JavaScript 未从 Objective C 执行

Question

所以我有一个 WebView，它可以捕获网站中 URL 的变化以打开相机。 图片完成后，我想将其发回：

[self.webView stringByEvaluatingJavaScriptFromString:[NSString stringWithFormat:@"addImageiOS(%@)", base64EncodedImage]];

它不起作用，我猜是因为 self.webView 不是 webview。 我对这些代表和事情一团糟，我已经习惯了 Android。 好吧，我的代码在这里。

WebViewController.h

#import <UIKit/UIKit.h>

@interface WebViewController : UIViewController <UIWebViewDelegate>
@property (weak, nonatomic) IBOutlet UIWebView *webView;
@property (strong, nonatomic) IBOutlet UIToolbar *ToolBar;
@property (strong, nonatomic) IBOutlet UIBarButtonItem *MenuButton;

@end

WebViewController.m

#import "WebViewController.h"
@interface WebViewController ()
@end
@implementation WebViewController
@synthesize webView = _webView;

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
    // Custom initialization
}
return self;
}

- (void)webViewDidFinishLoad:(UIWebView *)webView {
NSString *js_result = [webView stringByEvaluatingJavaScriptFromString:@"document.location.href"];
NSLog(@"%@", js_result);
}

- (void)viewDidLoad
{
[super viewDidLoad];

_webView.delegate = self;

NSURL *url = [NSURL URLWithString:@"http://some_url"];
NSURLRequest *requestURL = [NSURLRequest requestWithURL:url];
[_webView loadRequest:requestURL];


// Do any additional setup after loading the view.
NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];

NSString *URL= [prefs stringForKey:@"URL"];

}

- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}


- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType {
NSURL *url = request.URL;
NSString *filePath= [url path];
//NSString *myString = [url absoluteString];
if ([filePath rangeOfString:@"TAKEPICWITHCAMERA"].location != NSNotFound) {
    //TAKE PIC WITH CAMERA
    [self openCamera];
    return NO;


}

return YES;
}

- (void)openCamera {

UIImagePickerController *picker = [[UIImagePickerController alloc] init];
picker.delegate = self;
picker.allowsEditing = YES;
picker.sourceType = UIImagePickerControllerSourceTypeCamera;

[self presentViewController:picker animated:YES completion:NULL];

}

#pragma mark - Image Picker Controller delegate methods

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {

UIImage *chosenImage = info[UIImagePickerControllerEditedImage];
NSString *base64EncodedImage = [self encodeToBase64String:chosenImage];
[self.webView stringByEvaluatingJavaScriptFromString:[NSString stringWithFormat:@"addImageiOS(%@)", base64EncodedImage]];
[picker dismissViewControllerAnimated:YES completion:NULL];

}

- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker {

[picker dismissViewControllerAnimated:YES completion:NULL];

}
- (NSString *)encodeToBase64String:(UIImage *)image {
return [UIImagePNGRepresentation(image) base64EncodedStringWithOptions:NSDataBase64Encoding64CharacterLineLength];
}

@end

这一定是我错过了一些小事。

Answer 1

可能只是在您的 JavaScript 调用中缺少引号：

@"addImageiOS(\"%@\")"