Ios 在何处/如何手动处理WKWebView estimatedProgress的观察者

我一直在尝试在Xamarin ios UIViewController中的“estimatedProgress”属性上使用KVO跟踪WKWebView上的估计加载进度

我添加了这样一个观察者：

public override void ViewDidLoad()
{
    base.ViewDidLoad();
    ...
    WkView.AddObserver("estimatedProgress", NSKeyValueObservingOptions.New, ProgressObserver);
    ...
}

public void ProgressObserver(NSObservedChange nsObservedChange)
{
    Console.WriteLine("Progress {0}", WkView.EstimatedProgress);
}

2015-11-17 09:29:15.345 testappiOS[10056:1381155] Progress 0.1
2015-11-17 09:29:15.636 testappiOS[10056:1381155] Progress 0.285892975242258
2015-11-17 09:29:15.949 testappiOS[10056:1381169] Warning: observer object was not disposed manually with Dispose()

ProgressObserver如下所示：

public override void ViewDidLoad()
{
    base.ViewDidLoad();
    ...
    WkView.AddObserver("estimatedProgress", NSKeyValueObservingOptions.New, ProgressObserver);
    ...
}

public void ProgressObserver(NSObservedChange nsObservedChange)
{
    Console.WriteLine("Progress {0}", WkView.EstimatedProgress);
}

2015-11-17 09:29:15.345 testappiOS[10056:1381155] Progress 0.1
2015-11-17 09:29:15.636 testappiOS[10056:1381155] Progress 0.285892975242258
2015-11-17 09:29:15.949 testappiOS[10056:1381169] Warning: observer object was not disposed manually with Dispose()

当我运行它时，它会返回如下内容：

public override void ViewDidLoad()
{
    base.ViewDidLoad();
    ...
    WkView.AddObserver("estimatedProgress", NSKeyValueObservingOptions.New, ProgressObserver);
    ...
}

public void ProgressObserver(NSObservedChange nsObservedChange)
{
    Console.WriteLine("Progress {0}", WkView.EstimatedProgress);
}

2015-11-17 09:29:15.345 testappiOS[10056:1381155] Progress 0.1
2015-11-17 09:29:15.636 testappiOS[10056:1381155] Progress 0.285892975242258
2015-11-17 09:29:15.949 testappiOS[10056:1381169] Warning: observer object was not disposed manually with Dispose()

显然，谷歌搜索“”会返回有关需要手动处理观察者的信息。但是我还没有弄明白如何把这个应用到我的问题上

---

有人能对此提供一些见解吗？

首先，您需要创建一个私有变量来保存一次性观察者：

private IDisposable progressObserver;

然后从AddObserver返回值中分配它，但将其放在视图将显示的方法中：

this.progressObserver = webView.AddObserver(
    "estimatedProgress", 
    NSKeyValueObservingOptions.New, 
    ProgressObserver);

在视图中处理它将消失：

this.progressObserver.Dispose();