UIWebView启动两次-IOS

我正在使用下面的添加一个

ProgressView

，而

UIWebView

正在加载和卸载它。 问题是UIWebView启动了两次，ProgressView也启动了两次，因此当页面加载完成时，只有一个ProgressView被取消，而另一个没有

ViewController.h

#import <UIKit/UIKit.h>

@interface DirectionViewController : UIViewController <UIWebViewDelegate>
   @property (weak, nonatomic) IBOutlet UIWebView *directionWebView;
@end

---

不知道为什么它会打两次电话，但你可以这样做

if(!self.progressView){
self.progressView = [MRProgressOverlayView new];
    self.progressView.mode = MRProgressOverlayViewModeIndeterminateSmall;
    [self.view.window addSubview:self.progressView];
    [self.progressView setTintColor:self.yellowColor];
    [self.progressView setTitleLabelText:@"Loading ..."];
    [self.progressView show:YES];
}

-(void)webViewDidFinishLoad:(UIWebView *)webView
{
     [self.progressView dismiss:YES];
self.progressView  = nil;
}

可以多次调用此委托方法（例如在重定向的情况下）。因此，我建议将进度视图初始化代码移动到viewDidLoad方法

- (void)viewDidLoad {
    [super viewDidLoad];
    //...
    self.progressView = [MRProgressOverlayView new];
    self.progressView.mode = MRProgressOverlayViewModeIndeterminateSmall;
    [self.view.window addSubview:self.progressView];
    [self.progressView setTintColor:self.yellowColor];
    [self.progressView setTitleLabelText:@"Loading ..."];
}

-(BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType {
    NSLog(@"WebView start loading...");
    [self.progressView show:YES];
    return YES;
}

-(void)webViewDidFinishLoad:(UIWebView *)webView {
    [self.progressView dismiss:YES];
}

它可能会被触发多次，例如重定向、

iframe

加载等。在这里初始化对象非常不方便

对其使用

惰性初始化

设计模式

- (MRProgressOverlayView *)progressView {
    if (_progressView) {
        _progressView = [... alloc] init];
        // ... setup your progressView
    }
    return _progressView;
}

顺便说一句，您忘记了错误处理：

- (void)webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error
{
    // You need to stop loading indicator here, right?!
}

第二件事是-（可能对您来说这不是什么大问题），但通常很难准确确定UIWebView何时停止加载（所有加载的资源、AJAX请求等等）

就我个人而言，我正在使用下面的代码来管理

UIWebView的活动指示器启动/停止行为

#pragma mark UIWebViewDelegate

- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request
 navigationType:(UIWebViewNavigationType)navigationType
{
    NSLog(@"Webview (%p) starting to load URL: %@", self, request.URL);
    self.URL = request.URL;
    return YES;
}

- (void)webViewDidStartLoad:(UIWebView *)webView
{
    [self.spinner startAnimating];
    self.webViewLoadingCount++;
}

- (void)webViewDidFinishLoad:(UIWebView *)webView
{
    self.webViewLoadingCount--;
    if (self.webViewLoadingCount > 0) return;
    [self.spinner stopAnimating];
}

- (void)webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error
{
    self.webViewLoadingCount--;

    [self.spinner stopAnimating];

    // Ignore NSURLErrorDomain error (-999).
    if (error.code == NSURLErrorCancelled) return;

    // Ignore "Frame Load Interrupted" errors 
    if (error.code == 102 && [error.domain isEqual:@"WebKitErrorDomain"]) return;

    NSLog(@"WebView (%p) experienced an error: %@.", self, [error localizedDescription]);
}

---

谢谢你的回答@KDeogharkar

- (MRProgressOverlayView *)progressView {
    if (_progressView) {
        _progressView = [... alloc] init];
        // ... setup your progressView
    }
    return _progressView;
}

- (void)webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error
{
    // You need to stop loading indicator here, right?!
}

#pragma mark UIWebViewDelegate

- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request
 navigationType:(UIWebViewNavigationType)navigationType
{
    NSLog(@"Webview (%p) starting to load URL: %@", self, request.URL);
    self.URL = request.URL;
    return YES;
}

- (void)webViewDidStartLoad:(UIWebView *)webView
{
    [self.spinner startAnimating];
    self.webViewLoadingCount++;
}

- (void)webViewDidFinishLoad:(UIWebView *)webView
{
    self.webViewLoadingCount--;
    if (self.webViewLoadingCount > 0) return;
    [self.spinner stopAnimating];
}

- (void)webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error
{
    self.webViewLoadingCount--;

    [self.spinner stopAnimating];

    // Ignore NSURLErrorDomain error (-999).
    if (error.code == NSURLErrorCancelled) return;

    // Ignore "Frame Load Interrupted" errors 
    if (error.code == 102 && [error.domain isEqual:@"WebKitErrorDomain"]) return;

    NSLog(@"WebView (%p) experienced an error: %@.", self, [error localizedDescription]);
}