>用户将看到一个带有UIWebView的屏幕
> UIViewController在委托网页开始下载时设置self
>用户退出屏幕
> UIViewController获取解除分配UIWebView完成加载并发送我已完成加载消息到其委托

要么

当webview对象不再是.i.e悬挂指针效果时,会调用其他一些委托方法

1.始终确保在离开视图之前停止加载webView并删除委托

Before releasing an instance of UIWebView for which you have set a
delegate,you must first set its delegate property to nil. This can
be done,in your dealloc method

这是reference

// If ARC is used
- (void)dealloc {
    [_webView setDelegate:nil];
    [_webView stopLoading];
}

// If ARC is not used
- (void)dealloc {
    [webView setDelegate:nil];
    [webView stopLoading];
    [webView release];
    [super dealloc];
}

// ARC - Before iOS6 as its deprecated from it.
- (void)viewWillUnload {
    [webView setDelegate:nil];
    [webView stopLoading];
}

2.确保你在viewWillDisappear中没有stopLoading和setDelegate为nil

if the ViewController is a child of a another ViewController,u can
trigger the removal of the ViewController’s view from the parent
ViewController’s view with an animation. At the same time,u can
remove the ViewController from its parent and nil out its reference.
at this point ViewController will be nil and viewWillDisappear
will never be called,meaning the WebView delegate will never be
cleaned up

Use dealloc and ensure that your WebView is always cleaned up.

3.确保在没有动画的情况下将webview子视图的ContentOffset设置为CGPointZero

In iPad in some versions while webview is scrolling if you close the parent
viewcontroller without setting ContentOffset to CGPointZero this
kind of problems will come

所以最好在关闭它之前调用父视图控制器中的以下代码

for (id subview in webView.subviews){
        if ([[subview class] isSubclassOfClass: [UIScrollView class]]){
            [subview setContentOffset:CGPointZero animated:NO];
        }
    }

希望这会有所帮助.随意问你的疑惑.

4.一般来说,您不应该在UIS​​crollView对象中嵌入UIWebView对象.如果这样做,可能会导致意外行为,因为两个对象的触摸事件可能混淆和错误处理.

这是reference