Question

我们需要能够读入现有plist文件的内容，然后添加到数组/字典中，然后将此新数据写入plist文件。狭窄很简单。我们想要多个根密钥作为数组，每个根密钥都有几个值。结构看起来像这样，

124818240124810284.JPG          Array
                item 0          String     Some Attribute 1
                item 1          String     Some Attribute 2

到目前为止，我们可以创建上述内容而没有任何问题。但是，只要我们将另一个数组写入plist，文件就会被覆盖，所有当前内容都会丢失。我们需要做的是阅读上面的内容并添加它，以便我们得到类似的东西，

124818240124810284.JPG          Array
                item 0          String     Some Attribute 1
                item 1          String     Some Attribute 2
354273577823597297.JPG          Array
                item 0          String     Some Attribute 1
                item 1          String     Some Attribute 2

等等。我们现在感到茫然，并且一直在努力解决这个问题。请尽可能帮助你！在此先感谢!!

我们目前正在编写此文件如下

NSString *plistPath = [documentsDirectory stringByAppendingPathComponent:@"Gallery.plist"];

// set the variables to the values in the text fields
NSMutableArray *myPhotos = [[NSMutableArray alloc] initWithCapacity:2];
[myPhotos addObject:@"NO"];
[myPhotos addObject:@"NO"];


// create dictionary with values in UITextFields
NSDictionary *plistDict = [NSDictionary dictionaryWithObjects: [NSArray  arrayWithObjects: myPhotos, nil] forKeys:[NSArray arrayWithObjects: self.photoName, nil]];

NSString *error = nil;

// create NSData from dictionary
NSData *plistData = [NSPropertyListSerialization dataFromPropertyList:plistDict format:NSPropertyListXMLFormat_v1_0 errorDescription:&error];

// check is plistData exists
if(plistData) {
    // write plistData to our Data.plist file
        [plistData writeToFile:plistPath atomically:YES];
}else{
        NSLog(@"Error in saveData: %@", error);
        [error release];
}

以下是我们最终的结果

NSString *plistPath = [documentsDirectory stringByAppendingPathComponent:@"Gallery.plist"];

// Get current content.
NSDictionary *oldContent = [NSDictionary dictionaryWithContentsOfFile:plistPath];
// Make a mutable copy.
NSMutableDictionary *newContent = [[oldContent mutableCopy] autorelease];
// Add new stuff.

NSMutableArray *myPhotos = [[NSMutableArray alloc] initWithCapacity:2];
[myPhotos addObject:@"Attribute 1"];
[myPhotos addObject:@"Attribute 2"];

[newContent setObject:myPhotos forKey:self.filePath];

// Now, write the plist:
[newContent writeToFile:plistPath atomically:YES];

Answer 1

你这样做：

// Get current content.
NSDictionary *oldContent = [NSDictionary dictionaryWithContentsOfFile:plistPath];
// Make a mutable copy.
NSMutableDictionary *newContent = [[oldContent mutableCopy] autorelease];
// Add new stuff.
[newContent setObject:newObject forKey:newKey];
// Now, write the plist:
[newContent writeToFile:plistPath atomically:YES];

此处无需使用NSPropertyListSerialization。

Answer 2

你有一个字典开头，

124818240124810284.JPG //[valueForKey: 124818240124810284.JPG] 



                    item 0          String     Some Attribute 1 //[valueForKey:124818240124810284.JPG] valueForKey:Item 0];
                    item 1          String     Some Attribute 2 //[valueForKey:124818240124810284.JPG] valueForKey:Item 1];


    354273577823597297.JPG    //[valueForKey: 354273577823597297.JPG]    
                    item 0          String     Some Attribute 1 //[valueForKey: 354273577823597297.JPG] valueForKey:Item 0];
                    item 1          String     Some Attribute 2 //[valueForKey: 354273577823597297.JPG] valueForKey:Item 1;

等等......要添加它，请使用新的值/密钥对创建一个新字典：

 NSMutableDictionary *newAttributes = [[NSMutableDictionary alloc]initWithObjectsAndKeys:@"Attribute 0",@"Item 0",nil];

制作一个新词典：

   NSMutableDictionary *newEntry = [[NSMutableDictionary alloc]initWithObjectsAndKeys:newAttributes,@"xxxxx.jpg", nil];//Makes a new dictionary

或者将数据附加到现有字典：

[dictionaryToAppend setValue:newAttribues ForKey:xxxxx.jpg"];

将数据附加到PLIST - iPhone

2 个答案: