iOS 如何向 UIWebView loadRequest :? 添加完成 block

Question

我正在使用 UIWebView，并且已经在使用 webViewDidFinishLoad: 方法和一个在加载完成后执行的可选 block :

    -(void)webViewDidFinishLoad:(UIWebView *)webView
    {
        [super webViewDidFinishLoad:webView];

//... bunch of other code        

        if(self.webViewFinishLoadBlock != nil)
        {
            self.webViewFinishLoadBlock();
        }
    }

现在我正在处理一个更加复杂的加载页面和重定向序列，这使得上面的逻辑不够充分。我不想将自己注册为 dummyWebView 的委托(delegate)，并且不得不处理存储在我的 View Controller 属性中的多个完成 block :

    dummyWebView = [[UIWebView alloc] initWithFrame:CGRectZero];
    [dummyWebView loadRequest:[NSURLRequest requestWithURL:logoutURL]];
//Ideally here I would know when dummyWebView finishes loading, because there's some code I want to execute once it is done

我的问题是:

是否有某种第三方框架允许我使用 loadRequest:withCompletion: 来简化回调代码的编写？

Answer 1

你可以:

• UIWebView 的子类，具有保存 webViewDidFinish 完成 block 的属性；

• 确保它指定了它的委托(delegate)；

• 像您编写的那样实现 webViewDidFinish(尽管我建议该 block 同时返回 Web View 和 NSError 对象，如果有的话) );和

• 也实现 webView:didFailLoadWithError:。

因此:

//  MyWebView.h

#import <UIKit/UIKit.h>

typedef void(^WebViewFinishLoadBlock)(UIWebView *, NSError *);

@interface MyWebView : UIWebView

@property(nonatomic, copy) WebViewFinishLoadBlock webViewFinishLoadBlock;

- (void)loadRequest:(NSURLRequest *)request withCompletionHandler:(WebViewFinishLoadBlock)completionHandler;

@end

和

//  MyWebView.m

#import "MyWebView.h"

@interface MyWebView () <UIWebViewDelegate>
@end

@implementation MyWebView

- (void)loadRequest:(NSURLRequest *)request withCompletionHandler:(WebViewFinishLoadBlock)completionHandler
{
    self.delegate = self;
    self.webViewFinishLoadBlock = completionHandler;

    [self loadRequest:request];
}

#pragma mark - UIWebViewDelegate

- (void)webViewDidFinishLoad:(UIWebView *)webView
{
    if (self.webViewFinishLoadBlock) {
        self.webViewFinishLoadBlock(webView, nil);
        self.webViewFinishLoadBlock = nil;
    }
}

- (void)webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error
{
    if (self.webViewFinishLoadBlock) {
        self.webViewFinishLoadBlock(webView, error);
        self.webViewFinishLoadBlock = nil;
    }
}

@end

然后:

MyWebView *webView = [[MyWebView alloc] init];
webView.frame = self.view.bounds;
[self.view addSubview:webView];

NSURLRequest *request = [NSURLRequest requestWithURL:url];
[webView loadRequest:request withCompletionHandler:^(UIWebView *webView, NSError *error) {
    if (error) {
        NSLog(@"failed: %@", error);
    } else {
        NSLog(@"succeeded");
    }
}];