1.直接用NSURLConnection下载
#import "ViewController.h"
#import "DACircularProgressView.h"
/**
* NSURLConnectionDataDelegate协议中的代理方法
开始接收到服务器的响应时调用
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response;
接收到服务器返回的数据时调用（服务器返回的数据比较大时会调用多次）
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data;
服务器返回的数据完全接收完毕后调用
- (void)connectionDidFinishLoading:(NSURLConnection *)connection;
请求出错时调用（比如请求超时）
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error;
*/
@interface ViewController () <NSURLConnectionDataDelegate>
/**
* 用来写数据的文件句柄对象
*/
@property (nonatomic,strong)NSFileHandle *writeHandle;
/**
* 文件的总大小
*/
@property (nonatomic,assign)longlong totalLength;
/**
* 当前已经写入的文件大小
*/
@property (nonatomic,assign)longlong currentLength;
@property (nonatomic,weak)DACircularProgressView *circleView;//用这个类来添加下载进度条
@end
@implementation HMViewController
- (void)viewDidLoad
{
[superviewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
/**
* 用DACircularProgress这个类添加下载进度条
*/
DACircularProgressView *circleView = [[DACircularProgressViewalloc]init];
circleView.frame = CGRectMake(100, 50, 100, 100);
circleView.progressTintColor = [UIColorredColor];
circleView.trackTintColor = [UIColorblueColor];
circleView.progress = 0.01;
[self.viewaddSubview:circleView];
self.circleView = circleView;
}
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
// 1.URL
NSURL *url = [NSURLURLWithString:@"http://hd.shijue.cvidea.cn/tf/140422/2330218/5355ca2
f3dfae93acb000001.JPEG"];
// 2.请求
NSURLRequest *request = [NSURLRequestrequestWithURL:url];
// 3.下载(创建完conn对象后，会自动发起一个异步请求)
[NSURLConnectionconnectionWithRequest:requestdelegate:self];
}
#pragma mark - NSURLConnectionDataDelegate代理方法
/**
* 请求失败时调用（请求超时、网络异常）
*
* @param error 错误原因
*/
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
NSLog(@"didFailWithError");
}
/**
* 1.接收到服务器的响应就会调用 （先搞一个0kb的文件，然后用writeHandle关联那个文件，最后写入数据
* @param response 响应
*/
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
// 文件路径 沙盒中的caches的路径
NSString *caches = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory,NSUserDomainMask,YES)lastObject];
NSLog(@"caches = %@",caches);
//用这个stringByAppendingPathComponent:方法会自动添加一个/表示这是个路径
NSString *filepath = [cachesstringByAppendingPathComponent:@"photodownload.JPEG"];//先搞一个0kb的文件
// 创建一个空的文件到沙盒中
NSFileManager *mgr = [NSFileManagerdefaultManager];
[mgr createFileAtPath:filepathcontents:nilattributes:nil];
// 创建一个用来写数据的文件句柄
self.writeHandle = [NSFileHandlefileHandleForWritingAtPath:filepath];//然后用writeHandle关联那个文件
// 获得文件的总大小
self.totalLength = response.expectedContentLength;
}
/**
* 2.当接收到服务器返回的实体数据时调用（具体内容，这个方法可能会被调用多次）
*
* @param data 这次返回的数据
*/
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
// 移动到文件的最后面
[self.writeHandleseekToEndOfFile];
// 将数据写入沙盒（先移动到最后面再拼接）
[self.writeHandlewriteData:data]; //最后写入数据
// 累计文件的长度
self.currentLength += data.length;
NSLog(@"下载进度：%f", (double)self.currentLength/self.totalLength);
self.circleView.progress = (double)self.currentLength/self.totalLength;
}
/**
* 3.加载完毕后调用（服务器的数据已经完全返回后）
*/
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
self.currentLength =0;
self.totalLength =0;
// 关闭文件
[self.writeHandlecloseFile];
self.writeHandle =nil;
}
command + shift + g 来到这个路径
/Users/admin/Library/Developer/CoreSimulator/Devices/250BF271-B5CD-45D2-B549-0EEB38E8AEA7/data/Containers/Data/Application/E51E876C-B8B3-4998-AD56-3239909F68A9/Library/Caches
就可以看到下载的文件了
2.用AFURLConnectionOperation下载
// 1.URL
NSURL *url = [NSURLURLWithString:@"http://hd.shijue.cvidea.cn/tf/140422/2330218/5355ca2
f3dfae93acb000001.JPEG"];
// 2.请求
NSURLRequest *request = [NSURLRequest requestWithURL:url];
//3. AFURLConnectionOperationAFURLConnectionOperation *operation = [[AFHTTPRequestOperationalloc]initWithRequest:request];
operation.outputStream = [NSOutputStreamoutputStreamToFileAtPath:filePathappend:NO];
self.hud.labelText =@"正在下载";
[self.hudshow:YES];
[self.hudhide:YESafterDelay:10];
[operation setDownloadProgressBlock:^(NSUInteger bytesRead,longlong totalBytesRead,longlong totalBytesExpectedToRead) {
//下载的进度，如 0.53，就是 53%
float progress = (float)totalBytesRead / totalBytesExpectedToRead;
//下载完成后立即执行
if (progress ==1.0) {
// [self.hud hide:YES];
_haveDowned =true;
self.hud.labelText =@"下载成功!";
[self.hudshow:YES];
[self.hudhide:YESafterDelay:1];
NSLog(@" 下载完成 progress = %f",progress);
}else{
// [self.hud hide:YES];
self.hud.labelText =@"下载失败!";
[self.hudshow:YES];
[self.hudhide:YESafterDelay:1];
}
}];
//下载完成的事件该方法会在下载完成后延迟 2秒左右执行 根据完成后需要处理的及时性不高，可以采用该方法
[operation setCompletionBlock:^{
// NSLog(@"自然人凭证下载接口下载完成 ");
}];
[operation start];