本文为记录学习轨迹，内容抄袭自行走少年郎
这位大神
- 因为是抄袭，所以直接上代码了，想要看细节的，可点上方链接，去查看官方的详细文档
#import "DownLoadFileController.h"
@interface DownLoadFileController ()
@property (nonatomic, strong) UIProgressView *proView;
@property (nonatomic, strong) UILabel *lProText;
@property (nonatomic, strong) UIButton *bDonwload;
/** AFNetworking断点下载（支持离线）需用到的属性 **********/
/** 文件的总长度 */
@property (nonatomic, assign) NSInteger fileLength;
/** 当前下载长度 */
@property (nonatomic, assign) NSInteger currentLength;
/** 文件句柄对象 */
@property (nonatomic, strong) NSFileHandle *fileHandle;
/** 下载任务 */
@property (nonatomic, strong) NSURLSessionDataTask *downloadTask;
/* AFURLSessionManager */
@property (nonatomic, strong) AFURLSessionManager *manager;
@end
@implementation DownLoadFileController
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view.
self.view.backgroundColor = [UIColor whiteColor];
[self createUI];//创建UI
}
/**
* manager的懒加载
*/
- (AFURLSessionManager *)manager {
if (!_manager) {
NSURLSessionConfiguration *configuration = [NSURLSessionConfiguration defaultSessionConfiguration];
// 1. 创建会话管理者
_manager = [[AFURLSessionManager alloc] initWithSessionConfiguration:configuration];
}
return _manager;
}
/**
* downloadTask的懒加载
*/
- (NSURLSessionDataTask *)downloadTask {
if (!_downloadTask) {
// 创建下载URL
NSURL *url = [NSURL URLWithString:@"http://dldir1.qq.com/qqfile/QQforMac/QQ_V5.4.0.dmg"];
// 2.创建request请求
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
// 设置HTTP请求头中的Range
NSString *range = [NSString stringWithFormat:@"bytes=%zd-", self.currentLength];
[request setValue:range forHTTPHeaderField:@"Range"];
__weak typeof(self) weakSelf = self;
//下载完成
_downloadTask = [self.manager dataTaskWithRequest:request completionHandler:^(NSURLResponse * _Nonnull response, id _Nullable responseObject, NSError * _Nullable error) {
NSLog(@"dataTaskWithRequest");
// 清空长度
weakSelf.currentLength = 0;
weakSelf.fileLength = 0;
// 关闭fileHandle
[weakSelf.fileHandle closeFile];
weakSelf.fileHandle = nil;
}];
//创建文件路径
[self.manager setDataTaskDidReceiveResponseBlock:^NSURLSessionResponseDisposition(NSURLSession * _Nonnull session, NSURLSessionDataTask * _Nonnull dataTask, NSURLResponse * _Nonnull response) {
NSLog(@"NSURLSessionResponseDisposition");
// 获得下载文件的总长度：请求下载的文件长度 + 当前已经下载的文件长度
weakSelf.fileLength = response.expectedContentLength + self.currentLength;
// 沙盒文件路径
NSString *path = [[NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:@"QQ_V5.4.0.dmg"];
NSLog(@"File downloaded to: %@",path);
// 创建一个空的文件到沙盒中
NSFileManager *manager = [NSFileManager defaultManager];
if (![manager fileExistsAtPath:path]) {
// 如果没有下载文件的话，就创建一个文件。如果有下载文件的话，则不用重新创建(不然会覆盖掉之前的文件)
[manager createFileAtPath:path contents:nil attributes:nil];
}
// 创建文件句柄
weakSelf.fileHandle = [NSFileHandle fileHandleForWritingAtPath:path];
// 允许处理服务器的响应，才会继续接收服务器返回的数据
return NSURLSessionResponseAllow;
}];
//下载中。。。
[self.manager setDataTaskDidReceiveDataBlock:^(NSURLSession * _Nonnull session, NSURLSessionDataTask * _Nonnull dataTask, NSData * _Nonnull data) {
NSLog(@"setDataTaskDidReceiveDataBlock");
// 指定数据的写入位置 -- 文件内容的最后面
[weakSelf.fileHandle seekToEndOfFile];
// 向沙盒写入数据
