將活動指示符添加到Web視圖

Question

我想在Web視圖中添加活動指示器。 但我不知道web視圖何時完成加載。 我開始在viewdidload動畫..

Answer 1

您不應該在viewDidLoad中開始制作動畫。 符合

UIWebViewDelegate

協議並使您的Web視圖委托您的視圖控制器，然后使用委托方法：

@interface MyVC: UIViewController <UIWebViewDelegate> {
    UIWebView *webView;
    UIActivityIndicatorView *activityIndicator;
}

@end

@implementation MyVC

- (id)init
{
    self = [super init];
    // ...

    activityIndicator = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhite];
    activityIndicator.frame = CGRectMake(x, y, w, h);
    [self.view addSubview:activityIndicator];

    webView = [[UIWebView alloc] initWithFrame:CGRectMake(x, y, w, h)];
    webView.delegate = self;
    // ...
    return self;
}

- (BOOL)webView:(UIWebView *)wv shouldStartLoadWithRequest:(NSURLRequest *)rq
{
    [activityIndicator startAnimating];
    return YES;
}

- (void)webViewDidFinishLoading:(UIWebView *)wv
{
    [activityIndicator stopAnimating];
}

- (void)webView:(UIWebView *)wv didFailLoadWithError:(NSError *)error
{
    [activityIndicator stopAnimating];
}

@end

Answer 2

實現UIWebViewDelegate協議這些是您需要在代碼中實現的委托：

- (void)webViewDidStartLoad:(UIWebView *)webView; //a web view starts loading
- (void)webViewDidFinishLoad:(UIWebView *)webView;//web view finishes loading
- (void)webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error; //web view failed to load

Answer 3

您將需要偵聽Web視圖委托回調以正確顯示您的活動指示器。

具體來說，你會想聽：

webViewDidStartLoad :(開始你的活動指標動畫）

webViewDidFinishLoad :(結束它）

webView：didFailLoadWithError :(結束它）

http://developer.apple.com/library/ios/#documentation/uikit/reference/UIWebViewDelegate_Protocol/Reference/Reference.html

Answer 4

- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view.

self.webViewRef.delegate = self;
NSURL *websiteUrl = [NSURL URLWithString:Constants.API_TERMS_AND_CONDITIONS_URL];
NSURLRequest *urlRequest = [NSURLRequest requestWithURL:websiteUrl];
[self.webViewRef loadRequest:urlRequest];
}

#pragma mark
#pragma  mark -- UIWebViewDelegate
- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType{
[self.activityIndicator startAnimating];
return YES;
}
 - (void)webViewDidStartLoad:(UIWebView *)webView{
[self.activityIndicator startAnimating];
 }
  - (void)webViewDidFinishLoad:(UIWebView *)webView{
[self.activityIndicator stopAnimating];
self.activityIndicator.hidden = YES;
 }
- (void)webView:(UIWebView *)webView didFailLoadWithError:(nullable NSError *)error{
[self.activityIndicator stopAnimating];
self.activityIndicator.hidden = YES;
 }