实际上，UIWebView自己是有缓存的，但容量有限，清理时间我们也不好掌握，那它是用什么做的缓存呢？是NSURLCache。看到它有几个方法:
+ (void)setSharedURLCache:(NSURLCache *)cache;
- (NSCachedURLResponse *)cachedResponseForRequest:(NSURLRequest *)request;
- (void)storeCachedResponse:(NSCachedURLResponse *)cachedResponse forRequest:(NSURLRequest*)request;
太好了，我们只要写一个子类继承NSURLCache，实现后两个方法，再让这个子类对象成为sharedURLCache，就可以操控webView的请求和缓存了。抛个砖吧：
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- (NSCachedURLResponse *)cachedResponseForRequest:(NSURLRequest *)request { NSString *pathString = [[request URL] absoluteString]; if (![pathString hasSuffix:@".jpg"]) { return [super cachedResponseForRequest:request]; } if ([[MYURLCache sharedCache] hasDataForURL:pathString]) { NSData *data = [[MYURLCache sharedCache] dataForURL:pathString]; NSURLResponse *response = [[[NSURLResponse alloc] initWithURL:[request URL] MIMEType:@"image/jpg" expectedContentLength:[data length] textEncodingName:nil] autorelease]; return [[[NSCachedURLResponse alloc] initWithResponse:response data:data] autorelease]; } return [super cachedResponseForRequest:request];} - (void)storeCachedResponse:(NSCachedURLResponse *)cachedResponse forRequest:(NSURLRequest *)request { NSString *pathString = [[request URL] absoluteString]; if (![pathString hasSuffix:@".jpg"]) { [super storeCachedResponse:cachedResponse forRequest:request]; return; } [[MYURLCache sharedCache] storeData:cachedResponse.data forURL:pathString];} |
上面的代码是专门用来搞定webView中的jpg图片的，其中MYURLCache提供了把data读、写入文件的功能，这个不是本文的重点，请各位自己实现吧。
在程序启动的时候，加入以下代码：
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MYURLCache *cache = [[MYURLCache alloc] init];[NSURLCache setSharedURLCache:cache]; |
OK，搞定了，试试webView加载图片吧~