小编Aru*_*n K的帖子

我是反应原生开发的新手。我希望图像具有纵横比，当我尝试更改其边界时，应剪掉边界之外的区域。在 Android 中，它工作正常，但在 iOS 中则不然，图像不会剪切到其边界并显示整个图像。

<View
      style={{
        backgroundColor: "#04894a",
        padding: 10,
        height: 110,
        alignItems: "center"
      }}
    >
 <View
        style={{
          alignItems: "center"
        }}
      >
        <Image
          style={{ height: 150, width: 150 }}
          source={require("../images/wow_logo.png")}
        />
      </View>

图像超出了视图范围，但仍然完整显示。如果超出范围，我希望将其裁剪。谁能帮我这个？任何链接或建议也将受到赞赏。TIA

我正在使用此代码来呈现 UIActivityViewController。

 var a = standard.value(forKey: "first_name") as? String
    let text = a! + " text to share"
    let url : NSURL = NSURL(fileURLWithPath: "https://itunes.apple.com/in/app/")

    let textToShare = [ text as String , url as URL ] as [Any]
    let activityViewController = UIActivityViewController(activityItems: textToShare, applicationActivities: nil)


    activityViewController.popoverPresentationController?.sourceView = self.view // so that iPads won't crash
    activityViewController.completionWithItemsHandler = {
        (s, ok, items, error) in
        if ok == true {
            DispatchQueue.main.async {
               // code after completion
            }

        }
    }
    self.present(activityViewController, animated: true, …

我在appDelegate中编写了这段代码

import UserNotifications
var registerId = String()
func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
    self.registerForPushNotifications(application)
    return true   
}

func application(application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: NSData) {
    let tokenChars = UnsafePointer<CChar>(deviceToken.bytes)
    var tokenString = ""
    for i in 0..<deviceToken.length {
        tokenString += String(format: "%02.2hhx", arguments: [tokenChars[i]])
    }
    registerId = tokenString
}
func application(application: UIApplication, didRegisterUserNotificationSettings notificationSettings: UIUserNotificationSettings) {
    if notificationSettings.types != .None {
        application.registerForRemoteNotifications()
    }
}
func registerForPushNotifications(application: UIApplication) {

    if #available(iOS 10.0, *){
        UNUserNotificationCenter.currentNotificationCenter().delegate = self
        UNUserNotificationCenter.currentNotificationCenter().requestAuthorizationWithOptions([.Badge, .Sound, …

我从 AVAudioRecorder.peakPowerForChannel(0) 获取从 -70 到 10 左右的幅度值。我需要 0 到 120 范围内的值，我是如何做到的。我需要从整个音频中获得最高的振幅值。在互联网上看到这段代码

var numver = 20 * log10(audioRecorder.peakPowerForChannel(0))

但这给出了一个值 nan（不是数字）。我怎样才能获得正范围内的振幅值。

我需要从一个浮点数数组中获得2个最大值，即一个最高和一秒钟的最高值。是否有任何简单的方法来获取它们的索引，或者是否需要为此更改数组的结构？