[weakSelf.fileHandle writeData:data];
// 拼接文件总长度
weakSelf.currentLength += data.length;
// 获取主线程，不然无法正确显示进度。
NSOperationQueue* mainQueue = [NSOperationQueue mainQueue];
[mainQueue addOperationWithBlock:^{
// 下载进度
if (weakSelf.fileLength == 0) {
weakSelf.proView.progress = 0.0;
weakSelf.lProText.text = [NSString stringWithFormat:@"当前下载进度:00.00%%"];
} else {
weakSelf.proView.progress = 1.0 * weakSelf.currentLength / weakSelf.fileLength;
weakSelf.lProText.text = [NSString stringWithFormat:@"当前下载进度:%.2f%%",100.0 * weakSelf.currentLength / weakSelf.fileLength];
}
}];
}];
}
return _downloadTask;
}
/**
* 获取已下载的文件大小
*/
- (NSInteger)fileLengthForPath:(NSString *)path{
NSInteger fileLength = 0;
NSFileManager *fileManager = [[NSFileManager alloc] init]; // default is not thread safe
if ([fileManager fileExistsAtPath:path]) {
NSError *error = nil;
NSDictionary *fileDict = [fileManager attributesOfItemAtPath:path error:&error];
if (!error && fileDict) {
fileLength = [fileDict fileSize];
}
}
return fileLength;
}
#pragma mark - 创建UI
-(void)createUI{
//进度条
[self.view addSubview:self.progressView];
[self.proView mas_makeConstraints:^(MASConstraintMaker *make) {
make.width.top.mas_equalTo(200);
make.centerX.mas_equalTo(self.view.mas_centerX);
}];
//显示进度
[self.view addSubview:self.labelText];
[self.lProText mas_makeConstraints:^(MASConstraintMaker *make) {
make.left.right.mas_equalTo(0);
make.top.mas_equalTo(self.proView.mas_bottom).offset(10);
}];
//下载按钮
[self.view addSubview:self.button];
[self.bDonwload mas_makeConstraints:^(MASConstraintMaker *make) {
make.width.mas_equalTo(90);
make.top.mas_equalTo(self.lProText.mas_bottom).offset(20);
make.centerX.mas_equalTo(self.view.mas_centerX);
}];
}
#pragma mark - 进度条
-(UIProgressView *)progressView{
if (!_proView) {
_proView = [UIProgressView new];
}
return _proView;
}
#pragma mark - 显示进度
-(UILabel *)labelText{
if (!_lProText) {
_lProText = [UILabel new];
_lProText.textColor = [UIColor blueColor];
_lProText.textAlignment = NSTextAlignmentCenter;
_lProText.font = [UIFont systemFontOfSize:14];
}
return _lProText;
}
#pragma mark - 下载按钮
-(UIButton *)button{
if (!_bDonwload) {
_bDonwload = [UIButton new];
[_bDonwload setTitle:@"开始下载" forState:0];
[_bDonwload setTitleColor:[UIColor whiteColor] forState:0];
_bDonwload.titleLabel.font = [UIFont systemFontOfSize:14];
_bDonwload.backgroundColor = [UIColor redColor];
[_bDonwload addTarget:self action:@selector(bDLAction:) forControlEvents:UIControlEventTouchUpInside];
}
return _bDonwload;
}
-(void)bDLAction:(UIButton *)sender{
sender.selected = !sender.isSelected;
NSLog(@"sender = %@",sender.selected ? @"YES" : @"NO");
if (sender.selected) { // [开始下载/继续下载]
[sender setTitle:@"暂停下载" forState:0];
// 沙盒文件路径
NSString *path = [[NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:@"QQ_V5.4.0.dmg"];
NSInteger currentLength = [self fileLengthForPath:path];
if (currentLength > 0) { // [继续下载]
self.currentLength = currentLength;
}
[self.downloadTask resume];
} else {
[sender setTitle:@"开始下载" forState:0];
[self.downloadTask suspend];
self.downloadTask = nil;
}
}
@end
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