旋转设备时保持CAEmitter居中

Question

旋转设备时，有没有办法让CAEmitter以UIView为中心（使用Autolayout）？

我将我的发射器添加到viewDidLoad，如下所示：

   // setup emitter
        let emitter = CAEmitterLayer()
        emitter.frame = self.view.bounds

        emitter.renderMode = kCAEmitterLayerAdditive
        emitter.emitterPosition = self.view.center
        self.view.layer.insertSublayer(emitter, atIndex: 1)

        // setup cells
        let cell = CAEmitterCell()
        cell.contents = UIImage(named: "particle")?.CGImage
        cell.birthRate = 1500
        cell.lifetime = 5.0
        cell.color = UIColor(red: 1.0, green: 0.5, blue: 0.1, alpha: 1).CGColor
        cell.alphaSpeed = -0.4
        cell.velocity = 50
        cell.velocityRange = 250

        cell.emissionRange = CGFloat(M_PI) * 2.0

        //add cells to the emitter
        emitter.emitterCells = [cell]

我试图删除它并重新添加它但它没有居中....

Answer 1

好吧，明白了。对于遇到这个的人......

 override func viewDidLayoutSubviews() {

      emitter.emitterPosition = self.view.center

     }