写一个iOS端离线下载的demo
时间: 2024-06-09 13:05:19 浏览: 15
好的,下面是一个简单的iOS端离线下载的demo:
1. 创建一个新的工程,导入AFNetworking库,用于网络请求和下载。
2. 创建一个下载管理类,例如:
```
@interface DownloadManager : NSObject
+ (instancetype)sharedManager;
- (void)startDownloadWithURL:(NSString *)urlString progress:(void (^)(CGFloat progress))progressBlock completion:(void (^)(BOOL success, NSString *filePath))completionBlock;
@end
```
3. 在下载管理类中实现 startDownloadWithURL:progress:completion: 方法,代码如下:
```
#import "DownloadManager.h"
#import <AFNetworking/AFNetworking.h>
@interface DownloadManager()
@property (nonatomic, strong) AFURLSessionManager *sessionManager;
@property (nonatomic, strong) NSURLSessionDownloadTask *downloadTask;
@property (nonatomic, copy) NSString *downloadFilePath;
@end
@implementation DownloadManager
+ (instancetype)sharedManager {
static DownloadManager *manager = nil;
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
manager = [[DownloadManager alloc] init];
manager.sessionManager = [[AFURLSessionManager alloc] initWithSessionConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration]];
});
return manager;
}
- (void)startDownloadWithURL:(NSString *)urlString progress:(void (^)(CGFloat progress))progressBlock completion:(void (^)(BOOL success, NSString *filePath))completionBlock {
NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:urlString]];
NSString *fileName = [urlString lastPathComponent];
NSString *downloadedFilePath = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) objectAtIndex:0];
self.downloadFilePath = [downloadedFilePath stringByAppendingPathComponent:fileName];
NSURLSessionDownloadTask *downloadTask = [self.sessionManager downloadTaskWithRequest:request progress:^(NSProgress * _Nonnull downloadProgress) {
CGFloat progress = 1.0 * downloadProgress.completedUnitCount / downloadProgress.totalUnitCount;
if (progressBlock) {
progressBlock(progress);
}
} destination:^NSURL * _Nonnull(NSURL * _Nonnull targetPath, NSURLResponse * _Nonnull response) {
return [NSURL fileURLWithPath:self.downloadFilePath];
} completionHandler:^(NSURLResponse * _Nonnull response, NSURL * _Nullable filePath, NSError * _Nullable error) {
BOOL success = NO;
if (!error) {
success = YES;
}
if (completionBlock) {
completionBlock(success, self.downloadFilePath);
}
}];
[downloadTask resume];
}
@end
```
4. 在需要进行离线下载的地方,调用下载管理类的 startDownloadWithURL:progress:completion: 方法即可:
```
[[DownloadManager sharedManager] startDownloadWithURL:@"http://example.com/example.pdf" progress:^(CGFloat progress) {
// 显示下载进度
} completion:^(BOOL success, NSString *filePath) {
if (success) {
// 下载成功,使用 filePath 进行处理
} else {
// 下载失败
}
}];
```
注意:这个demo只是一个简单的示例,实际使用时需要考虑更多的情况,例如下载进度的显示、下载的断点续传、下载文件的管理等。