UIWebView长按图片生成保存菜单

转载自:  http://zl4393753.iteye.com/blog/1752135

UIWebView长按图片生成保存菜单 
参考： 
http://www.icab.de/blog/2010/07/11/customize-the-contextual-menu-of-uiwebview/ 
http://www.icab.de/blog/2011/10/17/elementfrompoint-under-ios-5/comment-page-1/#comment-30184 

自定义UILongPressGestureRecognizer 
创建 UnpreventableUILongPressGestureRecognizer.h 

 #import
 @interface UnpreventableUILongPressGestureRecognizer : UILongPressGestureRecognizer {
 }
 @end

UnpreventableUILongPressGestureRecognizer.m 

 #import "UnpreventableUILongPressGestureRecognizer.h"

 @implementation UnpreventableUILongPressGestureRecognizer
 - (BOOL)canBePreventedByGestureRecognizer:(UIGestureRecognizer *)preventedGestureRecognizer {
     return NO;
 }
 @end

UIWebview页面给webview添加手势 ViewController.m： 

 UnpreventableUILongPressGestureRecognizer *longPressRecognizer = [[UnpreventableUILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(handleLongPress:)];
 longPressRecognizer.allowableMovement = 20;
 longPressRecognizer.minimumPressDuration = 1.0f;
 [webview addGestureRecognizer:longPressRecognizer];

ViewController.m 处理手势： 

 -(void)handleLongPress:(UILongPressGestureRecognizer *)gestureRecognizer
 {
     if (gestureRecognizer.state == UIGestureRecognizerStateBegan) {

         CGPoint pt = [gestureRecognizer locationInView:self.webview];

         // convert point from view to HTML coordinate system
         // 뷰의 포인트 위치를 HTML 좌표계로 변경한다.
         CGSize viewSize = [webview frame].size;
         CGSize windowSize = [webview windowSize];
         CGFloat f = windowSize.width / viewSize.width;

         if ([[[UIDevice currentDevice] systemVersion] doubleValue] >= 5.0) {
             pt.x = pt.x * f;
             pt.y = pt.y * f;
         } else {
             // On iOS 4 and previous, document.elementFromPoint is not taking
             // offset into account, we have to handle it
             CGPoint offset = [webview scrollOffset];
             pt.x = pt.x * f + offset.x;
             pt.y = pt.y * f + offset.y;
         }

         [self openContextualMenuAt:pt];
     }
 }

创建分类 WebViewAdditions.h 

 #import
 @interface UIWebView(WebViewAdditions)
 - (CGSize)windowSize;
 - (CGPoint)scrollOffset;
 @end

WebViewAdditions.m 

 #import "WebViewAdditions.h"

 @implementation UIWebView(WebViewAdditions)

 - (CGSize)windowSize
 {
     CGSize size;
     size.width = [[self stringByEvaluatingJavaScriptFromString:@"window.innerWidth"] integerValue];
     size.height = [[self stringByEvaluatingJavaScriptFromString:@"window.innerHeight"] integerValue];
     return size;
 }

 - (CGPoint)scrollOffset
 {
     CGPoint pt;
     pt.x = [[self stringByEvaluatingJavaScriptFromString:@"window.pageXOffset"] integerValue];
     pt.y = [[self stringByEvaluatingJavaScriptFromString:@"window.pageYOffset"] integerValue];
     return pt;
 }
 @end

弹出菜单 ViewController.m 

 - (void)openContextualMenuAt:(CGPoint)pt{
     // Load the JavaScript code from the Resources and inject it into the web page
     NSBundle *bundle = [NSBundle bundleWithPath:[[NSBundle mainBundle] pathForResource:@"Naving" ofType:@"bundle"]];
     NSString *path = [bundle pathForResource:@"JSTools" ofType:@"js"];
     NSString *jsCode = [NSString stringWithContentsOfFile:path encoding:NSUTF8StringEncoding error:nil];
     [webview stringByEvaluatingJavaScriptFromString:jsCode];

     // get the Tags at the touch location
     NSString *tags = [webview stringByEvaluatingJavaScriptFromString:
                       [NSString stringWithFormat:@"MyAppGetHTMLElementsAtPoint(%i,%i);",(NSInteger)pt.x,(NSInteger)pt.y]];

     NSString *tagsHREF = [webview stringByEvaluatingJavaScriptFromString:
                           [NSString stringWithFormat:@"MyAppGetLinkHREFAtPoint(%i,%i);",(NSInteger)pt.x,(NSInteger)pt.y]];

