renderInContext 多次崩溃应用程序

Question

我花了很多时间在谷歌搜索，但我没有得到好的结果。 我将 UIWebView 转换为 PDF，这是一个长 contentsize 的 webview（webview 中滚动的 ContentSize）。

我使用 RenderInContext 进行循环，但是当我使用 webview 转换时它会崩溃很长时间 请帮我用 20 页修复这个错误。

这是我的代码：

UIGraphicsBeginPDFContextToFile(documentDirectoryFilename, CGRectMake(0, 0, aWebView.scrollView.contentSize.width, screenHight), nil);
aWebView.scrollView.contentSize.width, screenHight), nil);

for (int i = 0; i < 20; i++) {

    @autoreleasepool {
        UIGraphicsBeginPDFPage();
        CGContextRef currentContext = UIGraphicsGetCurrentContext();
        [[[aWebView subviews] lastObject] setContentOffset:CGPointMake(0, screenHight * i) animated:NO];
        [aWebView.layer renderInContext:currentContext];
        currentContext = nil;
    }

}
UIGraphicsEndPDFContext();
aWebView.layer.contents = nil;

我使用了 autoReleasePool 并将结果保存到文件中。但它也会产生崩溃。

Answer 1

试试下面我测试过的对我来说很好用的代码……

 -(void)createPDFfromUIView:(UIWebView*)webView saveToDocumentsWithFileName:(NSString*)aFilename
    {
        NSString *heightStr = [webView stringByEvaluatingJavaScriptFromString:@"document.body.scrollHeight;"];

        int height = [heightStr intValue];
        //  CGRect screenRect = [[UIScreen mainScreen] bounds];
        //  CGFloat screenHeight = (self.contentWebView.hidden)?screenRect.size.width:screenRect.size.height;
        CGFloat screenHeight = webView.bounds.size.height;
        int pages = ceil(height / screenHeight);

        NSMutableData *pdfData = [NSMutableData data];
        UIGraphicsBeginPDFContextToData(pdfData, webView.bounds, nil);
        CGRect frame = [webView frame];
        for (int i = 0; i < pages; i++) {
            // Check to screenHeight if page draws more than the height of the UIWebView
            if ((i+1) * screenHeight  > height) {
                CGRect f = [webView frame];
                f.size.height -= (((i+1) * screenHeight) - height);
                [webView setFrame: f];
            }

            UIGraphicsBeginPDFPage();
            CGContextRef currentContext = UIGraphicsGetCurrentContext();
            //      CGContextTranslateCTM(currentContext, 72, 72); // Translate for 1" margins

            [[[webView subviews] lastObject] setContentOffset:CGPointMake(0, screenHeight * i) animated:NO];
            [webView.layer renderInContext:currentContext];
        }

        UIGraphicsEndPDFContext();
        // Retrieves the document directories from the iOS device
        NSArray* documentDirectories = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask,YES);

        NSString* documentDirectory = [documentDirectories objectAtIndex:0];
        NSString* documentDirectoryFilename = [documentDirectory stringByAppendingPathComponent:aFilename];

        // instructs the mutable data object to write its context to a file on disk
        [pdfData writeToFile:documentDirectoryFilename atomically:YES];
        [webView setFrame:frame];
    }