如何在Android中的游标适配器的bindview中进行日期解析和格式化

Question

I have saved my dates in my sqlite table like 2016-04-20 and I want my listview display them as 20/4/2016 and I use the following inside the bindview of a cursor adapter

String InitialDate=cursor.getString(cursor.getColumnIndex(cursor.getColumnName(2)));

SimpleDateFormat curFormater = new SimpleDateFormat("yyyy-MM-dd");
Date dateObj = curFormater.parse(InitialDate);
SimpleDateFormat postFormater = new SimpleDateFormat("dd/MM/yyyy");
String newDateStr = postFormater.format(dateObj);
textViewDate.setText(newDateStr);

but before I do anything the part of parse says Unhandled Exception java.text.ParseException I have import of

import java.text.SimpleDateFormat;
import java.util.Date;

Answer 1

These is because the method you are calling can throw an exception and you are not taking care of it.. look:

Date java.text.DateFormat.parse(String source) throws ParseException

Throws: ParseException - if the beginning of the specified string cannot be parsed.

This basically means, if you try to convert a non-sense into a date, the java.text.DateFormat class will try its best to but if not possible will throw the exception, that you must either catch using the properly try-catch statement or just re throwing the exception so others can take care of it..

So at the end your options are:

1. Re throw the exception

t

public static void main(String[] args) throws ParseException {
    String InitialDate = new String("2016-04-20");
    SimpleDateFormat curFormater = new SimpleDateFormat("yyyy-MM-dd");
    Date dateObj = curFormater.parse(InitialDate);
    SimpleDateFormat postFormater = new SimpleDateFormat("dd/MM/yyyy");
    String newDateStr = postFormater.format(dateObj);
}

2. Use the properly try catch

Use....

public static void main(String[] args) {
    String InitialDate = new String("2016-04-20");
    SimpleDateFormat curFormater = new SimpleDateFormat("yyyy-MM-dd");
    Date dateObj;
    try {
        dateObj = curFormater.parse(InitialDate);
        SimpleDateFormat postFormater = new SimpleDateFormat("dd/MM/yyyy");
        String newDateStr = postFormater.format(dateObj);
    } catch (ParseException e) {
        e.printStackTrace();
        System.err.println("a non sense was here");
    }
}

Answer 2

you should use try/catch block for parse method call because it can produce checked exception :

Date dateObj = null;
try {
    dateObj = curFormater.parse(InitialDate);
} catch (ParseException e) {
    e.printStackTrace();
}

or you can just rethrow this exception from your method (you should use throws ParseException clause in method signature)

via documentation :

Checked exceptions are subject to the Catch or Specify Requirement. All exceptions are checked exceptions, except for those indicated by Error, RuntimeException, and their subclasses.