第一步：在加载完成的代理方法里注入js代码
-(void)webViewDidFinishLoad:(UIWebView *)webView
{
// 注入js代码
static NSString* const kTouchJavaScriptString=
@"document.ontouchstart=function(event){
x=event.targetTouches[0].clientX;
y=event.targetTouches[0].clientY;
document.location="myweb:touch:start:"+x+":"+y;};
document.ontouchmove=function(event){
x=event.targetTouches[0].clientX;
y=event.targetTouches[0].clientY;
document.location="myweb:touch:move:"+x+":"+y;};
document.ontouchcancel=function(event){
document.location="myweb:touch:cancel";};
document.ontouchend=function(event){
document.location="myweb:touch:end";};";
[self.myWebView stringByEvaluatingJavaScriptFromString:kTouchJavaScriptString];
}
第二步：在点击网页开始请求的代理方法里做出判断，并添加处理弹出提示与实现下载功能
- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType{
NSString *requestString = [[request URL] absoluteString];
NSArray *components = [requestString componentsSeparatedByString:@":"];
if ([components count] > 1 && [(NSString *)[components objectAtIndex:0]
isEqualToString:@"myweb"]) {
if([(NSString *)[components objectAtIndex:1] isEqualToString:@"touch"])
{
//NSLog(@"you are touching!");
//NSTimeInterval delaytime = Delaytime;
if ([(NSString *)[components objectAtIndex:2] isEqualToString:@"start"])
{
/*
@需延时判断是否响应页面内的js...
*/
isTouch = YES;
NSLog(@"touch start!");
float ptX = [[components objectAtIndex:3]floatValue];
float ptY = [[components objectAtIndex:4]floatValue];
NSLog(@"touch point (%f, %f)", ptX, ptY);
NSString *js = [NSString stringWithFormat:@"document.elementFromPoint(%f, %f).tagName", ptX, ptY];
NSString * tagName = [self.myWebView stringByEvaluatingJavaScriptFromString:js];
_imgURL = nil;
if ([tagName isEqualToString:@"IMG"]) {
_imgURL = [NSString stringWithFormat:@"document.elementFromPoint(%f, %f).src", ptX, ptY];
}
if (_imgURL) {
_timer = [NSTimer scheduledTimerWithTimeInterval:2 target:self selector:@selector(handleLongTouch) userInfo:nil repeats:NO];
}
}
else if ([(NSString *)[components objectAtIndex:2] isEqualToString:@"move"])
{
//**如果touch动作是滑动，则取消hanleLongTouch动作**//
[_timer invalidate];
_timer = nil;
isTouch = NO;
NSLog(@"you are move");
}
}
else if ([(NSString*)[components objectAtIndex:2]isEqualToString:@"end"]) {
[_timer invalidate];
_timer = nil;
isTouch = NO;
NSLog(@"touch end");
}
return NO;
}
return YES;
}
- (void)handleLongTouch {
NSLog(@"%@", _imgURL);
if (_imgURL && isTouch) {
UIActionSheet* sheet = [[UIActionSheet alloc]initWithTitle:nil delegate:self cancelButtonTitle:@"取消" destructiveButtonTitle:nil otherButtonTitles:@"保存图片", nil];
sheet.cancelButtonIndex = sheet.numberOfButtons - 1;
[sheet showInView:self.view];
}
}
- (void)actionSheet:(UIActionSheet *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex {
if (actionSheet.numberOfButtons - 1 == buttonIndex) {
return;
}
NSString* title = [actionSheet buttonTitleAtIndex:buttonIndex];
if ([title isEqualToString:@"保存图片"]) {
if (_imgURL) {
NSLog(@"imgurl = %@", _imgURL);
}
_hud = [MBProgressHUD showHUDAddedTo:self.view animated:YES];
_hud.mode = MBProgressHUDModeIndeterminate;
_hud.delegate = self;
_hud.labelText = @"正在下载";
NSString *urlToSave = [self.myWebView stringByEvaluatingJavaScriptFromString:_imgURL];
NSLog(@"image url=%@", urlToSave);
NSData* data = [NSData dataWithContentsOfURL:[NSURL URLWithString:urlToSave]];
UIImage* image = [UIImage imageWithData:data];
//UIImageWriteToSavedPhotosAlbum(image, nil, nil,nil);
UIImageWriteToSavedPhotosAlbum(image, self, @selector(image:didFinishSavingWithError:contextInfo:), nil);
}
}
- (void)image:(UIImage *)image didFinishSavingWithError:(NSError*)error contextInfo:(void*)contextInfo
{
_hud.mode = MBProgressHUDModeText;
if (error){
NSLog(@"Error");
_hud.labelText = @"下载错误,请重试。";
}else {
NSLog(@"OK");
_hud.labelText = @"成功保存到相册";
[_hud hide:YES afterDelay:0.5f];
}
}