C++ WeakPtr::expired方法代码示例

		/*=============================================================================
		-- Sets the caption of the text in the middle.
		=============================================================================*/
		void ButtonCaption::SetCaption(String caption)
		{
			mCaption = caption;
			WeakPtr<Text> text = DynamicPtrCast<Text>(GetChild(IEI_BUTTONCAPTION_TEXT).lock());

			if (!text.expired())
			{
				text.lock()->SetText(caption);
				Font *font = text.lock()->GetFont();

				unsigned width = (unsigned)font->GetTextLengthPx(mCaption.GetStd());
				unsigned height = (unsigned)font->GetCharHeightPx();


				//clip any characters that don't fit inside from the text element
				while (width > GetWidth())
				{
					mCaption.Remove(mCaption.Size()-1,mCaption.Size());
					SetCaption(mCaption);
					width = (unsigned)font->GetTextLengthPx(mCaption.GetStd());
				}

				//properly center the text
				text.lock()->SetRelPos( Vector2D<int>((GetWidth()-width)/2, (GetHeight()-height)/2) );
			}
		}

		/*=============================================================================
		-- Adds the object to the inventory. Effectively "picking up" the object.
		=============================================================================*/
		void Actor::HoldObject(WeakPtr<Object> object)
		{
			if (!object.expired())
			{
				mInventory->AddObject(object);
				object.lock()->SetHost( GetManager()->GetEntity(GetId()) );
			}
		}

		/*=============================================================================
		-- Drops the object with the id in the inventory if it exists.
		=============================================================================*/
		void Actor::DropObject(int id)
		{
			//place the object on the ground behind the Actor so it does not walk over it right away.
			WeakPtr<Object> object = mInventory->GetObject(id);

			if (!object.expired())
			{
				object.lock()->SetHeld(false);
				object.lock()->SetPos(Vector3D<double>(GetPos().x+32.0, GetPos().y+32.0, GetPos().z+2.0));
				mInventory->RemoveObject(id);
			}
		}

		/*=============================================================================
		-- Special actions for colliding with certain enity types.
		=============================================================================*/
		void Actor::ReactToCollision(WeakPtr<Entity> entity)
		{
			if (entity.expired())
				return;

			if (entity.lock()->GetType() == OBJECT)
			{
				WeakPtr<Object> object = WeakPtr<Object>(DynamicPtrCast<Object>(entity.lock()));

				if (object.lock()->GetObtainable())
					HoldObject( object );
			}
		}

 bool operator()(const WeakPtr &wp) const
 {
   return wp.expired();
 }