功能創建一個test.plist文件，textInput作為輸入，displayLabel作為顯示，有一個按鈕來觸發保持程序triggerStorage；

-(void)triggerStorage
{
    displayLabel.text = textInput.text;
    
    NSArray *paths=NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask,YES);
    NSString *path=[paths    objectAtIndex:0];  
    NSString *filename=[path stringByAppendingPathComponent:@"test.plist"];   //獲取路徑
    
    NSDictionary* dic2 = [NSDictionary dictionaryWithContentsOfFile:filename];  //讀取數據
    NSLog(@"dic2 is:%@",dic2); 
    
    //創建一個dic，寫到plist文件里
    NSDictionary* dic = [NSDictionary dictionaryWithObjectsAndKeys:displayLabel.text,@"IP",nil]; //寫入數據
    [dic writeToFile:filename atomically:YES];   

}

// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad
{
    NSMutableArray *resultData; 
    NSArray *paths=NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask,YES);
    NSString *path=[paths objectAtIndex:0];
    NSLog(@"path = %@",path);   
    NSString *filename=[path stringByAppendingPathComponent:@"test.plist"]; 
  
    //讀文件
    NSDictionary* dic2 = [NSDictionary dictionaryWithContentsOfFile:filename];
    NSLog(@"dic is:%@",dic2);    
    if(dic2 == nil)
    {
        //1. 創建一個plist文件 
        NSFileManager* fm = [NSFileManager defaultManager];
        [fm createFileAtPath:filename contents:nil attributes:nil];        
    }
    else
    {
        resultData=[dic2 objectForKey:@"IP"]; 
        if([dic2 count] > 0)
        {
            displayLabel.text = resultData;
        }
        else
        {
            displayLabel.text = @" ";
        }
    }
    self.navigationItem.rightBarButtonItem = [[[UIBarButtonItem alloc]   //按鈕的初始化及觸發條件設置
                                               initWithTitle:@"保存" 
                                               style:UIBarButtonItemStylePlain 
                                               target:self 
                                               action:@selector(triggerStorage)] autorelease];    
    [super viewDidLoad];
}

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參考代碼：

    NSLog(@"dic is:%@",dic2);