javascript-iPhone应用程序中未调用shouldStartLoadWithRequest

2019-10-24 12:34:14 阅读：293 来源： 互联网

标签：objective-c event-handling cocoa-touch javascript iphone

我有一个带有UIWebView控制器的视图控制器.我正在尝试获取Web视图的html内容内的javascript,以将一些信息传递给我的目标c代码.我在网上遇到了许多示例,这些示例在javascript函数中设置window.location,然后捕获通过将视图控制器设置为Web视图的委托并将其捕获在shouldStartLoadWithRequest函数中而生成的事件.不幸的是,我无法使它正常工作,因为即使我设置了Web视图的委托,也从不调用shouldStartLoadWithRequest.

我的代码如下：

界面：

@interface StoryTextViewController : UIViewController <UIWebViewDelegate>
{
    IBOutlet UIWebView *storyWebView;   
    NSString *information;
}

@property (nonatomic, retain) IBOutlet UIWebView *storyWebView;
@property (nonatomic, retain) NSString *information;

@end

在界面中,* information变量由调用StoryTextViewController的上一个视图设置.

实现：

#import "StoryTextViewController.h"

@implementation StoryTextViewController

@synthesize storyWebView;
@synthesize information;

- (NSString *) contructHTMLText
{
    NSString *HTMLText = @"";

    NSArray *words = [information componentsSeparatedByString:@" "];
    NSString *header =
    @"<html>\n"
    "<head>\n"
    "<script type=\"text/javascript\">\n"

    "function marktext(theSpanID)\n"
    "{\n"
    "   var theSpan=document.getElementById(theSpanID);\n"
    "   if (theSpan.className == \"noHilite\")\n"
    "   {\n"
    "       theSpan.className = \"hilite\";\n"
    "       window.location = \"true\";\n"
    "   }\n"
    "   else\n"
    "   {\n"
    "       theSpan.className = \"noHilite\";\n"
    "       window.location = \"false\";\n"
    "   }\n"
    "}\n"

    "</script>\n"

    "<style type=\"text/css\">\n"

    ".hilite\n"
    "{\n"
    "   background-color:red;\n"
    "   color:white;\n"
    "   font: bold 60px arial,sans-serif\n"
    "}\n"

    ".noHilite\n"
    "{\n"
    "   background-color:white;\n"
    "   color:black;\n"
    "   font: 60px arial,sans-serif\n"
    "}\n"

    "</style>\n"

    "</head>\n"
    "<body>\n"
    "<div class=\"storyText\">\n";

    NSString *tailer = 
    @"</div>\n"
    "</body>\n"
    "</html>\n";

    HTMLText = [HTMLText stringByAppendingString:header];
    for (NSInteger i = 0; i < [words count]; i ++)
    {
        NSString *tag = [NSString stringWithFormat:@"   <span id=\"mytext%d\" class=\"noHilite\" onclick=\"marktext(\'mytext%d\')\">%@</span>&nbsp;\n", i, i, (NSString *)[words objectAtIndex:i]];
        HTMLText = [HTMLText stringByAppendingString:tag];
    }
    HTMLText = [HTMLText stringByAppendingString:tailer];
    NSLog(HTMLText);
    return HTMLText;
}

// The designated initializer. Override to perform setup that is required before the view is loaded.
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
    if (self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]) {
        storyWebView.delegate = self;
    }
    return self;
}

// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad
{
    [super viewDidLoad];
    NSString *HTMLData = [self contructHTMLText];
    [storyWebView loadHTMLString:HTMLData baseURL:[NSURL URLWithString: @""]];  
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning]; // Releases the view if it doesn't have a superview
    // Release anything that's not essential, such as cached data
}

- (void)dealloc {
    [super dealloc];
}

- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType 
{   
    // handle event here    
    return true;
}

@end

发生的事情是,基本上,constructHTML函数将文本包含在* information变量中,并使用一些html和javascript将文本中的每个单词包装起来,这样,每当单击单词时,都将对其加上css高亮显示.我想要做的是计算突出显示的单词的数量.我通过尝试在单击单词时调用的函数中传递某些内容来做到这一点,但是就像我说的那样,永远不会执行应该触发的shouldStartLoadWithRequest方法.

我已经看到很多人都在做这种事情,但是我似乎无法弄清楚为什么它不适合我

解决方法:

您可以在设置委托时设置断点

if (self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]) {
    storyWebView.delegate = self;
}

我很确定storyWebView在那一刻是零.

您可以通过以下方式修复它：

- (void)viewDidLoad
{
    [super viewDidLoad];
    NSString *HTMLData = [self contructHTMLText];
    // empty statement
    // the trick is that if the view is not loaded from the .nib yet
    // it will be loaded and all connections established

    if (self.view);

    // here is setting delegate
    storyWebView.delegate = self;
    [storyWebView loadHTMLString:HTMLData baseURL:[NSURL URLWithString: @""]];  
}

标签：objective-c,event-handling,cocoa-touch,javascript,iphone
来源： https://codeday.me/bug/20191024/1920763.html

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javascript-iPhone应用程序中未调用shouldStartLoadWithRequest