Mac开发学习_2

URL文件下载

1 打开XCode 新建一个工程UrlDownloader

2 打开MainMenu.xib 在视图上添加一个NSTextField,用于输入url地址

  再创建一个NSButton下载按钮

3 创建一个DownloadController文件

编码如下:

//
//  DownloadController.h
//  UrlDownloader
//
//  Created by Rogo on 4/20/12.
//  Copyright (c) 2012 Rogo.com. All rights reserved.
//

#import <Foundation/Foundation.h>

@interface DownloadController : NSObject <NSURLDownloadDelegate>
{
    IBOutlet NSTextField *textField;
    IBOutlet NSButton *downloadButton;
}

- (IBAction)startDownloadingURL:(id)sender;

@end

 

//
//  DownloadController.m
//  UrlDownloader
//
//  Created by Rogo on 4/20/12.
//  Copyright (c) 2012 Rogo.com. All rights reserved.
//

#import "DownloadController.h"

@implementation DownloadController

- (void)startDownloadingURL:sender
{
    NSURL *url = [NSURL URLWithString:[textField stringValue]];
    NSLog(@"Start download URL: %@", [url absoluteString]);
    
    // Create a url request
    NSURLRequest *theRequest = [NSURLRequest requestWithURL:url cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:60.0];
    
    // The download starts immediately upon receiving the 
    // initWithRequest:delegate: message
    NSURLDownload *theDownload = [[NSURLDownload alloc] initWithRequest:theRequest 
                                                               delegate:self];
    if (theDownload)
    {
    }
}

- (void)downloadDidBegin:(NSURLDownload *)download
{
    NSLog(@"download begin");
}

- (void)download:(NSURLDownload *)download decideDestinationWithSuggestedFilename:(NSString *)filename
{
    NSString *destinationFilename;
    NSString *homeDirectory = NSHomeDirectory();
    
    destinationFilename = [[homeDirectory stringByAppendingPathComponent:@"Desktop"]
                           stringByAppendingPathComponent:filename];
    [download setDestination:destinationFilename allowOverwrite:NO];
    NSLog(@"Destination Filename: %@", destinationFilename);
}

- (void)downloadDidFinish:(NSURLDownload *)download
{
    NSLog(@"download finish");
}

- (void)download:(NSURLDownload *)download didFailWithError:(NSError *)error
{
    NSLog(@"downoad error");
}

@end

 4 打开MainMenu.xib，拖拽一个新的NSObject对象，选中该对象，打开indentity inspector面板，将Class 指向到刚刚创建的DownloadController类

5 将视图与代码关联

 

6 保存工程 编译运行,输入要下载文件的地址下载，文件就下载到桌面了