Question

这是我的三页。

OOexamples.php：

function __autoload($class_name) {
    require_once 'includes/'.$class_name . '.php';
}

$ObjColl = new ObjectCollection();
$bike1 = new Bike("R1", 1000);
$ObjColl->addItem($bike1);
$bike2 = new Bike("R6", 600);
$ObjColl->addItem($bike2);
$bike3 = new Bike("Bandit", 1000);
$ObjColl->addItem($bike3);
$bike4 = new Bike("Trial", 600);
$ObjColl->addItem($bike4);

for($i = 0;$ObjColl->getItemCount();$i++){
$item = $ObjColl->getItem($i);
if ($item instanceof Bike) {
 print "Bike - ";
}

print $item;
}

ObjectCollection.php：

 class ObjectCollection  
{  
//This is an array to hold line items
    private $items_array ;

    private $itemCounter; //Count the number of items

    public function __construct() {
        //Create an array object to hold line items
        $this->items_array = array();
        $this->itemCounter=0; 
     }

    public function getItemCount(){
        return $this->itemCounter;
    }  



    public function addItem($item) {
       $this->itemCounter++;
       $this->items_array[] = $item;
    }

    public function getItem() {
        return $this-> Bike = $item;
}
}

我80％确定它与该功能有关＆＃34; getItem＆＃34;以上。该行＆＃34;返回$ this-＆gt; Bike = $ item;＆＃34;使我的页面变白，它永远不会停止加载？

Bike.php：

class Bike {
    private $name;
    private $model;
    private $cc;

    public function __construct($name,$model){
        $this->name = $name;
        $this->model = $model;
    }

    public function set_cc($cc) {
        $this->cc = $cc;

    }
    public function get_cc() {
        return $this->cc;
} 

}

为什么我的每个循环都没有打印出Bike对象？我知道它与OOexamples页面上的每个循环有关。请帮助它让我发疯。我是OO的初学者，所以很容易。我得到的错误是＆＃34;致命错误：无法访问第27行＆＃34;中包含/ ObjectCollection.php中的空属性;

Answer 1

for($i = 0;$ObjColl->getItemCount();$i++){

应该是：

for($i = 0;$i < $ObjColl->getItemCount();$i++){

否则你的循环永远不会退出，因为没有比较。

还有一个错误：

public function getItem() {
    return $this-> Bike = $item;
}

不确定这会做什么，但$this->Bike不存在，因为类ObjectCollection没有属性Bike。因此，假设您希望方法getItem按给定索引返回项目，它应该是：

public function getItem($index) {
    return $this->items_array[$index];
}

总之，这是您的计划的外观：

<强> OOExamples.php：

function __autoload($class_name) {
  require_once 'includes/'.$class_name . '.php';
}

$ObjColl = new ObjectCollection();
$bike1 = new Bike("R1", 1000);
$ObjColl->addItem($bike1);
$bike2 = new Bike("R6", 600);
$ObjColl->addItem($bike2);
$bike3 = new Bike("Bandit", 1000);
$ObjColl->addItem($bike3);
$bike4 = new Bike("Trial", 600);
$ObjColl->addItem($bike4);

for($i = 0;$i < ObjColl->getItemCount();$i++){
  $item = $ObjColl->getItem($i);
  if ($item instanceof Bike) {
    print "Bike - ";
  }

  print $item->getName();
}

<强> ObjectCollection.php：

class ObjectCollection  
{  
//This is an array to hold line items
  private $items_array ;

  private $itemCounter; //Count the number of items

  public function __construct() {
    //Create an array object to hold line items
    $this->items_array = array();
    $this->itemCounter=0; 
  }

  public function getItemCount(){
    return $this->itemCounter;
  }  

  public function addItem($item) {
     $this->itemCounter++;
     $this->items_array[] = $item;
  }

  public function getItem($index) {
    return $this->items_array[$index];
  }
}

<强> Bike.php：

class Bike {
  private $name;
  private $model;
  private $cc;

  public function __construct($name,$model){
      $this->name = $name;
      $this->model = $model;
  }

  public function setCC($cc) {
      $this->cc = $cc;

  }

  public function getCC() {
    return $this->cc;
  } 

  public function setName($name) {
    $this->name = name;
  }

  public function getName() {
    return $this->name;
  }

  public function setModel($model) {
    $this->model = model;
  }

  public function getModel() {
    return $this->model;
  }

}

我的OO课程集合不起作用？

1 个答案: