xcode iPhone 读/写 .plist 文件

iPhone read/write .plist file

提问by Deni

I'm making a application where I need to store some information the user have provided. I try to use a .plist file to store the information, I found this:

我正在制作一个应用程序，我需要在其中存储用户提供的一些信息。我尝试使用 .plist 文件来存储信息，我发现：

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];

The problem is that the application will only work as long as I'm testing it in the iPhone simulator. I've tried this Changing Data in a Plistbut without luck. I have also read something about that I need to add it to my bundle, but how?

问题是该应用程序只有在我在 iPhone 模拟器中测试时才能工作。我试过这个在 Plist 中更改数据但没有运气。我也读过一些关于我需要将它添加到我的包中的内容，但是如何呢？

New code:

新代码：

- (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];
}
}

回答by Mrunal

I guess you have added your plist file to your resources folder in Xcode (where we place image, if not then you need to place that first). Resources data goes to [NSBundle mainBundle]by default and iOS does not allow us to change data inside bundle. So first you need to copy that file to Documents Directory.

我猜您已经将 plist 文件添加到 Xcode 中的资源文件夹中（我们放置图像的位置，如果没有，则需要先放置它）。资源数据[NSBundle mainBundle]默认进入，iOS 不允许我们更改 bundle 中的数据。所以首先你需要将该文件复制到文档目录。

Here is the code for copying file from NSBundleto the Documents directory.

这是将文件复制NSBundle到 Documents 目录的代码。

- (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;
}

Now you can use the returned documentDirPathto access that file and manipulate (Read/Write) over that.

现在您可以使用返回的documentDirPath来访问该文件并对其进行操作（读/写）。

The plist structure is:

plist的结构是：

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

Here is code to write data into plist file:

这是将数据写入 plist 文件的代码：

/* 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);
}

回答by Nick

Are you using that same path on your device? Apps on a device are sandboxed and can only read/write files in their documents directory. Grab that file path like thisand append your plist name. This approach will also work on the simulator.

您是否在设备上使用相同的路径？设备上的应用程序被沙盒化，只能读取/写入其文档目录中的文件。像这样获取该文件路径并附加您的 plist 名称。这种方法也适用于模拟器。

Try this:

尝试这个：

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