iOS Development-File Download (3 progress bar)

First, to achieve the download file progress control

1. Code examples

  1 #import "YYViewController.h" 2 3 @interface Yyviewcontroller () 4 @property (Nonatomic,strong) Nsmutabledata *fileda  Ta  5 @property (Nonatomic,strong) Nsfilehandle *writehandle;  6 @property (nonatomic,assign) long long currentlength;  7 @property (nonatomic,assign) long long sumlength;  8 @property (weak, nonatomic) Iboutlet Uiprogressview *progress; 9-(ibaction) star; @end @implementation Yyviewcontroller-(void) viewdidload + [Super Viewdidload]; 19} 20 2 1-(Ibaction) star {22 23 24//Create download path Nsurl *url=[nsurl urlwithstring:@ "http://192.168.0.109 : 8080/mjserver/resources/video.zip "]; 27 28//Create a request nsurlrequest *request=[nsurlrequest Requestwithurl:url]; 30 31//Send request (using proxy method)//Nsurlconnection *connt= [nsurlconnection connectionwithrequest:request Dele Gate:self]; //[connt start]; #pragma mark-nsurlconnectiondatadelegate Agent Method 39/* 40 * When receiving a response from the server (connecting the server) will be called in connection * * (void): (nsurlconnection *) connection didreceiveresponse: (nsurlresponse *) Response 43 {44/ /1. Creating a file storage path NSString *caches=[nssearchpathfordirectoriesindomains (nscachesdirectory, Nsuserdomainmask, YES) Lastobject]; NSString *filepath=[caches stringbyappendingpathcomponent:@ "Video.zip"]; 47 48 49 50//2. Create an empty file into the sandbox nsfilemanager *mgr=[nsfilemanager Defaultmanager]; 52//Just created the size is O byte [Mgr Createfileatpath:filepath contents:nil Attributes:nil]; 54 55//3. Create a file handle to write Data self.writehandle=[nsfilehandle Filehandleforwritingatpath:filepath]; 57 58//4. Get the full file length of self.sumlength=response.expectedcontentlength; 60} 61 62/* 63 * Called when data is received from the server (may be called multiple times, only partial data is delivered at a time) */-(void) connection: (Nsurlconnection *) connection Didreceiv EData: (NSData *) data 66 {67//cumulative received information Self.currentlength+=data.length; 69 70//Calculate current progress (converted to double type) 7 1 double progress= (double) self.currentlEngth/self.sumlength; self.progress.progress=progress; 73 74//1.1 points receive data. NSLog (@ "received data from the server! ---%d ", data.length); 76 77//writes data to the created empty file, but cannot use WriteToFile (overwrite) 78//To move to the tail of the file [Self.writehandle Seektoendoffile]; 80//From the current moving position, write Data bayi [Self.writehandle Writedata:data];     82} 83 84/* 85 * When the server's data is loaded, I/connectiondidfinishloading-(void) is called: (nsurlconnection *) connection 88 {89 NSLog (@ "Download complete"); 90 91//close connection, no longer input data in file [Self.writehandle CloseFile]; 93//Destroy 94 Self.writehandle=nil; 95 96//After the download is complete, the progress is emptied by self.currentlength=0; 98 self.sumlength=0; 99 100 101}102/*103 * Request error (failed) call (Request timeout \ network \ No net \, general refer to client Error) 104 */105-(void) connection: (Nsurlconnection *) Connec tion Didfailwitherror: (nserror *) error106 {107}108 @end

2. Display

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Tags: iOS development, network chapter

iOS Development-File Download (3 progress bar)