ios - Find text in webview page using swift?

Question

How can I find text in uiwebview page and highlight it and go to its position in the page using swift ?

For example chrome find text :

search example

But I'm using alert view instead :

my search example in my app !!!

Answer 1

You have to use JavaScript for this.
I done the same thing with code below (but in Objective C - you can rewrite it to Swift).

Usage (only in webViewDidFinishLoad - it's important!):

-(void)webViewDidFinishLoad:(UIWebView *)webView {
    if (self.searchString != nil ) {
        [self.webView highlightAllOccurencesOfString:self.searchString];
        int position = self.foundedStringsCount - self.selectedStringNumber - 1;
        [self.webView scrollTo:position];
    }
}

Create and add this files to your code:

SearchWebView.h:

#import <Foundation/Foundation.h>

@interface SearchWebView : UIWebView

- (NSInteger)highlightAllOccurencesOfString:(NSString*)str;
- (void)scrollTo:(int)index;
- (void)removeAllHighlights;

@end

SearchWebView.m:

#import "SearchWebView.h"

@implementation SearchWebView

- (NSInteger)highlightAllOccurencesOfString:(NSString*)str
{
    NSString *path = [[NSBundle mainBundle] pathForResource:@"UIWebViewSearch" ofType:@"js"];
    NSString *jsCode = [NSString stringWithContentsOfFile:path encoding:NSUTF8StringEncoding error:nil];
    [self stringByEvaluatingJavaScriptFromString:jsCode];

    NSString *startSearch = [NSString stringWithFormat:@"uiWebview_HighlightAllOccurencesOfString('%@')",str];
    [self stringByEvaluatingJavaScriptFromString:startSearch];

    NSString *result = [self stringByEvaluatingJavaScriptFromString:@"uiWebview_SearchResultCount"];
    return [result integerValue];
}

- (void)scrollTo:(int)index {
    [self stringByEvaluatingJavaScriptFromString:[NSString stringWithFormat:@"uiWebview_ScrollTo('%d')",index]];
}

- (void)removeAllHighlights
{
    [self stringByEvaluatingJavaScriptFromString:@"uiWebview_RemoveAllHighlights()"];
}

@end

UIWebViewSearch.js:

var uiWebview_SearchResultCount = 0;

/*!
 @method     uiWebview_HighlightAllOccurencesOfStringForElement
 @abstract   // helper function, recursively searches in elements and their child nodes
 @discussion // helper function, recursively searches in elements and their child nodes

 element    - HTML elements
 keyword    - string to search
 */

function uiWebview_HighlightAllOccurencesOfStringForElement(element,keyword) {
    if (element) {
        if (element.nodeType == 3) {        // Text node

            var count = 0;
            var elementTmp = element;
            while (true) {
                var value = elementTmp.nodeValue;  // Search for keyword in text node
                var idx = value.toLowerCase().indexOf(keyword);

                if (idx < 0) break;

                count++;
                elementTmp = document.createTextNode(value.substr(idx+keyword.length));
            }

            uiWebview_SearchResultCount += count;

            var index = uiWebview_SearchResultCount;
            while (true) {
                var value = element.nodeValue;  // Search for keyword in text node
                var idx = value.toLowerCase().indexOf(keyword);

                if (idx < 0) break;             // not found, abort

                //we create a SPAN element for every parts of matched keywords
                var span = document.createElement("span");
                var text = document.createTextNode(value.substr(idx,keyword.length));
                span.appendChild(text);

                span.setAttribute("class","uiWebviewHighlight");
                span.style.backgroundColor="yellow";
                span.style.color="black";

                index--;
                span.setAttribute("id", "SEARCH WORD"+(index));
                //span.setAttribute("id", "SEARCH WORD"+uiWebview_SearchResultCount);

                //element.parentNode.setAttribute("id", "SEARCH WORD"+uiWebview_SearchResultCount);

                //uiWebview_SearchResultCount++;    // update the counter

                text = document.createTextNode(value.substr(idx+keyword.length));
                element.deleteData(idx, value.length - idx);

                var next = element.nextSibling;
                //alert(element.parentNode);
                element.parentNode.insertBefore(span, next);
                element.parentNode.insertBefore(text, next);
                element = text;
            }


        } else if (element.nodeType == 1) { // Element node
            if (element.style.display != "none" && element.nodeName.toLowerCase() != 'select') {
                for (var i=element.childNodes.length-1; i>=0; i--) {
                    uiWebview_HighlightAllOccurencesOfStringForElement(element.childNodes[i],keyword);
                }
            }
        }
    }
}

// the main entry point to start the search
function uiWebview_HighlightAllOccurencesOfString(keyword) {
    uiWebview_RemoveAllHighlights();
    uiWebview_HighlightAllOccurencesOfStringForElement(document.body, keyword.toLowerCase());
}

// helper function, recursively removes the highlights in elements and their childs
function uiWebview_RemoveAllHighlightsForElement(element) {
    if (element) {
        if (element.nodeType == 1) {
            if (element.getAttribute("class") == "uiWebviewHighlight") {
                var text = element.removeChild(element.firstChild);
                element.parentNode.insertBefore(text,element);
                element.parentNode.removeChild(element);
                return true;
            } else {
                var normalize = false;
                for (var i=element.childNodes.length-1; i>=0; i--) {
                    if (uiWebview_RemoveAllHighlightsForElement(element.childNodes[i])) {
                        normalize = true;
                    }
                }
                if (normalize) {
                    element.normalize();
                }
            }
        }
    }
    return false;
}

// the main entry point to remove the highlights
function uiWebview_RemoveAllHighlights() {
    uiWebview_SearchResultCount = 0;
    uiWebview_RemoveAllHighlightsForElement(document.body);
}

function uiWebview_ScrollTo(idx) {
    var scrollTo = document.getElementById("SEARCH WORD" + idx);
    if (scrollTo) scrollTo.scrollIntoView();
}