我有以下PHP代码。 我想知道如何将日期格式从yyyy-mm-dd更改为dd-mm-yyyy。 我试图自己做这个，但是有很多代码，我只是无法弄清楚如何去做。
/********************* PUBLIC **********************/
/**
* print out the calendar
*/
public function show() {
$year = null;
$month = null;
if(null==$year&&isset($_GET['year'])){
$year = $_GET['year'];
}else if(null==$year){
$year = date("Y",time());
}
if(null==$month&&isset($_GET['month'])){
$month = $_GET['month'];
}else if(null==$month){
$month = date("m",time());
}
$this->currentYear=$year;
$this->currentMonth=$month;
$this->daysInMonth=$this->_daysInMonth($month,$year);
$content='<div id="calendar">'.
'<a href="add_event.php"><font color="white" size="4"><b>Add event</b></font></a><br><br>'.
'<div class="box">'.
$this->_createNavi().
'</div>'.
'<div class="box-content">'.
'<ul class="label">'.$this->_createLabels().'</ul>';
$content.='<div class="clear"></div>';
$content.='<ul class="dates">';
$weeksInMonth = $this->_weeksInMonth($month,$year);
// Create weeks in a month
for( $i=0; $i<$weeksInMonth; $i++ ){
//Create days in a week
for($j=1;$j<=7;$j++){
$content.=$this->_showDay($i*7+$j);
}
}
$content.='</ul>';
$content.='<div class="clear"></div>';
$content.='</div>';
$content.='</div>';
return $content;
}
/********************* PRIVATE **********************/
/**
* create the li element for ul
*/
private function _showDay($cellNumber){
if($this->currentDay==0){
$firstDayOfTheWeek = date('N',strtotime($this->currentYear.'-'.$this->currentMonth.'-01'));
if(intval($cellNumber) == intval($firstDayOfTheWeek)){
$this->currentDay=1;
}
}
if( ($this->currentDay!=0)&&($this->currentDay<=$this->daysInMonth) ){
$this->currentDate = date('Y-m-d',strtotime($this->currentYear.'-'.$this->currentMonth.'-'.($this->currentDay)));
$cellContent = $this->currentDay;
$this->currentDay++;
}else{
$this->currentDate =null;
$cellContent=null;
}
$today_day = date("d");
$today_mon = date("m");
$today_yea = date("Y");
$class_day = ($cellContent == $today_day && $this->currentMonth == $today_mon && $this->currentYear == $today_yea ? "this_today" : "nums_days");
$wyn = '<li class="' . $class_day . '">';
require_once "mysql.php";
if(strlen($cellContent)){
$zap = "SELECT e_id FROM events WHERE e_data = '".$this->currentYear."-".$this->currentMonth."-".$cellContent."'";
$wyk = mysql_query($zap);
if(mysql_num_rows($wyk)>0) $wyn .= "<img src='img/icon1.png'>";
}
$wyn .= "<a href=\"show.php?date=";
$wyn .= $this->currentYear;
$wyn .= "-";
$wyn .= $this->currentMonth;
$wyn .= "-";
$wyn .= $cellContent;
$wyn .= "\">";
$wyn .= $cellContent;
$wyn .= "</a>";
$wyn .= '</li>' . "\r\n";
return $wyn;
}
/**
* create navigation
*/
private function _createNavi(){
$nextMonth = $this->currentMonth==12?1:intval($this->currentMonth)+1;
$nextYear = $this->currentMonth==12?intval($this->currentYear)+1:$this->currentYear;
$preMonth = $this->currentMonth==1?12:intval($this->currentMonth)-1;
$preYear = $this->currentMonth==1?intval($this->currentYear)-1:$this->currentYear;
return
'<div class="header">'.
'<a class="prev" href="'.$this->naviHref.'?month='.sprintf('%02d',$preMonth).'&year='.$preYear.'">Prev</a>'.
'<span class="title">'.date('M Y',strtotime($this->currentYear.'-'.$this->currentMonth.'-1')).'</span>'.
'<a class="next" href="'.$this->naviHref.'?month='.sprintf("%02d", $nextMonth).'&year='.$nextYear.'">Next</a>'.
'</div>';
}
/**
* create calendar week labels
*/
private function _createLabels(){
$content='';
foreach($this->dayLabels as $index=>$label){
$content.='<li class="'.($label==6?'end title':'start title').' title">'.$label.'</li>';
}
return $content;
}
/**
* calculate number of weeks in a particular month
*/
private function _weeksInMonth($month=null,$year=null){
if( null==($year) ) {
$year = date("Y",time());
}
if(null==($month)) {
$month = date("m",time());
}
// find number of days in this month
$daysInMonths = $this->_daysInMonth($month,$year);
$numOfweeks = ($daysInMonths%7==0?0:1) + intval($daysInMonths/7);
$monthEndingDay= date('N',strtotime($year.'-'.$month.'-'.$daysInMonths));
$monthStartDay = date('N',strtotime($year.'-'.$month.'-01'));
if($monthEndingDay<$monthStartDay){
$numOfweeks++;
}
return $numOfweeks;
}
/**
* calculate number of days in a particular month
*/
private function _daysInMonth($month=null,$year=null){
if(null==($year))
$year = date("Y",time());
if(null==($month))
$month = date("m",time());
return date('t',strtotime($year.'-'.$month.'-01'));
}
}
?>