iOS开发问题：如何在两个视图控制器间传URL至UIWebView

Hey there! Let's get this URL handoff sorted out for your app. I'll break down the solution step by step with code examples tailored to both Objective-C and Swift, since you didn't specify which language you're using.

Step 1: Prepare the Second View Controller to Receive the URL #

First, we need to add a property to your second view controller so it can hold the URL passed from the first VC.

Objective-C #

In your SecondViewController.h:

#import <UIKit/UIKit.h>

@interface SecondViewController : UIViewController
@property (nonatomic, strong) NSURL *targetURL;
@end

Swift #

In your SecondViewController.swift:

import UIKit
// Import WebKit if you're using WKWebView (recommended over UIWebView)
import WebKit

class SecondViewController: UIViewController {
    // Property to store the incoming URL
    var targetURL: URL?
    private var webView: UIWebView! // Replace with WKWebView for newer iOS versions
}

Step 2: Pass the URL from the First View Controller #

Next, in your first view controller's button tap action, we'll grab the URL from the text field, validate it, then pass it to the second VC before navigating.

Objective-C #

In your FirstViewController.m:

- (IBAction)loadWebViewButtonTapped:(id)sender {
    // Get the text from your URL text field
    NSString *inputURLString = self.urlTextField.text;
    
    // Validate the input and convert to NSURL
    NSURL *targetURL = [NSURL URLWithString:inputURLString];
    if (targetURL && [UIApplication sharedApplication].canOpenURL:targetURL) {
        // Instantiate the second VC (adjust based on Storyboard or code creation)
        // Storyboard approach:
        SecondViewController *secondVC = [self.storyboard instantiateViewControllerWithIdentifier:@"SecondViewController"];
        // Code-based instantiation:
        // SecondViewController *secondVC = [[SecondViewController alloc] init];
        
        // Pass the URL
        secondVC.targetURL = targetURL;
        
        // Navigate (use push if in a UINavigationController, present otherwise)
        [self.navigationController pushViewController:secondVC animated:YES];
        // [self presentViewController:secondVC animated:YES completion:nil];
    } else {
        // Show error alert for invalid URL
        UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"Invalid URL"
                                                                       message:@"Please enter a valid web address (e.g., https://example.com)"
                                                                preferredStyle:UIAlertControllerStyleAlert];
        [alert addAction:[UIAlertAction actionWithTitle:@"OK" style:UIAlertActionStyleDefault handler:nil]];
        [self presentViewController:alert animated:YES completion:nil];
    }
}

Swift #

In your FirstViewController.swift:

@IBOutlet weak var urlTextField: UITextField!

@IBAction func loadWebViewTapped(_ sender: UIButton) {
    guard let inputURLString = urlTextField.text, 
          !inputURLString.isEmpty, 
          let targetURL = URL(string: inputURLString) else {
        showInvalidURLAlert()
        return
    }
    
    // Check if the URL can be opened
    if UIApplication.shared.canOpenURL(targetURL) {
        // Instantiate second VC
        guard let secondVC = storyboard?.instantiateViewController(withIdentifier: "SecondViewController") as? SecondViewController else {
            showInvalidURLAlert()
            return
        }
        
        // Pass the URL
        secondVC.targetURL = targetURL
        
        // Navigate
        navigationController?.pushViewController(secondVC, animated: true)
        // present(secondVC, animated: true)
    } else {
        showInvalidURLAlert()
    }
}

private func showInvalidURLAlert() {
    let alert = UIAlertController(title: "Invalid URL",
                                  message: "Please enter a valid web address (e.g., https://example.com)",
                                  preferredStyle: .alert)
    alert.addAction(UIAlertAction(title: "OK", style: .default))
    present(alert, animated: true)
}

Step 3: Load the URL in the Second View Controller's Web View #

Finally, we'll use the passed URL to load the webpage in the second VC's web view.

Objective-C #

In your SecondViewController.m:

#import "SecondViewController.h"

@interface SecondViewController ()
@property (nonatomic, strong) UIWebView *webView;
@end

@implementation SecondViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    // Set up UIWebView
    self.webView = [[UIWebView alloc] initWithFrame:self.view.bounds];
    self.webView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
    [self.view addSubview:self.webView];
    
    // Load the URL if it exists
    if (self.targetURL) {
        NSURLRequest *request = [NSURLRequest requestWithURL:self.targetURL];
        [self.webView loadRequest:request];
    }
}

@end

Swift #

In your SecondViewController.swift:

override func viewDidLoad() {
    super.viewDidLoad()
    setupWebView()
    loadTargetURL()
}

private func setupWebView() {
    // Set up UIWebView (replace with WKWebView for better performance)
    webView = UIWebView(frame: view.bounds)
    webView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
    view.addSubview(webView)
    
    // WKWebView setup (recommended):
    // webView = WKWebView(frame: view.bounds)
    // view.addSubview(webView)
}

private func loadTargetURL() {
    guard let url = targetURL else { return }
    let request = URLRequest(url: url)
    webView.loadRequest(request)
    // For WKWebView: webView.load(request)
}

Key Notes to Remember #

• Storyboard Identifier: If you're using Storyboards, make sure your second view controller has the identifier SecondViewController set in the Identity Inspector.
• UIWebView Deprecation: Apple has deprecated UIWebView since iOS 12. For apps targeting iOS 11+, use WKWebView instead—it's faster, more secure, and receives ongoing updates.
• Navigation Context: If your first view controller isn't embedded in a UINavigationController, use presentViewController instead of pushViewController to show the second VC.

内容的提问来源于stack exchange，提问作者Teodoro Villanueva