDisplay = (EditText) findViewById(R.id.e_from_date);
        startPickDate = (Button) findViewById(R.id.Set_date1);

        /*get tday date  */   

        currentDate=Calendar.getInstance();
        Log.d("currentDate ",""+(currentDate.get(Calendar.DAY_OF_MONTH))+(currentDate.get(Calendar.MONTH)+1)+(currentDate.get(Calendar.YEAR)));

        /* get the current date */
        startDate = Calendar.getInstance();
        Log.d("startdate ",""+(startDate.get(Calendar.DAY_OF_MONTH))+(startDate.get(Calendar.MONTH)+1)+(startDate.get(Calendar.YEAR)));

        /* add a click listener to the button   */
        startPickDate.setOnClickListener(new View.OnClickListener()
        {
            public void onClick(View v) 
            {
                showDateDialog(startDateDisplay, startDate);
                Log.d("startDate-on click ",""+(startDate.get(Calendar.DAY_OF_MONTH))+(startDate.get(Calendar.MONTH)+1)+(startDate.get(Calendar.YEAR)));

            }
        });

        /* capture our View elements for the end date function */
        endDateDisplay = (EditText) findViewById(R.id.e_to_date);
        endPickDate = (Button) findViewById(R.id.Set_date2);

        /* get the current date */
        endDate = Calendar.getInstance();
        Log.d("endDate ",""+(endDate.get(Calendar.DAY_OF_MONTH))+(endDate.get(Calendar.MONTH)+1)+(endDate.get(Calendar.YEAR)));

        /* add a click listener to the button   */
        endPickDate.setOnClickListener(new View.OnClickListener()
        {
            public void onClick(View v)
            {
                showDateDialog(endDateDisplay, endDate);
                Log.d("endDate -on click",""+(endDate.get(Calendar.DAY_OF_MONTH))+(endDate.get(Calendar.MONTH)+1)+(endDate.get(Calendar.YEAR)));
            }
        });

        /* display the current date (this method is below)  */
       // updateDisplay(startDateDisplay, startDate);
       // updateDisplay(endDateDisplay, endDate);
    }

    private void updateDisplay(TextView dateDisplay, Calendar date) 
    {
        dateDisplay.setText(
                new StringBuilder()
                    // Month is 0 based so add 1
                    .append(date.get(Calendar.DAY_OF_MONTH) ).append("-")
                    .append(date.get(Calendar.MONTH)+1).append("-")
                    .append(date.get(Calendar.YEAR)).append(" "));

        Log.d("msg","date:"+(date.get(Calendar.DAY_OF_MONTH))+(date.get(Calendar.MONTH)+1)+(date.get(Calendar.YEAR)));

        fromDate=date;
    }

    public void showDateDialog(TextView dateDisplay, Calendar date)
    {
        Log.d("SDD", dateDisplay.getText().toString());
        Log.d("startdate ",""+(currentDate.get(Calendar.DAY_OF_MONTH))+(currentDate.get(Calendar.MONTH)+1)+(currentDate.get(Calendar.YEAR)));
       activeDateDisplay = dateDisplay;
        activeDate = date;
        showDialog(DATE_DIALOG_ID);
    }

    private OnDateSetListener dateSetListener = new OnDateSetListener()
    {
        @SuppressWarnings("deprecation")
        @Override
        public void onDateSet(DatePicker view, int year, int monthOfYear, int dayOfMonth) {
            activeDate.set(Calendar.YEAR, year);
            activeDate.set(Calendar.MONTH, monthOfYear);
            activeDate.set(Calendar.DAY_OF_MONTH, dayOfMonth);
            Log.d("activeDate-on dateset ",""+(activeDate.get(Calendar.DAY_OF_MONTH))+(activeDate.get(Calendar.MONTH)+1)+(activeDate.get(Calendar.YEAR)));

            if(currentDate.after(activeDate)|(currentDate.equals(activeDate)))
            {
                Toast toast=Toast.makeText(Leave_form.this, "Please select a valid date", Toast.LENGTH_LONG);
                toast.setGravity(Gravity.CENTER, 0, 0);
                toast.show();


            }
            else
            {
                if((currentDate.after(activeDate)|(currentDate.equals(activeDate)))&&(startDateDisplay.getText().toString()!=null))
                {
                    Log.d("startDate-on click ",""+(startDate.get(Calendar.DAY_OF_MONTH))+(startDate.get(Calendar.MONTH)+1)+(startDate.get(Calendar.YEAR)));
                    if(startDate.before(activeDate))
                    {
                        updateDisplay(activeDateDisplay, activeDate);
                    }

                    else
                    {
                        Toast.makeText(getApplicationContext(), "enter valid date", Toast.LENGTH_SHORT).show();
                        /*AlertDialog alertDialog=new AlertDialog.Builder(Leave_form.this).create();

                        alertDialog.setMessage("Choose a valid date");

                        alertDialog.setButton("OK", new DialogInterface.OnClickListener() {

                            @Override
                            public void onClick(DialogInterface dialog, int which) {
                                // TODO Auto-generated method stub

                            }
                        });
                        alertDialog.show();*/
                    }
                }
                else
                {
                    updateDisplay(activeDateDisplay, activeDate);
                }

           }

            unregisterDateDisplay();
        }
    };

    private void unregisterDateDisplay() 
    {
        Log.d("startdate ",""+(currentDate.get(Calendar.DAY_OF_MONTH))+(currentDate.get(Calendar.MONTH)+1)+(currentDate.get(Calendar.YEAR)));
        Log.d("from date:","-"+activeDate.DAY_OF_MONTH+activeDate.MONTH+activeDate.YEAR);
        activeDateDisplay = null;
        activeDate = null;
    }

    @Override
    protected Dialog onCreateDialog(int id) {
        switch (id) {

            case DATE_DIALOG_ID:
                Log.d("fromdate","msg");
                Log.d("id",""+DATE_DIALOG_ID);
                return new DatePickerDialog(this, dateSetListener, activeDate.get(Calendar.YEAR), activeDate.get(Calendar.MONTH), activeDate.get(Calendar.DAY_OF_MONTH));
        }
        return null;
    }

    @Override
    protected void onPrepareDialog(int id, Dialog dialog) {
        super.onPrepareDialog(id, dialog);
        switch (id) {
            case DATE_DIALOG_ID:
                Log.d("id",""+DATE_DIALOG_ID);
                ((DatePickerDialog) dialog).updateDate(activeDate.get(Calendar.YEAR), activeDate.get(Calendar.MONTH), activeDate.get(Calendar.DAY_OF_MONTH));
                break;
        }
    }

    public void leave(View view)
    {
        Intent intent1=new Intent(this,Rough.class);
        setContentView(R.layout.activity_rough);
        startActivity(intent1);
    }
    public void logout(View view)
    {
        Intent intent2=new Intent (this,MainActivity.class);
        setContentView(R.layout.activity_main);
        startActivity(intent2);
    }
}

Answer 1

最好改成这样的代码:

if((currentDate.after(activeDate)|(currentDate.equals(activeDate)))&&(startDateDisplay.getText().toString()!=null))

多个 if block ，例如:

if((currentDate.after(activeDate)||(currentDate.equals(activeDate))
    if(!startDateDisplay.getText().toString().equals(null))

仔细注意差异!

也看看这个 answer here