IOS Objective C 保存图像，通过按住在 Safari 中显示在 UIWebview 中答案

【问题标题】：IOS Objective C save image that is displayed in UIWebview by press and hold like in SafariIOS Objective C 保存图像，通过按住在 Safari 中显示在 UIWebview 中
【发布时间】：2017-05-18 15:37:49
【问题描述】：

我是IOS的初学者。我正在编写一个在 UIWebview 中显示网站的应用程序。现在我希望当用户按住图像时，他可以像在 safari 中一样保存图像。我的代码现在看起来像这样，但应用程序甚至无法识别按住手势：

    -(BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType{
if (navigationType == UIWebViewNavigationTypeLinkClicked) {
else if([request.URL.absoluteString containsString:@".png"]||[request.URL.absoluteString containsString:@".jpg"]){
            self.lpgr = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(handleLongPressGestures:)];

            self.lpgr.minimumPressDuration = 1.0f;
            self.lpgr.allowableMovement = 100.0f;
            self.lpgr.delegate = self;

            [self.webVIew addGestureRecognizer:self.lpgr];


        return false;
    }

    return TRUE;
}

- (void)handleLongPressGestures:(UILongPressGestureRecognizer *)sender
{
    NSLog(@"go within LongPressgesture methode");
    if ([sender isEqual:self.lpgr]) {
       if (sender.state == UIGestureRecognizerStateBegan)
       {
           NSLog(@"go within LongPressgesture methode2");

            UIMenuItem* myBtn1 = [[UIMenuItem alloc] initWithTitle: @"Speichern" action:@selector( onButton1: )];

            UIMenuController* mc = [UIMenuController sharedMenuController];
            mc.menuItems = [NSArray arrayWithObjects: myBtn1, nil];

                }


    }
    }
- (void) onButton1: (UIMenuController*) sender
{
    UIGraphicsBeginImageContext(self.webVIew.frame.size);
    [self.webVIew.layer renderInContext: UIGraphicsGetCurrentContext()];
    UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    UIImageWriteToSavedPhotosAlbum(viewImage, self, nil, nil);

}
 and in the header file:
@interface WebViewController : UIViewController<UIWebViewDelegate, UIGestureRecognizerDelegate>{
    IBOutlet UIButton *btnHome;

    BOOL isLoaded;
    ACAccountStore *account ;


}

我不知道我做错了什么。感谢您的每一个建议。

【问题讨论】：

标签： ios objective-c

【解决方案1】：

WebView 已经有一个手势识别器。因此需要实现UIGestureRecognizerDelegate 的方法- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer。否则，触摸只会发送到 Web 视图的手势识别器。

因此将以下方法添加到您的代码中：

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer {
    return YES;
}

将此协议添加到您的标头中：UIGestureRecognizerDelegate

并在创建手势识别器时添加以下行：

self.lpgr.delegate = self;

【讨论】：