问题描述

每次我使用 UIWebView 加载新页面时，之前加载的页面都会显示一小段时间.

Every time I load a new page with UIWebView the before loaded page is shown for a short time.

如何清除该缓存?另一种可能性是释放 UIWebview.我试过了，但我的 UIWebView 总是空的".这种情况下alloc和dealloc应该怎么做呢?

How can I clear that cache? Another possibility would be to dealloc UIWebview. I tried that but than my UIWebView is always "empty". How should the alloc and dealloc be done in this case?

我注意到 UIWebView 消耗了大约 10 MB RAM.现在 UIWebView 与 ViewController 一起加载.并且视图是自动发布的，并且 UIWebView 是自动发布的.每次释放 WebView 不是更好吗?

I noticed that the UIWebView is consuming about 10 MB RAM. Now the UIWebView is loaded together with the ViewController. And the view is autoreleased as well as the UIWebView is autoreleased. Wouldn't it be better to dealloc the WebView each time?

解决方案:

- (void) viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];

    CGRect frame = CGRectMake(0, 0, 320, 480);
    self.webView = [[[UIWebView alloc]initWithFrame:frame] autorelease];
    self.webView.scalesPageToFit = YES;
    [self.view addSubview:self.webView];
}

- (void) viewDidDisappear:(BOOL)animated {
    [super viewDidDisappear:animated];

    [self.webView removeFromSuperview];
    self.webView = nil;
}

推荐答案

我对这个问题的解决方案是在 viewWillAppear: 上以编程方式创建 UIWebView 并在viewDidDisappear:，像这样:

My solution to this problem was to create the UIWebView programmatically on viewWillAppear: and to release it on viewDidDisappear:, like this:

- (void) viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];

    self.webView = [[[UIWebView alloc]initWithFrame:exampleFrame] autorelease];
    self.webView.scalesPageToFit = YES;
    self.webView.delegate = self;
    self.webView.autoresizingMask = webViewBed.autoresizingMask;
    [exampleView addSubview:self.webView];
}
- (void) viewDidDisappear:(BOOL)animated {
    [super viewDidDisappear:animated];

    [self.webView removeFromSuperview];
    self.webView.delegate = nil;
    self.webView = nil;
}

如果你这样做并且你的 UIWebView 没有被释放，你应该检查它的保留计数并了解谁在保留它.

If you do this and your UIWebView doesn't get released you should check it's retain count and understand who is retaining it.

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