ios實現斷點下載

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#import "ZYDownViewController.h"

 

@interface ZYDownViewController ()

 

@end

 

@implementation ZYDownViewController

{

 

   // NSMutableData * buffer;

    long long  _totalLength; //檔案總大小

    long long  _currentLength; //當前下載大小  預設為0

    NSFileHandle * fileHandle;

    NSURLConnection * conn;

}

 

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil

{

    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];

    if (self) {

        // Custom initialization

    }

    return self;

}

 

- (void)viewDidLoad

{

    [super viewDidLoad];

    // Do any additional setup after loading the view from its nib.

    NSString * pp=[self getPath];

    fileHandle =[NSFileHandle fileHandleForWritingAtPath:pp];

    

    _progress.progressViewStyle=1;

    

}

 

- (void)didReceiveMemoryWarning

{

    [super didReceiveMemoryWarning];

    // Dispose of any resources that can be recreated.

}

- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error{

   

}

- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response{

    

    //buffer=[[NSMutableData alloc] init];

    _totalLength=[response expectedContentLength] + _currentLength;

  

    

 

}

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data{

 

    //[buffer appendData:data];

    if (fileHandle) {

        //定位到要寫入檔案的地方

        [fileHandle seekToFileOffset:[fileHandle seekToEndOfFile]];

        [fileHandle writeData:data];

    }

    _currentLength+=data.length;

    float f=(float)_currentLength/(float)_totalLength;

    _progress.progress=f;

    

 

}

- (void)connectionDidFinishLoading:(NSURLConnection *)connection{

    

    UIAlertView * alert=[[UIAlertView alloc]  initWithTitle:@"溫馨提示" message:@"下載成功" delegate:self cancelButtonTitle:@"返回"  otherButtonTitles:nil, nil];

    [alert show];

 

   

}

- (IBAction)DownBtnClick:(id)sender {

    

    //斷點下載

    NSString * path=[self getPath];   //擷取路徑

    long long filesize=0;

    

    NSFileManager * fileMg=[NSFileManager defaultManager];

    //擷取檔案資訊字典

    NSDictionary  *dic=[fileMg  attributesOfItemAtPath:path error:nil];

    

    // 擷取檔案大小

    NSNumber * contentLength=[dic objectForKey:NSFileSize];

    

    //擷取已經下載多少

    filesize=[contentLength longLongValue];

    _currentLength=filesize;

    //擷取下載檔案的大小

    NSURL * url=[NSURL URLWithString:@"http://localhost:8080/Servelet/3333.dmg"]; //測試服務代碼

   

    NSMutableURLRequest * request=[NSMutableURLRequest requestWithURL:url];

    [request setHTTPMethod:@"POST"];

    //佈建要求過後的位元組  因為我們要求都是在建立在已經擷取檔案的大小的基礎上的進行的

    [request addValue:[NSString stringWithFormat:@"bytes=%qu-",_currentLength] forHTTPHeaderField:@"Range"];

    conn=[NSURLConnection connectionWithRequest:request delegate:self];

   

    

    

    

    

}

-(NSString *) getPath{

 

    NSString * filePath=[NSHomeDirectory() stringByAppendingPathComponent:@"Documents/test.dmg"];

    NSFileManager * fileMg=[NSFileManager defaultManager];

    if (![fileMg fileExistsAtPath:filePath]) {

        

        [fileMg createFileAtPath:filePath contents:nil attributes:nil];

    }

    

    return filePath;

 

}

- (IBAction)CancelBtnClick:(id)sender {

    [conn cancel];

}

@end

 

ios實現斷點下載