首先要创建UIWebview, 然后直接添加长按手势如下:
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//创建长按手势对象, 并添加到webview上
UILongPressGestureRecognizer *longtapGesture = [[UILongPressGestureRecognizer alloc]initWithTarget:self action:@selector(longtap:)];
[webView addGestureRecognizer:longtapGesture];
长按事件:
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//长按下载图片
-(void)longtap:(UILongPressGestureRecognizer * )longtapGes {
if (longtapGes.state == UIGestureRecognizerStateBegan) {
//获取手势位置
CGPoint pt = [longtapGes locationInView:appFrame.webView];
pt = [appFrame.webView convertPoint:pt fromView:nil];
CGPoint offset = [appFrame.webView.scrollView contentOffset];
CGSize viewSize = [appFrame.webView frame].size;
CGSize windowSize = [appFrame.webView frame].size;
CGFloat f = windowSize.width / viewSize.width;
//如果不加判断,在webview滑动时将捕获不到image
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
pt.x = pt.x * f + offset.x;
pt.y = pt.y * f + offset.y;
}
[self openContextualMenuAt:pt];
}
}
根据获取到的手势位置,通过注入一段js方法最终获取到该位置上的图片:
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//根据长按位置获取当前图片
- (void)openContextualMenuAt:(CGPoint)pt {
//加载本地js, 也可以直接加载js字符串
NSString *path = [[NSBundle mainBundle] pathForResource:@"longPressJS" ofType:@"txt"];
NSString *jsCode = [NSString stringWithContentsOfFile:path encoding:NSUTF8StringEncoding error:nil];
[appFrame.webView stringByEvaluatingJavaScriptFromString: jsCode];
//获取图片标签
NSString *tags = [appFrame.webView stringByEvaluatingJavaScriptFromString:
[NSString stringWithFormat:@"MyAppGetHTMLElementsAtPoint(%f,%f);",pt.x,pt.y]];
UIActionSheet *sheet = [[UIActionSheet alloc] initWithTitle:@"保存图片到相册"
delegate:self cancelButtonTitle:@"取消"
destructiveButtonTitle:nil otherButtonTitles:nil];
//判断是否获取到图片
if ([tags rangeOfString:@",IMG,"].location != NSNotFound) {
NSString *str = [NSString stringWithFormat:@"document.elementFromPoint(%f, %f).src", pt.x, pt.y];
NSString *imgStr= [appFrame.webView stringByEvaluatingJavaScriptFromString: str];
_imgUrl = imgStr;
NSLog(@"imgUrl : %@",_imgUrl);
[sheet addButtonWithTitle:@"保存图片"];
[sheet showInView:self.view];
}
}
#pragma mark UIActionSheetDelegate
- (void)actionSheet:(UIActionSheet *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex {
NSLog(@"%li",buttonIndex);
if (buttonIndex == 1) {
NSLog(@"image url=%@", _imgUrl);
NSData *data = [NSData dataWithContentsOfURL:[NSURL URLWithString:_imgUrl]];
UIImage *image = [UIImage imageWithData:data];
//UIImageWriteToSavedPhotosAlbum(image, nil, nil,nil);
UIImageWriteToSavedPhotosAlbum(image, self, @selector(image:didFinishSavingWithError:contextInfo:), nil);
}
}
//保存图片
- (void)image:(UIImage *)image didFinishSavingWithError:(NSError*)error contextInfo:(void *)contextInfo {
if (error) {
NSLog(@"Error");
[MBProgressHUD showError:@"保存失败" toView:self.view];
}else {
NSLog(@"OK");
[MBProgressHUD showSuccess:@"保存成功" toView:self.view];
}
}
需要用到longPressJS.txt 里面是一段js代码, 新建一个空白文档将下面代码复制到文档中保存,直接拖入工程即可:
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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;
}