     NSString *tagsSRC = [webview stringByEvaluatingJavaScriptFromString:
                          [NSString stringWithFormat:@"MyAppGetLinkSRCAtPoint(%i,%i);",(NSInteger)pt.x,(NSInteger)pt.y]];

     NSLog(@"tags : %@",tags);
     NSLog(@"href : %@",tagsHREF);
     NSLog(@"src : %@",tagsSRC);

     if (!_actionActionSheet) {
         _actionActionSheet = nil;
     }
     _actionActionSheet = [[UIActionSheet alloc] initWithTitle:nil
                                                        delegate:self
                                               cancelButtonTitle:nil
                                          destructiveButtonTitle:nil
                                               otherButtonTitles:nil];

     selectedLinkURL = @"";
     selectedImageURL = @"";

     // If an image was touched, add image-related buttons.
     if ([tags rangeOfString:@",IMG,"].location != NSNotFound) {
         selectedImageURL = tagsSRC;

         if (_actionActionSheet.title == nil) {
             _actionActionSheet.title = tagsSRC;
         }

         [_actionActionSheet addButtonWithTitle:@"Save Image"];
         [_actionActionSheet addButtonWithTitle:@"Copy Image"];
     }
     // If a link is pressed add image buttons.
     if ([tags rangeOfString:@",A,"].location != NSNotFound){
         selectedLinkURL = tagsHREF;

         _actionActionSheet.title = tagsHREF;
         [_actionActionSheet addButtonWithTitle:@"Open Link"];
         [_actionActionSheet addButtonWithTitle:@"Copy Link"];
     }

     if (_actionActionSheet.numberOfButtons > 0) {
         [_actionActionSheet addButtonWithTitle:@"Cancel"];
         _actionActionSheet.cancelButtonIndex = (_actionActionSheet.numberOfButtons-1);


         [_actionActionSheet showInView:webview];
     }

 }

工具文件 JSTools.js 

 function MyAppGetHTMLElementsAtPoint(x,y) {
     var tags = ",";
     var e = document.elementFromPoint(x,y);
     while (e) {
         if (e.tagName) {
             tags += e.tagName + ',';
         }
         e = e.parentNode;
     }
     return tags;
 }

 function MyAppGetLinkSRCAtPoint(x,y) {
     var tags = "";
     var e = document.elementFromPoint(x,y);
     while (e) {
         if (e.src) {
             tags += e.src;
             break;
         }
         e = e.parentNode;
     }
     return tags;
 }

 function MyAppGetLinkHREFAtPoint(x,y) {
     var tags = "";
     var e = document.elementFromPoint(x,y);
     while (e) {
         if (e.href) {
             tags += e.href;
             break;
         }
         e = e.parentNode;
     }
     return tags;
 }

ViewController.m 处理ActionSheet事件 

 #pragma UIActionSheetDelegate
 -(void)actionSheet:(UIActionSheet *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex{
     if ([[actionSheet buttonTitleAtIndex:buttonIndex] isEqualToString:@"Open Link"]){
         [webview loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:selectedLinkURL]]];
     }
     else if ([[actionSheet buttonTitleAtIndex:buttonIndex] isEqualToString:@"Copy Link"]){
         [[UIPasteboard generalPasteboard] setString:selectedLinkURL];
     }
     else if ([[actionSheet buttonTitleAtIndex:buttonIndex] isEqualToString:@"Copy Image"]){
         [[UIPasteboard generalPasteboard] setString:selectedImageURL];
     }
     else if ([[actionSheet buttonTitleAtIndex:buttonIndex] isEqualToString:@"Save Image"]){
         NSOperationQueue *queue = [NSOperationQueue new];
         NSInvocationOperation *operation = [[NSInvocationOperation alloc] initWithTarget:self
                                                                                 selector:@selector(saveImageURL:) object:selectedImageURL];
         [queue addOperation:operation];
         //[operation release];
     }
 }

 -(void)saveImageURL:(NSString*)url{
     [self performSelectorOnMainThread:@selector(showStartSaveAlert)
                            withObject:nil
                         waitUntilDone:YES];

     UIImageWriteToSavedPhotosAlbum([UIImage imageWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:url]]], nil, nil, nil);

     [self performSelectorOnMainThread:@selector(showFinishedSaveAlert)
                            withObject:nil
                         waitUntilDone:YES];
 }