php - 注意：未定义的索引：在类->数组中

Question

这是代码：

class app {
    public $conf = array();
    public function init(){
       global $conf;
       $conf['theme']   = 'default';
       $conf['favicon'] = 'favicon.ico';
    }
    public function site_title(){
        return 'title';
    }
}

$app = new app;
$app->init();


//output
echo $app->conf['theme'];

我得到这个错误：

Notice: Undefined index: theme in C:\xampp\htdocs\...\trunk\test.php on line 21

我哪里出错了，有没有更简单的方法来获得相同的结果？

Answer 1

您正在填充一个单独的全局变量而不是对象属性。使用$this：

class app {
    public $conf = array();
    public function init(){
       $this->conf['theme']   = 'default';
       $this->conf['favicon'] = 'favicon.ico';
    }
    public function site_title(){
        return 'title';
    }
}
$app = new app;
$app->init();

//output
echo $app->conf['theme'];

Answer 2

你就在OOP的精彩世界里，不用再用了global！

试试这个：

class app
{
    public $conf = array();

    // Notice this method will be called every time the object is isntantiated
    // So you do not need to call init(), you can if you want, but this saves
    // you a step
    public function __construct()
    {       
        // If you are accessing any member attributes, you MUST use `$this` keyword
        $this->conf['theme']   = 'default';
        $this->conf['favicon'] = 'favicon.ico';
    }
}

$app = new app;

//output
echo $app->conf['theme'];