如何从私有函数内引用对象

Question

I am using Mixpanel's PHP API and want to call mp->track.

In this case, the mp->track is defined as an object in the mixpanel library, called via require(mixpanel.php).

Typically, this would work fine:

require ('mixpanel-php/lib/Mixpanel.php');
$mp = Mixpanel::getInstance("XXX");
$mp->track('Session');

However, I want to call mp->track() from within a private function, but the following gives an object not defined error:

require ('mixpanel-php/lib/Mixpanel.php');
$mp = Mixpanel::getInstance("XXX")

private function startSession() {

$mp->track('Session');

}

Answer 1

Apparently the $mp variable is not accessible in the scope of the startSession() method. This is because it is not global. One solution would be to set the $mp global, but this is not a good software design. You should either pass it as a function variable

private function startSession($mp) {
    $mp->track('Session');
}

or you should get the instance itself in the private method

private function startSession() {
    Mixpanel::getInstance("XXX")->track('Session');
}