iOS中 断点下载详解 韩俊强的博客

#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

- (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());

}

- (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];
}

} else {
[sender setTitle:@"开始下载" forState:UIControlStateNormal];
[self.operation cancel];
_operation = nil;
}

}

- (unsigned long long)fileSizeAtPath:(NSString *)path
{
unsigned long long fileSize = 0;
NSFileManager *fileManager = [NSFileManager defaultManager];
if ([fileManager fileExistsAtPath:path]) {
NSError *error = nil;
NSDictionary *dict = [fileManager attributesOfItemAtPath:path error:&error];
if (dict && !error) {
fileSize = [dict fileSize];
}
}
return fileSize;
}