小编Jus*_*ath的帖子

我有一个简单的代码来获取越南网站的响应:http://vnexpress.net,但是有一个小问题.这是第一次,它下载确定,但在此之后,内容包含这样的未知符号:\b\0\0\0\0\0 \0 \a`I %&/ m ....问题是什么？

    string address = "http://vnexpress.net";
    WebClient webClient = new WebClient();
    webClient.Headers.Add("user-agent", "Mozilla/5.0 (Windows NT 6.2; WOW64) AppleWebKit/537.11 (KHTML, like Gecko) Chrome/23.0.1271.97 Safari/537.11 AlexaToolbar/alxg-3.1");
    webClient.Encoding = System.Text.Encoding.UTF8;
    return webClient.DownloadString(address);

我有这个循环,在Swift 2中按分区递减整数.

for var i = 128; i >= 1 ; i = i/2  {
   //do some thing
}

不推荐使用C风格的for循环,那么如何将其转换为Swift 3.0呢？

我使用此代码从摄像机捕获视频，但是CMSampleBufferGetImageBuffer（sampleBuffer）始终返回nil。问题是什么？。这是代码，我修改了源代码以适应Swift 4 https://github.com/FlexMonkey/CoreImageHelpers/blob/master/CoreImageHelpers/coreImageHelpers/CameraCaptureHelper.swift

import AVFoundation
import CoreMedia
import CoreImage
import UIKit


class CameraCaptureHelper: NSObject
{
let captureSession = AVCaptureSession()
let cameraPosition: AVCaptureDevice.Position

weak var delegate: CameraCaptureHelperDelegate?

required init(cameraPosition: AVCaptureDevice.Position)
{
    self.cameraPosition = cameraPosition

    super.init()

    initialiseCaptureSession()
}

fileprivate func initialiseCaptureSession()
{
    captureSession.sessionPreset = AVCaptureSession.Preset.photo

    guard let camera = AVCaptureDevice.default(.builtInWideAngleCamera,
                                               for: .video, position: cameraPosition)
        else {
            fatalError("Unable to access camera")
    }
    do
    {
        let input = try AVCaptureDeviceInput(device: camera)

        captureSession.addInput(input)
    }
    catch
    {
        fatalError("Unable to access back camera")
    }

    let videoOutput = …