一、建立WKWebView和進度條

@property (nonatomic, strong) WKWebView         *webView;
@property (nonatomic, strong) UIProgressView    *progressView;

二、初始化UI

- (void)setupUI
{
    self.webView = [[WKWebView alloc] initWithFrame:CGRectMake(0, 0, self.view.bounds.size.width, self.view.bounds.size.height - D_TabbarSafeBottomMargin)];
 

    [self.view addSubview:self.webView];

    self.progressView = [[UIProgressView alloc] initWithProgressViewStyle:(UIProgressViewStyleDefault)];
    self.progressView.frame = CGRectMake(0, 0, self.webView.frame.size.width, 2);
    self.progressView.trackTintColor = [UIColor clearColor];
    self.progressView
 
.progressTintColor = [UIColor colorWithRed:75/255.0 green:181/255.0 blue:247/255.0 alpha:1.0];
    [self.progressView setProgress:0.1 animated:YES];
    [self.webView addSubview:self.progressView];
}

三、註冊和移除觀察者

- (void)_registerObserver
{
    [self.webView addObserver:self forKeyPath:@"estimatedProgress"
 
 options:(NSKeyValueObservingOptionNew) context:nil];
    [self.webView addObserver:self forKeyPath:@"title" options:(NSKeyValueObservingOptionNew) context:nil];
}

- (void)_removeObserver
{
    [self.webView removeObserver:self forKeyPath:@"estimatedProgress"];
    [self.webView removeObserver:self forKeyPath:@"title"];
}

四、載入連結這裡我們以百度為例

- (void)loadRequest
{
    NSURL *url = [NSURL URLWithString:@"http:www.baidu.com"];
    NSURLRequest *request = [NSURLRequest requestWithURL:url];
    [self.webView loadRequest:request];
}

五、實現觀察方法

/**
 觀察屬性變化
 @param keyPath 被觀察的屬性
 @param object 被觀察屬性的物件
 @param change 被觀察屬性的值的包括舊值和新值
 @param context 上下文
 */
- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary<NSKeyValueChangeKey,id> *)change context:(void *)context
{
    if ([object isEqual:self.webView] && [keyPath isEqualToString:@"estimatedProgress"]) {
        CGFloat newprogress = [[change objectForKey:NSKeyValueChangeNewKey] floatValue];
        if (newprogress >= 0.999) {
            [self.progressView setProgress:1.0 animated:YES];
            __weak typeof(self) weakSelf = self;
            dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.5 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
            //防止weakSelf指標為nil造成閃退
                __strong typeof(weakSelf) strongSelf = weakSelf;
                strongSelf.progressView.hidden = YES;
                [strongSelf.progressView setProgress:0 animated:NO];
            });
        } else {
            self.progressView.hidden = NO;
            [self.progressView setProgress:newprogress animated:YES];
        }
    }else if ([object isEqual:self.webView] && [keyPath isEqualToString:@"title"]) {
         self.title = (NSString *)[change objectForKey:NSKeyValueChangeNewKey];
    }
}

六、載入viewDidLoad函式

- (void)viewDidLoad {
    self.isRefresh = NO;
    self.edgesForExtendedLayout = UIRectEdgeNone;
    [self setTitle:LocalizedBlueOfficeForKey(@"載入web")];
    [self setupUI];
    [self _registerObserver];
    [self loadRequest];
}

7、在dealloc中移除觀察者

- (void)dealloc
{
    [self _removeObserver];
    [self _removeNotifacation];
}

總結：通過上述可以實現微信一樣的載入web有進度條顯示的效果，如果有其他要求可以在WKWebView的代理中進行處理