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活动指示器从加载结束时开始

xcode iphone

N Fard · 技术社区 · 15 年前

我的代码怎么了?

我希望当view1.nib开始加载时自旋体指示器开始。所以我把[spinner startanimating];放在-(void)viewdidload中。但它会得到那个URL,然后启动spinner指示器…

- (void)viewDidLoad {








[spinner startAnimating];

NSURL *originalUrl=[NSURL URLWithString:@"http://example.com/"];
NSData *data=nil;  
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:originalUrl cachePolicy:NSURLRequestReloadIgnoringCacheData timeoutInterval:10];
NSURLResponse *response;
NSError *error;
data = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&error];


NSURL *LastURL=[response URL];


NSLog(@"%@",LastURL);



[backr,backrm,downloadr  setEnabled:FALSE];

backr.hidden=YES;
backrm.hidden=YES;
downloadr.hidden=YES;
[self nextr:0];
[super viewDidLoad];

}

2 回复 | 直到 15 年前

Yannick Loriot 15 年前

您的问题是使用sendSynchronousRequest阻塞了主线程。当数据下载的时候,你的线程被阻塞了,你的动画也被阻塞了,当请求完成后,动画继续。

我应该使用connectionWithRequest:delegate:或initWithRequest:delegate:方法并将委托设置为self。您可以在此处找到更多信息: Using NSURLConnection

编辑:

例子:

在界面中定义它:

@interface YourInterface {
@private
   NSMutableData *receivedData;
}

然后在控制器中加载到视图中:

// your previous definition of your NSMutableRequest

NSURLConnection *theConnection = [[NSURLConnection alloc] initWithRequest:request delegate:self];

if (theConnection) {
    // Create the NSMutableData that will hold
    // the received data
    // receivedData is declared as a method instance elsewhere
    receivedData=[[NSMutableData data] retain];
} else {
    // inform the user that the download could not be made
}

要完成,再次在控制器中实现以下方法:

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data{
    // append the new data to the receivedData
    // receivedData is declared as a method instance elsewhere
    [receivedData appendData:data];
}

- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {
    // release the connection, and the data object
    [connection release];

    // receivedData is declared as a method instance elsewhere
    [receivedData release];

    // inform the user
    NSLog(@"Connection failed! Error - %@ %@",
          [error localizedDescription],
          [[error userInfo] objectForKey:NSErrorFailingURLStringKey]);
}

- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
    // do something with the data
    // receivedData is declared as a method instance elsewhere
    NSLog(@"Succeeded! Received %d bytes of data",[receivedData length]);

    // release the connection, and the data object
    [connection release];
    [receivedData release];
}

Tom Irving 15 年前

您正在主线程上同步下载数据,因此UI将挂起,直到操作完成。这就是为什么你的旋转只能在完成时显示。

要么在后台线程中运行下载,要么使用nsurlconnection的异步方法。