IOS download feature: Breakpoint Download (pause and start) (Nsurlconnectiondatadelegate method)

1,model File Code

File name: HMFileDownloader.h

#import <Foundation/Foundation.h>

@interface Hmfiledownloader:nsobject

/**

* The remote URL of the file you want to download (the path to the connection server)

*/

@property (nonatomic, copy) NSString *url;

/**

* File storage path (where files are downloaded)

*/

@property (nonatomic, copy) NSString *destpath;

/**

* is downloading (there is no download, only the inside of the downloader to know)

*/

@property (Nonatomic, readonly, getter = isdownloading) BOOL downloading;

/**

* To monitor the download progress

*/

@property (nonatomic, copy) void (^progresshandler) (double progress);

/**

* To listen to the download complete

*/

@property (nonatomic, copy) void (^completionhandler) ();

/**

* Used to listen for download failure

*/

@property (nonatomic, copy) void (^failurehandler) (Nserror *error);

/**

* Start (Resume) Download

*/

-(void) start;

/**

* Pause Download

*/

-(void) pause;

@end

File name: HMFILEDOWNLOADER.M

#import "HMFileDownloader.h"

@interface Hmfiledownloader () <NSURLConnectionDataDelegate>

/**

* Connection Object

*/

@property (nonatomic, strong) nsurlconnection *conn;

/**

* File handle for writing data

*/

@property (nonatomic, strong) Nsfilehandle *writehandle;

/**

* Length of the currently downloaded data

*/

@property (nonatomic, assign) long long currentlength;

/**

* Total length of the full file

*/

@property (nonatomic, assign) long long totallength;

@end

@implementation Hmfiledownloader

/**

* Start (Resume) Download

*/

-(void) Start

{

Nsurl *url = [Nsurl URLWithString:self.url];

The default is a GET request

Nsmutableurlrequest *request = [Nsmutableurlrequest Requestwithurl:url];

Set Request header information

NSString *value = [NSString stringwithformat:@ "bytes=%lld-", self.currentlength];

[Request Setvalue:value forhttpheaderfield:@ "Range"];

Self.conn = [nsurlconnection connectionwithrequest:request delegate:self];

_downloading = YES;

}

/**

* Pause Download

*/

-(void) Pause

{

[Self.conn Cancel];

Self.conn = nil;

_downloading = NO;

}

#pragma mark-nsurlconnectiondatadelegate Proxy method

/**

* 1. When the response to the server is accepted (the server is connected) it is called

*/

-(void) connection: (Nsurlconnection *) connection didreceiveresponse: (Nsurlresponse *) response

{

#warning must judge

if (self.totallength) return;

1. Create an empty file into the sandbox

Nsfilemanager *mgr = [Nsfilemanager Defaultmanager];

The size you just created is 0 bytes.

[Mgr CreateFileAtPath:self.destPath Contents:nil Attributes:nil];

2. Create a file handle to write data

Self.writehandle = [Nsfilehandle FileHandleForWritingAtPath:self.destPath];

3. Get the full file length

Self.totallength = Response.expectedcontentlength;

}

/**

* 2. When data received to the server is called (may be called multiple times, each call will only pass part of the data)

*/

-(void) connection: (Nsurlconnection *) connection didreceivedata: (NSData *) data

{

Cumulative length

Self.currentlength + = Data.length;

NSLog (@ "=%lld==", self.currentlength);

Show progress

Double progress = (double) self.currentlength/self.totallength;

if (Self.progresshandler) {//Pass progress value to block

Self.progresshandler (progress);

}

Move to the end of a file

[Self.writehandle Seektoendoffile];

Writes data starting at the current moving position (end of file)

[Self.writehandle Writedata:data];

}

/**

* 3. When the server's data is accepted, it is called

*/

-(void) connectiondidfinishloading: (nsurlconnection *) connection

{

Emptying attribute values

self.currentlength = 0;

self.totallength = 0;

if (self.currentlength = = self.totallength) {

Close the connection (no longer entering data into the file)

[Self.writehandle CloseFile];

Self.writehandle = nil;

}

if (Self.completionhandler) {

Self.completionhandler ();

}

}

/**

* Request error (failure) when the call (Request timeout \ Network \ No network, generally referred to as client error)

*/

-(void) connection: (Nsurlconnection *) connection didfailwitherror: (Nserror *) error

{

if (Self.failurehandler) {

Self.failurehandler (Error);

}

}

@end

2. Drag the above two files to the project

3. Import in Controller file

#import "HMFileDownloader.h"

Statement

@property (nonatomic, strong) NSString *url;

@property (Retain, nonatomic) Uiprogressview *progressview;

@property (nonatomic, strong) Hmfiledownloader *filedownloader;

-(void) viewdidload

{

_progressview=[[uiprogressview Alloc]init];

_progressview.frame=cgrectmake (10, 150, 170, 20);

[Self.view Addsubview:_progressview];

[Self filedownloader];

}

-(void) Filedownloader

{

if (!_viewcont.filedownloader) {

_filedownloader = [[Hmfiledownloader alloc] init];

The file remote URL that needs to be downloaded

_filedownloader.url = @ "Http://192.168.1.9:8080/wyhouAppServices/upload/app_user/iOS%207%20Cookbook.pdf";

Where to save the file 1

NSString *caches = [Nssearchpathfordirectoriesindomains (nscachesdirectory, Nsuserdomainmask, YES) lastObject];

NSString *filepath = [Caches stringbyappendingpathcomponent:@ "20cookbook.pdf"];

Where to save the file 2

Nsurl *targeturl = [Nsurl Urlwithstring:_viewcont.filedownloader.url];

NSString *docpath = [self documentsdirectorypath];

Combine the filename and the path to the documents dir into the full path

NSString *pathtodownloadto = [NSString stringwithformat:@ "%@/%@", DocPath, [TargetUrl Lastpathcomponent]];

_filedownloader.destpath = Pathtodownloadto;

typeof (Ten) A = 20; int a = 20;

__weak typeof (self) VC = self;

_filedownloader.progresshandler = ^ (double progress) {

vc.progressview.progress=progress;

_progressview.progress = progress;

};

_filedownloader.completionhandler = ^{

NSLog (@ "------Download complete");

};

_filedownloader.failurehandler = ^ (Nserror *error) {

};

}else{

_progressview.progress= _viewcont.progressview.progress;

__weak typeof (self) VC = self;

_filedownloader.progresshandler = ^ (double progress) {

vc.progressview.progress=progress;

//

};

NSLog (@ "------");

}

return _filedownloader;

}

-(void) dealloc{

_progressview.progress=_progressview.progress;

}

Button text: "Start", "Pause"

-(void) Start {//Self.currentlength = = 200

if (_filedownloader.isdownloading) {//Pause download

[_filedownloader pause];

[_testbtn settitle:@ "Recovery" forstate:uicontrolstatenormal];

} else {//start download

[_filedownloader start];

[_testbtn settitle:@ "pause" forstate:uicontrolstatenormal];

}

}

IOS download feature: Breakpoint Download (pause and start) (Nsurlconnectiondatadelegate method)