一、創建網絡請求隊列
首先，創建網絡請求隊列，如下：
ASINetworkQueue *que = [[ASINetworkQueue alloc] init];
self.netWorkQueue = que;
[que release];
[self.netWorkQueue reset];
[self.netWorkQueue setShowAccurateProgress:YES];
[self.netWorkQueue go];
二、創建存放路徑
//初始化Documents路徑
NSString *path = [NSHomeDirectory() stringByAppendingPathComponent:@"Documents"];
//初始化臨時文件路徑
NSString *folderPath = [path stringByAppendingPathComponent:@"temp"];
//創建文件管理器
NSFileManager *fileManager = [NSFileManager defaultManager];
//判斷temp文件夾是否存在
BOOL fileExists = [fileManager fileExistsAtPath:folderPath];
if (!fileExists) {//如果不存在說創建,因爲下載時,不會自動創建文件夾
[fileManager createDirectoryAtPath:folderPath
withIntermediateDirectories:YES
attributes:nil
error:nil];
}
三、發送下載請求這裏對下面幾個對象說明一下：CustomCell是我自定義的cell，cell上面有下載和暫停兩個按鈕，其tag值爲cell所在的行，因此這裏的[sendertag]爲下載按鈕的tag值，self.downloadArray爲array數組對象，存放要下載的資源字典信息，在該字典中有一鍵爲URL，它對應的值就是我們下載鏈接。
這些東西，根據自己的實際需要改動一下即可使用
CustomCell *cell = (CustomCell *)[self.myTableView cellForRowAtIndexPath:[NSIndexPath indexPathForRow:[sender tag] inSection:0]];
NSString *filePath = [[self.downloadArray objectAtIndex:[sender tag]] objectForKey:@"URL"];
NSLog(@"filePath=%@",filePath);
//初始下載路徑
NSURL *url = [NSURL URLWithString:filePath];
//設置下載路徑
ASIHTTPRequest *request = [[ASIHTTPRequest alloc] initWithURL:url];
//設置ASIHTTPRequest代理
request.delegate = self;
//初始化保存ZIP文件路徑
NSString *savePath = [path stringByAppendingPathComponent:[NSString stringWithFormat:@"book_%d.zip",[sender tag]]];
//初始化臨時文件路徑
NSString *tempPath = [path stringByAppendingPathComponent:[NSString stringWithFormat:@"temp/book_%d.zip.temp",[sender tag]]];
//設置文件保存路徑
[request setDownloadDestinationPath:savePath];
//設置臨時文件路徑
[request setTemporaryFileDownloadPath:tempPath];
//設置進度條的代理,
[request setDownloadProgressDelegate:cell];
//設置是是否支持斷點下載
[request setAllowResumeForFileDownloads:YES];
//設置基本信息
[request setUserInfo:[NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithInt:[sender tag]],@"bookID",nil]];
NSLog(@"UserInfo=%@",request.userInfo);
//添加到ASINetworkQueue隊列去下載
[self.netWorkQueue addOperation:request];
//收回request
[request release];
三、暫停請求
這裏的cell下下載時的一樣，
CustomCell *cell = (CustomCell *)[self.myTableView cellForRowAtIndexPath:[NSIndexPath indexPathForRow:[sender tag] inSection:0]];
for (ASIHTTPRequest *request in [self.netWorkQueue operations]) {
NSInteger bookid = [[request.userInfo objectForKey:@"bookID"] intValue];//查看userinfo信息
if ([sender tag] == bookid) {//判斷ID是否匹配
//暫停匹配對象
[request clearDelegatesAndCancel];
}
}
四、ASIHTTPRequestDelegate回調方法
上面已經把下載請求與暫停請求實現，點擊下載時，開始下載資源；當點暫停時，下載中斷；當我們再點擊下載按鈕時，繼續下載，在第二步的[request setAllowResumeForFileDownloads:YES]設置是是否支持斷點下載。下面要實現ASIHTTPRequestDelegate代理方法如下：
#pragma mark -
#pragma mark ASIHTTPRequestDelegate method
//ASIHTTPRequestDelegate,下載之前獲取信息的方法,主要獲取下載內容的大小，可以顯示下載進度多少字節
- (void)request:(ASIHTTPRequest *)request didReceiveResponseHeaders:(NSDictionary *)responseHeaders {
NSLog(@"didReceiveResponseHeaders-%@",[responseHeaders valueForKey:@"Content-Length"]);
NSLog(@"contentlength=%f",request.contentLength/1024.0/1024.0);
int bookid = [[request.userInfo objectForKey:@"bookID"] intValue];
NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];
float tempConLen = [[userDefaults objectForKey:[NSString stringWithFormat:@"book_%d_contentLength",bookid]] floatValue];
NSLog(@"tempConLen=%f",tempConLen);
//如果沒有保存,則持久化他的內容大小
if (tempConLen == 0 ) {//如果沒有保存,則持久化他的內容大小
[userDefaults setObject:[NSNumber numberWithFloat:request.contentLength/1024.0/1024.0] forKey:[NSString stringWithFormat:@"book_%d_contentLength",bookid]];
}
}
//ASIHTTPRequestDelegate,下載完成時,執行的方法
- (void)requestFinished:(ASIHTTPRequest *)request {
int bookid = [[request.userInfo objectForKey:@"bookID"] intValue];
CustomCell *cell = (CustomCell *)[self.myTableView cellForRowAtIndexPath:[NSIndexPath indexPathForRow:bookid inSection:0]];
cell.downloadCompleteStatus = YES;
cell.progressView.progress = 0.0;
}
經過上述步驟，一個支持斷點續傳的功能程序實現了！
