使用 UIWebView 搜索以突出显示 PDF 中的文本

我是 ios 开发的新手，我有 UIWebView 用于显示来自 URL 的 Pdf 页面文章。我需要搜索字符串或文本并突出显示。我无法使用 UIWebView 搜索并突出显示 PDF 中的文本。Pdf 加载正常，但搜索文本未突出显示。它仅适用于我在 PDF 中需要的 html

Mycode

视图控制器.h

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

视图控制器.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

搜索WebView.h

#import <Foundation/Foundation.h>

@interface SearchWebView : UIWebView

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

@end

搜索WebView.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

搜索WebView.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);
}

就我而言，我通过在搜索栏和我的搜索栏中输入的文本从网页视图中加载的页面中搜索文本搜索WebView.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);
}

在我的 .m 中，我搜索在搜索栏中输入的任何文本，例如：

- (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];
}

我的highlightAllOccurencesOfString 方法的工作原理如下：

- (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];
}

我的removeAllHighlights方法是：

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

现在将所有这些与您的情况进行比较。希望对您有帮助。如果有任何疑问，请随时问我。