大文件下载+Progress+暂停
2016-06-28 本文已影响53人
952625a28d0d
#import "ViewController.h"
@interface ViewController ()<NSURLConnectionDataDelegate>
@property (weak, nonatomic) IBOutlet UIImageView *imagView;
@property (weak, nonatomic) IBOutlet UIProgressView *progress; // 进度条
- (IBAction)startBtnClick:(id)sender; // 开始下载
- (IBAction)suspendBtnClick:(id)sender; // 暂停下载
//当前已经下载文件的大小
@property (nonatomic, assign) NSInteger currentLength;
//下载文件的总大小
@property (nonatomic, assign) NSInteger totalLength;
@property (nonatomic, strong) NSString *fullPath;
//文件句柄
@property (nonatomic, strong) NSFileHandle *handle ;
@property (nonatomic, strong) NSURLConnection *connect;
@end
@implementation ViewController
//开始下载
- (IBAction)startBtnClick:(id)sender {
//1.确定请求路径
NSURL *url = [NSURL URLWithString:@"http://120.25.226.186:32812/resources/videos/minion_01.mp4"];
//2.创建请求对象
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
/*
表示头500个字节：Range: bytes=0-499
表示第二个500字节：Range: bytes=500-999
表示最后500个字节：Range: bytes=-500
表示500字节以后的范围：Range: bytes=500-
*/
NSString *range = [NSString stringWithFormat:@"bytes=%zd-",self.currentLength];
[request setValue:range forHTTPHeaderField:@"Range"];
NSLog(@"%@",range);
//3.设置代理,发送请求
NSURLConnection *connect = [NSURLConnection connectionWithRequest:request delegate:self];
self.connect = connect;
}
//暂停
- (IBAction)suspendBtnClick:(id)sender {
NSLog(@"暂停--------------------%zd-",self.currentLength);
[self.connect cancel];
}
#pragma mark NSURLConnectionDataDelegate start
/*
1.接收到服务器响应的适合调用
*/
-(void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
NSLog(@"+++++++++++");
// 说明是暂停下载
if (self.currentLength > 0) {
return;
}
// 初始化文件管理器
NSFileManager *manager = [NSFileManager defaultManager];
// 保存下载的文件到沙盒
NSString *caches = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject];
//拼接文件全路径（这里采用的是文件响应系统建议的文件名字）
NSString *fullPath = [caches stringByAppendingPathComponent:response.suggestedFilename];
// 赋值给全路径
self.fullPath = fullPath;
//创建文件
[manager createFileAtPath:fullPath contents:nil attributes:nil];
NSLog(@"%@",fullPath);
//拿到文件的总大小
self.totalLength = response.expectedContentLength + self.currentLength;
NSLog(@"%zd",self.totalLength);
//创建文件句柄,指向数据写入的文件
self.handle = [NSFileHandle fileHandleForWritingAtPath:self.fullPath];
//指向从文件的末尾
[self.handle seekToEndOfFile];
}
/*
2.接收到服务器返回的数据,会调用多次
*/
-(void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
// 保存当前下载文件的进度
self.currentLength +=data.length;
// 写数据
[self.handle writeData:data];
// 设置Progress进度条的长度
NSLog(@"%f",1.0 *self.currentLength / self.totalLength);
self.progress.progress = 1.0 *self.currentLength / self.totalLength;
}
/*
3.当请求完成之后调用该方法
*/
-(void)connectionDidFinishLoading:(NSURLConnection *)connection
{
NSLog(@"connectionDidFinishLoading");
// 结束 滞空文件句柄
[self.handle closeFile];
self.handle = nil;
}
/*
4.当请求失败的适合调用该方法,如果失败那么error有值
*/
-(void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
NSLog(@"didFailWithError");
}
@end```
