Question

如何在WKWebView中显示进度条及HTML的title

Answer 1

WKWebView 的estimatedProgress和title 都是KVO模式，所以可以添加监听：
[webView addObserver:self forKeyPath:@"estimatedProgress" options:NSKeyValueObservingOptionNew context:NULL];
[webView addObserver:self forKeyPath:@"title" options:NSKeyValueObservingOptionNew context:NULL];

监听的实现方法：
- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {

if ([keyPath isEqualToString:@"estimatedProgress"]) {

if (object == webView) {
[self.progressView setAlpha:1.0f];
[self.progressView setProgress:self.currentSubView.webView.estimatedProgress animated:YES];

if(self.currentSubView.webView.estimatedProgress >= 1.0f) {

[UIView animateWithDuration:0.3 delay:0.3 options:UIViewAnimationOptionCurveEaseOut animations:^{
[self.progressView setAlpha:0.0f];
} completion:^(BOOL finished) {
[self.progressView setProgress:0.0f animated:NO];
}];

}
}
else
{
[super observeValueForKeyPath:keyPath ofObject:object change:change context:context];
}

}
else if ([keyPath isEqualToString:@"title"])
{
if (object == self.webView) {
self.title = self.webView.title;

}
else
{
[super observeValueForKeyPath:keyPath ofObject:object change:change context:context];

}
}
else {

[super observeValueForKeyPath:keyPath ofObject:object change:change context:context];
}
}

进度条增加了动画，类似safari的进度效果
注意销毁时一定要移除监听
[webView removeObserver:self forKeyPath:@"estimatedProgress"];
[webView removeObserver:self forKeyPath:@"title"];