iPhone讀/寫.plist文件

Question

我正在製作一個應用程序，我需要存儲用戶提供的一些信息。我嘗試使用的.plist文件來存儲信息，我發現這一點：

NSString *filePath = @"/Users/Denis/Documents/Xcode/iPhone/MLBB/data.plist"; 
NSMutableDictionary* plistDict = [[NSMutableDictionary alloc] initWithContentsOfFile:filePath]; 
[plistDict setValue:@"Man" forKey:@"Gender"]; 
[plistDict writeToFile:filePath atomically: YES]; 

的問題是，因爲我在iPhone模擬器測試它的應用程序將只只要工作。我試過這個Changing Data in a Plist，但沒有運氣。我也讀過一些關於我需要將它添加到我的包中的內容，但是如何？

新代碼：

- (IBAction)segmentControlChanged{ 
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); 
NSString *documentsDirectory = [paths objectAtIndex:0]; 
NSString *plistLocation = [documentsDirectory stringByAppendingPathComponent:@"data.plist"]; 
NSMutableDictionary* plistDict = [[NSMutableDictionary alloc] initWithContentsOfFile:plistLocation]; 

if (Gender.selectedSegmentIndex == 0) { 
    [plistDict setObject:@"Man" forKey:@"Gender"]; 
    [plistDict writeToFile:plistLocation atomically: YES]; 
} 
else 
{ 
    [plistDict setObject:@"Women" forKey:@"Gender"]; 
    [plistDict writeToFile:plistLocation atomically: YES]; 
} 
} 

Answer 1

你在設備上使用相同的路徑？設備上的應用程序是沙盒，只能讀/寫文檔目錄中的文件。抓住該文件路徑like this並追加你的plist名稱。這種方法也適用於模擬器。

試試這個：

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); 
NSString *documentsDirectory = [paths objectAtIndex:0]; 
NSString *plistLocation = [documentsDirectory stringByAppendingPathComponent:@"myplist.plist"]; 

Answer 2

我猜你已經在Xcode中添加您的plist文件到您的資源文件夾（在這裏我們把圖像，如果沒有的話，你需要的地方，首先）。資源數據默認爲[NSBundle mainBundle]，iOS不允許我們更改包內的數據。所以首先您需要將該文件複製到文檔目錄。

以下是將文件NSBundle複製到Documents目錄的代碼。現在

- (NSString *)copyFileToDocumentDirectory:(NSString *)fileName { 
    NSError *error; 
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, 
                 NSUserDomainMask, 
                 YES); 
    NSString *documentsDir = [paths objectAtIndex:0]; 
    NSString *documentDirPath = [documentsDir 
             stringByAppendingPathComponent:fileName]; 

    NSArray *file = [fileName componentsSeparatedByString:@"."]; 
    NSString *filePath = [[NSBundle mainBundle] 
             pathForResource:[file objectAtIndex:0] 
                ofType:[file lastObject]]; 

    NSFileManager *fileManager = [NSFileManager defaultManager]; 
    BOOL success = [fileManager fileExistsAtPath:documentDirPath]; 

    if (!success) { 
     success = [fileManager copyItemAtPath:filePath 
             toPath:documentDirPath 
             error:&error]; 
     if (!success) { 
     NSAssert1(0, @"Failed to create writable txt file file with message \ 
             '%@'.", [error localizedDescription]); 
     } 
    } 

    return documentDirPath; 
} 

您可以使用返回documentDirPath訪問文件和操作（讀/寫）過這一點。

plist中的結構是：

<array> 
    <dict>key-value data</dict> 
    <dict>key-value data</dict> 
</array> 

這裏是代碼寫入數據到plist文件：

/* Code to write into file */ 

- (void)addToMyPlist { 
    // set file manager object 
    NSFileManager *manager = [NSFileManager defaultManager]; 

    // check if file exists 
    NSString *plistPath = [self copyFileToDocumentDirectory: 
                 @"MyPlistFile.plist"]; 

    BOOL isExist = [manager fileExistsAtPath:plistPath];  
    // BOOL done = NO; 

    if (!isExist) { 
     // NSLog(@"MyPlistFile.plist does not exist"); 
     // done = [manager copyItemAtPath:file toPath:fileName error:&error]; 
    } 
    // NSLog(@"done: %d",done); 

    // get data from plist file 
    NSMutableArray * plistArray = [[NSMutableArray alloc] 
              initWithContentsOfFile:plistPath]; 

    // create dictionary using array data and bookmarkKeysArray keys 
    NSArray *keysArray = [[NSArray alloc] initWithObjects:@"StudentNo", nil]; 
    NSArray *valuesArray = [[NSArray alloc] initWithObjects: 
            [NSString stringWithFormat:@"1234"], nil]; 

    NSDictionary plistDict = [[NSDictionary alloc] 
                initWithObjects:valuesArray 
                  forKeys:keysArray]; 

    [plistArray insertObject:poDict atIndex:0]; 

    // write data to plist file 
    //BOOL isWritten = [plistArray writeToFile:plistPath atomically:YES]; 
    [plistArray writeToFile:plistPath atomically:YES]; 

    plistArray = nil; 

    // check for status 
    // NSLog(@" \n written == %d",isWritten); 
}