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布局如下:
基本拖拉属性:
#import "viewcontroller.h"
#import "afnetworking.h"
@interface viewcontroller ()
@property (weak, nonatomic) iboutlet uilabel *progresslabel;
@property (weak, nonatomic) iboutlet uiprogressview *progressview;
@property (nonatomic, strong) afhttprequestoperation *operation;
@end
@implementation viewcontroller
调用:
- (void)viewdidload
{
[super viewdidload];
nsstring *cachepath = nssearchpathfordirectoriesindomains(nscachesdirectory, nsuserdomainmask, yes).lastobject;
nsstring *txtpath = [cachepath stringbyappendingpathcomponent:@"mvtemp/mv.txt"];
nsfilemanager *filemanager = [nsfilemanager defaultmanager];
if ([filemanager fileexistsatpath:txtpath]) {
self.progressview.progress = [[nsstring stringwithcontentsoffile:txtpath encoding:nsutf8stringencoding error:nil] floatvalue];
self.progresslabel.text = [nsstring stringwithformat:@"%.2f%%", _progressview.progress * 100];
} else {
self.progressview.progress = 0;
self.progresslabel.text = @"0%";
}
nslog(@"%@", nshomedirectory());
}
点击事件:
- (ibaction)startorcanceldownload:(uibutton *)sender
if ([sender.currenttitle isequaltostring:@"开始下载"]) {
[sender settitle:@"暂停下载" forstate:uicontrolstatenormal];
nsstring *cachepath = nssearchpathfordirectoriesindomains(nscachesdirectory, nsuserdomainmask, yes).lastobject;
nsstring *filepath = [cachepath stringbyappendingpathcomponent:@"mv"];
nsstring *temppath = [cachepath stringbyappendingpathcomponent:@"mvtemp"];
nsfilemanager *filemanager = [nsfilemanager defaultmanager];
if (![filemanager fileexistsatpath:filepath]) {
[filemanager createdirectoryatpath:filepath withintermediatedirectories:yes attributes:nil error:nil];
}
if (![filemanager fileexistsatpath:temppath]) {
[filemanager createdirectoryatpath:temppath withintermediatedirectories:yes attributes:nil error:nil];
nsstring *mp4temppath = [temppath stringbyappendingpathcomponent:@"mv.temp"];
nsstring *txttemppath = [temppath stringbyappendingpathcomponent:@"mv.txt"];
nsstring *mp4path = [filepath stringbyappendingpathcomponent:@"mv.mp4"];
nsurl *url = [nsurl urlwithstring:@"http://video.szzhangchu.com/1442395443772_5176326090.mp4"];
nsurlrequest *request = [nsurlrequest requestwithurl:url];
unsigned long long downloadbytes = 0;
if ([filemanager fileexistsatpath:mp4temppath]) {
downloadbytes = [self filesizeatpath:mp4temppath];
nsstring *range = [nsstring stringwithformat:@"bytes=%llu-", downloadbytes];
nsmutableurlrequest *mutablerequest = [request mutablecopy];
[mutablerequest setvalue:range forhttpheaderfield:@"range"];
request = mutablerequest;
if (![filemanager fileexistsatpath:mp4path]) {
self.operation = [[afhttprequestoperation alloc] initwithrequest:request];
[self.operation setoutputstream:[nsoutputstream outputstreamtofileatpath:mp4temppath append:yes]];
__weak typeof(self) weakself = self;
[_operation setdownloadprogressblock:^(nsuinteger bytesread, long long totalbytesread, long long totalbytesexpectedtoread) {
weakself.progressview.progress = (float)(totalbytesread + downloadbytes) / (float)(totalbytesexpectedtoread + downloadbytes);
weakself.progresslabel.text = [nsstring stringwithformat:@"%.2f%%", weakself.progressview.progress * 100];
nsstring *progress = [nsstring stringwithformat:@"%.3f", weakself.progressview.progress];
[progress writetofile:txttemppath atomically:yes encoding:nsutf8stringencoding error:nil];
}];
[_operation setcompletionblockwithsuccess:^(afhttprequestoperation *operation, id responseobject) {
[filemanager moveitematpath:mp4temppath topath:mp4path error:nil];
[filemanager removeitematpath:txttemppath error:nil];
} failure:^(afhttprequestoperation *operation, nserror *error) {
[_operation start];
[sender settitle:@"开始下载" forstate:uicontrolstatenormal];
[self.operation cancel];
_operation = nil;
- (unsigned long long)filesizeatpath:(nsstring *)path
unsigned long long filesize = 0;
if ([filemanager fileexistsatpath:path]) {
nserror *error = nil;
nsdictionary *dict = [filemanager attributesofitematpath:path error:&error];
if (dict && !error) {
filesize = [dict filesize];
return filesize;
最终效果如下:
用到的第三方数据请求:afnetworking,大家应该都有,这里不做介绍
原文地址：http://blog.csdn.net/qq_31810357/article/details/49882769