Search to highlight text in PDF using UIWebView

Question

I am new in ios developement I have UIWebView for displays Pdf page articles from URL. I need to search string or text and highlight.I am not able to search and highlight the text in PDF using UIWebView.Pdf is loading fine but search text is not highlighting.its working only for html I need in PDF

Mycode

ViewController.h

#import <UIKit/UIKit.h>
#import "SearchWebView.h"
@interface ViewController : UIViewController<UIWebViewDelegate>
{
IBOutlet SearchWebView *webView1;
}
@end

ViewController.m

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad
{
[super viewDidLoad];
NSURL *targetURL = [NSURL URLWithString:@"http://www.adobe.com/content/dam/Adobe/en/devnet/acrobat/pdfs/pdf_open_parameters.pdf"];
NSURLRequest *request = [NSURLRequest requestWithURL:targetURL];
webView1.delegate=self;
[webView1 loadRequest:request];
[webView1 highlightAllOccurencesOfString:@"guide"];
}

-(void)webViewDidFinishLoad:(UIWebView *)webView
{
 [webView1 highlightAllOccurencesOfString:@"guide"];
}

@end

SearchWebView.h

#import <Foundation/Foundation.h>

@interface SearchWebView : UIWebView

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

@end

SearchWebView.m

#import "SearchWebView.h"

@implementation SearchWebView

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

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

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

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

@end

SearchWebView.js

 // We're using a global variable to store the number of occurrences
  var MyApp_SearchResultCount = 0;

 // helper function, recursively searches in elements and their child nodes
function MyApp_HighlightAllOccurencesOfStringForElement(element,keyword) {
if (element) {
    if (element.nodeType == 3) {        // Text node
        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

            var span = document.createElement("span");
            var text = document.createTextNode(value.substr(idx,keyword.length));
            span.appendChild(text);
            span.setAttribute("class","MyAppHighlight");
            span.style.backgroundColor="yellow";
            span.style.color="black";
            text = document.createTextNode(value.substr(idx+keyword.length));
            element.deleteData(idx, value.length - idx);
            var next = element.nextSibling;
            element.parentNode.insertBefore(span, next);
            element.parentNode.insertBefore(text, next);
            element = text;
            MyApp_SearchResultCount++;  // update the counter
        }
    } 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--) {
                MyApp_HighlightAllOccurencesOfStringForElement(element.childNodes[i],keyword);
            }
        }
    }
}
}

// the main entry point to start the search
function MyApp_HighlightAllOccurencesOfString(keyword) {
MyApp_RemoveAllHighlights();
MyApp_HighlightAllOccurencesOfStringForElement(document.body, keyword.toLowerCase());
}

// helper function, recursively removes the highlights in elements and their childs
function MyApp_RemoveAllHighlightsForElement(element) {
if (element) {
    if (element.nodeType == 1) {
        if (element.getAttribute("class") == "MyAppHighlight") {
            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 (MyApp_RemoveAllHighlightsForElement(element.childNodes[i])) {
                    normalize = true;
                }
            }
            if (normalize) {
                element.normalize();
            }
        }
    }
}
return false;
}

 // the main entry point to remove the highlights
function MyApp_RemoveAllHighlights() {
MyApp_SearchResultCount = 0;
MyApp_RemoveAllHighlightsForElement(document.body);
}

not using search bar progromatically i am going to search text [webView1 highlightAllOccurencesOfString:@"guide"]; — Ravindhiran, Nov 08 '13 at 10:14
How to search for multiple words like below? "The Path" Thank you :) — Jaydip Finava, Jan 21 '21 at 09:25

score 2 · Answer 1 · answered Nov 08 '13 at 10:19

In my case, I have searched text from a page load in web view through text enter in Search bar & my SearchWebView.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
            while (true) {
                //if (counter < 1) {
                var value = element.nodeValue;  // Search for keyword in text node
                var idx = value.toLowerCase().indexOf(keyword);

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

                //(value.split);

                //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="purple";
                span.style.color="white";

                uiWebview_SearchResultCount++;    // update the counter

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

And in my .m I have search any text enter in search bar like:

- (void)searchBarSearchButtonClicked:(UISearchBar *)searchBar
{
    [self removeAllHighlights];
    int resultCount = [self highlightAllOccurencesOfString:searchBar.text];
    if (resultCount <= 0)
    {
       alert = [[UIAlertView alloc] initWithTitle:@"No Match Found!"
                                                        message:[NSString stringWithFormat:@"No results found for this: %@", searchBar.text]
                                                       delegate:nil
                                              cancelButtonTitle:@"OK"
                                              otherButtonTitles:nil];
        [alert show];

    }
    [searchBar resignFirstResponder];
}

And my highlightAllOccurencesOfString method is working like:

- (NSInteger)highlightAllOccurencesOfString:(NSString*)str
{

    NSString *filePath  = [[NSBundle mainBundle] pathForResource:@"UIWebViewSearch" ofType:@"js" inDirectory:@""];
    NSData *fileData    = [NSData dataWithContentsOfFile:filePath];
    NSString *jsString  = [[NSMutableString alloc] initWithData:fileData encoding:NSUTF8StringEncoding];
    [webView stringByEvaluatingJavaScriptFromString:jsString];
    NSString *startSearch   = [NSString stringWithFormat:@"uiWebview_HighlightAllOccurencesOfString('%@')",str];
    [webView stringByEvaluatingJavaScriptFromString:startSearch];
    NSString *result        = [webView stringByEvaluatingJavaScriptFromString:@"uiWebview_SearchResultCount"];
    return [result integerValue];
}

And my removeAllHighlights method is:

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

Now compare all this with your situation. Hope it helps you. If any doubts then free to ask me.

pdf is loading fine but search result count always return 0 i don`t know why i getting 0 — Ravindhiran, Nov 08 '13 at 10:41
-(void)webViewDidFinishLoad:(UIWebView *)webView { int resultCount = [webView1 highlightAllOccurencesOfString:@"guide"]; NSLog(@"%d",resultCount); } — Ravindhiran, Nov 08 '13 at 10:41
The text that you have searched in web view is really on it? — Vishal, Nov 08 '13 at 10:46
Use this int resultCount = [self highlightAllOccurencesOfString:@"guide"]; — Vishal, Nov 08 '13 at 10:49
Also above line in place of this line: [webView1 highlightAllOccurencesOfString:@"guide"]; — Vishal, Nov 08 '13 at 10:49
let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/40810/discussion-between-ravindhiran-and-vishal) — Ravindhiran, Nov 08 '13 at 11:14

Search to highlight text in PDF using UIWebView

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