Swift/iOS |如何启用 'press and hold' 以在 UIWebView 中保存图像？

Question

我正在编写一个应用程序可以从我的服务器加载文章列表和特定文章。我正在使用 UIWebView 加载文章内容（是一个 HTML 字符串）。现在的问题是，当用户按住 UIWebView 中的图像时，会跳出一个动作sheet 并给用户保存图像选项。

我尝试了这些，none 对我有用。

whosebug.com/questions/31673916/tap-and-hold-save-image-from-uiwebview

buzztouch.com/forum/thread.php?tid=7EF2CABD19B91FB8D9C20E6&currentPage=1

Answer 1

是的！！！！！！！我终于做到了！！！！通过使用 JavaScript 和 stringByEvaluatingJavaScriptFromString。

我在 github 上发布了我的答案：https://github.com/theniceboy/HoldToSaveImage

这是我的代码：

//
//  FrmArticle.swift
//  CenterBrain
//
//  Created by David Chen on 9/7/15.
//  Copyright © 2015 David Chen. All rights reserved.
//

import UIKit

class FrmArticle: UIViewController, UIWebViewDelegate {

    // MARK: - Outlets
    @IBOutlet weak var wvContent: UIWebView!

    // MARK: - Vars & Lets
    var article_id: Int = 1
    var article: Article = Article()

    let kTouchJavaScriptString: String = "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\";};"
    var _gesState: Int = 0
    /*
    _gesState: 
        GESTURE_STATE_NONE = 0,
        GESTURE_STATE_START = 1,
        GESTURE_STATE_MOVE = 2,
        GESTURE_STATE_END = 4
    */

    var _imgURL: String = "", _timer: NSTimer = NSTimer()

    func webView(webView: UIWebView, shouldStartLoadWithRequest _request: NSURLRequest, navigationType: UIWebViewNavigationType) -> Bool {
        if (_request.URL! == "about:blank") {
            return false
        }
        let requestString: String = (_request.URL?.absoluteString)!
        var components: [String] = requestString.componentsSeparatedByString(":")
        if (components.count > 1 && components[0] == "myweb") {
            if (components[1] == "touch") {
                if (components[2] == "start") {
                    _gesState = 1
                    print("touch start!")
                    let ptX: Float = Float(components[3])!
                    let ptY: Float = Float(components[4])!
                    print("touch point \(ptX), \(ptY)")
                    let js: String = "document.elementFromPoint(\(ptX), \(ptY)).tagName"
                    let tagName: String = wvContent.stringByEvaluatingJavaScriptFromString(js)!
                    _imgURL = ""
                    print(tagName)
                    if (tagName == "IMG") {
                        _imgURL = wvContent.stringByEvaluatingJavaScriptFromString("document.elementFromPoint(\(ptX), \(ptY)).src")!
                        _timer = NSTimer.scheduledTimerWithTimeInterval(1, target: self, selector: "handleLongTouch", userInfo: nil, repeats: false)
                    }
                } else {
                    if (components[2] == "move") {
                        self._gesState = 2
                        print("you are move")
                    } else {
                        if (components[2] == "end") {
                            _timer.invalidate()
                            self._timer = NSTimer()
                            self._gesState = 4
                            print("touch end")
                        }
                    }
                }
            }
            return false
        }
        return true
    }

    func handleLongTouch() {
        print(_imgURL)
        if (_gesState == 1) {
            print("YES!!! I DID IT!!!")
        }
    }

    // MARK: - Override functions
    override func viewDidLoad() {
        wvContent.delegate = self
        super.viewDidLoad()
        wvContent.loadHTMLString("<h2 align=\"center\">Title</h2><img src=\"http://cdn.sstatic.net/Whosebug/img/apple-touch-icon@2.png?v=ea71a5211a91&a\">", baseURL: nil)
    }

    // MARK: - UIWebView delegate
    func webViewDidFinishLoad(webView: UIWebView) {
        activityIndicator.stopAnimating()
        activityIndicator.hidden = true
        wvContent.stringByEvaluatingJavaScriptFromString(kTouchJavaScriptString)
    }
}

Swift/iOS |如何启用 'press and hold' 以在 UIWebView 中保存图像？

Swift/iOS | How to enable 'press and hold' to save image in a UIWebView?

iphone

uiwebview

ios

swift