ios - 使用 UIWebView 搜索以突出显示 PDF 中的文本

Question

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 搜索和突出显示 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 PDF 中我需要的 html

我的代码

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);
}

Answer 1

在我的例子中，我通过在搜索栏和我的 SearchWebView.js

中输入的文本从 Web View 中的页面加载中搜索文本

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，我搜索了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 方法的工作方式如下:

- (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。希望对你有帮助。如果有任何疑问，请随时问我。