在iPhone中加载网页并检查历史记录 [英] Loading a web page in iphone and check history

问题描述

伪代码

pageUrl = "http://www.google.com"

if(pageUrl == never Downloaded)
  Download pageUrl
else
{
   Display Saved Version
   Mean while download pageUrl
   When done display new version

}

如何在目标C中为UIWebview做类似的事情?另外，在这种情况下保存网页的最佳方法是什么?PList，SQLite吗?

How can I do something like this in objective C for a UIWebview? Also what's the best way to save web pages for this scenario? PList, SQLite?

推荐答案

Plist是解决问题的最佳方法.与SQLite数据库相比，iPhone/Objective-c可以非常快速地访问plist文件.

Plist is the best way to solve your problem. iPhone/Objective-c can access very quickly to plist file as compare to SQLite Database.

让我给您一些示例代码.

Let me give you some sample code.

请参阅-一段时间后编辑.

See - edit After some time.

• 创建项目的步骤&连接网络视图
  • 创建新项目->基于视图的应用程序.
  • 给名字起"yourProjName"(由您决定)
  • 打开"yourProjNameViewController.xib"
  • 拖动&放下UIWebView
  • 打开"yourProjNameViewController.h"文件
  • 放置变量 IBOutlet UIWebView * wView;
  • 在界面构建器中连接

  将属性列表文件添加到项目中的步骤

  Steps for adding Property list file to your project

  • 在项目树下扩展资源组
  • 右键单击资源"->添加->新文件
  • 选择模板类别-osx->资源
  • 选择属性列表文件
  • 提供文件名"LoadedURL.plist"
  • 将根类型"更改为数组"
  • 保存"LoadedURL.plist"文件

  现在将以下代码放置到"yourProjNameViewController.m"文件中.

  Now place following code to "yourProjNameViewController.m" file.

  #import "yourProjNameViewController.h"
  #define documentsDirectory_Statement NSString *documentsDirectory; \
  NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); \
  documentsDirectory = [paths objectAtIndex:0];
  
  
  @implementation WebViewLoadViewController
  
  
  - (void)viewDidLoad {
      [super viewDidLoad];
      // your url to load
      NSString *strToLoad=@"http://www.mail.yahoo.com";
  
  
      // file management code
      // copy file to documents directory
      documentsDirectory_Statement;
      NSFileManager *fm=[NSFileManager defaultManager];
      if(![fm fileExistsAtPath:[documentsDirectory stringByAppendingPathComponent:@"LoadedURL.plist"]]){
          [fm copyItemAtPath:[[NSBundle mainBundle] pathForResource:@"LoadedURL" ofType:@"plist"] 
                      toPath:[documentsDirectory stringByAppendingPathComponent:@"LoadedURL.plist"]
                       error:nil];
      }
  
      // array from doc-dir file
      NSMutableArray *ar=[NSMutableArray arrayWithContentsOfFile:[documentsDirectory stringByAppendingPathComponent:@"LoadedURL.plist"]];
  
      // check weather file has url data or not.
      BOOL fileLocallyAvailable=NO;
      NSString *strLocalFileName=nil;
      NSUInteger indexOfObject=0;
      if([ar count]>0){
          for (NSDictionary *d in ar) {
              if([[d valueForKey:@"URL"] isEqualToString:strToLoad]){
                  fileLocallyAvailable=YES;
                  strLocalFileName=[d valueForKey:@"FileName"];
                  break;
              }
              indexOfObject++;
          }
      }
      if(fileLocallyAvailable){
          NSDictionary *d=[ar objectAtIndex:indexOfObject];
          strLocalFileName=[d valueForKey:@"FileName"];
      } else {
          NSMutableDictionary *d=[NSMutableDictionary dictionary];
          [d setValue:strToLoad forKey:@"URL"];
  
          NSString *str=[[NSString alloc] initWithContentsOfURL:[NSURL URLWithString:strToLoad]];
  
          [str writeToFile:[documentsDirectory stringByAppendingPathComponent:[NSString stringWithFormat:@"%02i.htm",[ar count]]] 
                atomically:YES
                  encoding:NSUTF8StringEncoding error:nil];
  
          strLocalFileName=[NSString stringWithFormat:@"%02i.htm",[ar count]];
          [d setValue:[NSString stringWithFormat:@"%02i.htm",[ar count]] forKey:@"FileName"];
          [ar addObject:d];
  
          [ar writeToFile:[documentsDirectory stringByAppendingPathComponent:@"LoadedURL.plist"]
               atomically:YES];
      }
      NSURL *u=[[NSURL alloc] initFileURLWithPath:[documentsDirectory stringByAppendingPathComponent:strLocalFileName]];
      NSURLRequest *re=[NSURLRequest requestWithURL:u];
      [wView loadRequest:re];
      [u release];
  }
  

  `

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