小编Had*_*ier的帖子

我有一个"用户"表,这里有一个示例:

{
    username:"haddox",
    formattedPhoneNumber:"676767676",
    verified: 0,
}

我的愿望是检索formatPhoneNumber包含在电话号码数组中的所有用户(从我的联系人中检索).我创建了一个二级索引,验证为HASH,formattedPhoneNumber为RANGE.这是我的尝试:

var params = {
    TableName: "Users",
    IndexName: "FormattedPhoneSecondaryIndex",
    KeyConditionExpression: "verified  = :v AND formattedPhone IN :n",
    ExpressionAttributeValues: {
        ":v":1,
        ":n": ["672053916", "642117296"]
    },
    ProjectionExpression: "username, formattedPhoneNumber"
};



dynamodb.query(params, function(err, data) {
    if (err)
        console.log(JSON.stringify(err, null, 2));
    else
        console.log(JSON.stringify(data, null, 2));
});

但是我收到以下错误: Invalid KeyConditionExpression: Syntax error; token: \":n\", near: \"IN :n\"",

IN关键字有问题吗？也许有另一种方法来实现这一目标？

我正在玩ARKit,我想从ARSKView帧创建一个视频.我尝试使用ReplayKit,但行为不是我所期望的: - 我不想记录整个屏幕. - 我不希望提示用户我们正在录制屏幕.

另外,我如何结合微输入和视频？我想在ARSKView中没有流式传输音频？这是代码(来自Apple示例):

import UIKit
import SpriteKit
import ARKit

class ViewController: UIViewController, ARSKViewDelegate {

    @IBOutlet var sceneView: ARSKView!

    override func viewDidLoad() {
        super.viewDidLoad()
        // Set the view's delegate
        sceneView.delegate = self

        // Show statistics such as fps and node count
        sceneView.showsFPS = true
        sceneView.showsNodeCount = true

        // Load the SKScene from 'Scene.sks'
        if let scene = SKScene(fileNamed: "Scene") {
            sceneView.presentScene(scene)
        }
    }

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)

        // Create a session configuration
        let configuration = …

我正在尝试像摄像机视图一样做一个像摄像机视图,相机流填充所有屏幕.

这是代码:

func beginSession() {
    var err : NSError? = nil

    // try to open the device
    let videoCapture = AVCaptureDeviceInput(device: captureDevice, error: &err)

    if err != nil {
        // Fail silently.  Do better in the real world.
        println("Capture session could not start: \(err?.description)")
        return
    }

    // add video input
    if captureSession.canAddInput(videoCapture) {
        captureSession.addInput(videoCapture)
    }

    // config capture session
    if !captureSession.running {
        // set JPEG output
        stillImageOutput = AVCaptureStillImageOutput()
        let outputSettings = [ AVVideoCodecKey : AVVideoCodecJPEG ]
        stillImageOutput!.outputSettings = outputSettings …