UIWebView长按图片生成保存菜单

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 <Foundation/Foundation.h>
@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 <foundation foundation.h="">
@interface UIWebView(WebViewAdditions)
- (CGSize)windowSize;
- (CGPoint)scrollOffset;
@end
</foundation>

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];
}