Question

我正在开发一个使用swift通过蓝牙与设备通信的iPhone应用程序。首先，我有一个bluetoothViewController（）接收数据和SingleAxisViewController（）来显示和动画收到的数据。以下是我目前的代码

BluetoothViewController

import UIKit
import CoreBluetooth
import Foundation

class BluetoothViewController: UIViewController, CBCentralManagerDelegate,CBPeripheralDelegate,UITableViewDelegate,UITableViewDataSource,ValueChangedDelegate {

struct DataReceived {
    static var Parameter_1: Double = 90
}
      .
      .
      .
func peripheral(peripheral: CBPeripheral!, didUpdateValueForCharacteristic characteristic: CBCharacteristic!, error: NSError!) {

var hashedData = characteristic.value

//Conversion hashedData into Double type

DataReceived.Parameter_1 = Double(hashedData)

let singleaxisview = SingeAxisViewController()
singleaxisview.delegate = self
singleaxisview.valueChangedNotifyEveryone()
}

func valueChanged(nValue : String)
{
    println("do nothing")
    print(nValue)
}

Parameter1ViewController

import UIKit
import CoreGraphics

protocol ValueChangedDelegate
{
   func valueChanged(nValue : String)
}

class SingeAxisViewController: UIViewController {
var delegate : ValueChangedDelegate?
@IBOutlet weak var Needle: UIImageView!

override func viewDidLoad() {
    super.viewDidLoad()
    setAnchorPoint()
    var image: UIImage = UIImage(named: "arrow")!
    Needle = UIImageView(image: image)
}

func valueChangedNotifyEveryone()
{
        angle = BluetoothViewController.DataReceived.Parameter_1
        var image: UIImage = UIImage(named: "arrow")!
        Needle = UIImageView(image: image)
        Needle.transform = CGAffineTransformMakeRotation((CGFloat(angle*14.2) * CGFloat(M_PI) / 180.0))              
        }

func setAnchorPoint() {
        angle = BluetoothViewController.DataReceived.Parameter_1
        Needle.transform = CGAffineTransformMakeRotation((CGFloat(angle*14.2) * CGFloat(M_PI) / 180.0))
     }

所以我的问题是当我进入Parameter1ViewController时，图像可以旋转并起作用。但是当蓝牙值改变时，函数valueChangedNotifyEveryone()被触发并发生错误：

在展开“可选”值时发现nil

在

 Needle.transform = CGAffineTransformMakeRotation((CGFloat(angle*14.2) * CGFloat(M_PI) / 180.0))

有人能说明原因吗？

从其他视图控制器以编程方式旋转图像

0 个答案: