Cocoa：如何将NSAttributedString保存为JSON

问题描述

我有一个 NSAttributedString 对象作为自定义对象的属性。我需要以 JSON 格式将此自定义对象保存到磁盘。后来我需要通过网络将这个JSON数据发送到Java服务器。

我不能使用 - （NSString）string NSSAttributedString 对象，因为我需要能够重建磁盘和服务器上的属性字符串。

解决方案

NSAttributedString有两个属性：

• 字符串






每个run都有：






• 一个整数范围适用于


• 键/值属性字典






使用 enumerateAttributesInRange：options：usingBlock：将很容易表示为JSON。





类似：

  {
string：Hello World，
runs ：[
 {
range：[0,3]，
attributes：{
font：{
name：Arial ，
size：12 
} 
} 
}，
 {
range：[3,6]，
属性：{
font：{
name：Arial，
size：12 
}，
color：[255 ，0,0] 
} 
}，
 {
range：[9,2]，
attributes：{
font ：{
name：Arial，
size：12 
} 
} 
} 
] 
} b $ b 

EDIT：这里是一个示例实现：



//创建基本属性字符串
NSMutableAttributedString * attStr = [[NSMutableAttributedString alloc] initWithString：@Hello World属性：@ {NSFontAttributeName： NSFont fontWithName：@Arialsize：12]}];
[attStr addAttribute：NSForegroundColorAttributeName value：[NSColor redColor] range：NSMakeRange（3，6）];

//构建属性运行数组
NSMutableArray * attributeRuns = [NSMutableArray array];
[attStr enumerateAttributesInRange：NSMakeRange（0，attStr.length）options：0 usingBlock：^（NSDictionary * attrs，NSRange range，BOOL * stop）{
NSArray * rangeArray = @ [[NSNumber numberWithUnsignedInteger：range .location]，
[NSNumber numberWithUnsignedInteger：range.length]];

NSMutableDictionary * runAttributes = [NSMutableDictionary dictionary];
[attrs enumerateKeysAndObjectsUsingBlock：^（id attributeName，id attributeValue，BOOL * stop）{

if（[attributeName isEqual：NSFontAttributeName]）{//将字体值转换为字典和size
attributeName = @font;
attributeValue = @ {@name：[（NSFont *）attributeValue displayName]，
@size：[NSNumber numberWithFloat：[（NSFont *）attributeValue pointSize]

} else if（[attributeName isEqualToString：NSForegroundColorAttributeName]）{//将前景颜色值转换为一个数字，将红/绿/蓝作为0到255的数字
attributeName = @颜色;
attributeValue = @ [[NSNumber numberWithInteger：（[NSColor *）attributeValue redComponent] * 255）]，
[NSNumber numberWithInteger：（[NSColor *）attributeValue greenComponent] * 255）]，
[NSNumber numberWithInteger：（[（NSColor *）attributeValue blueComponent] * 255）]];

} else {//跳过未知属性
NSLog（@跳过未知属性％@，attributeName）;
return;
}


[runAttributes setObject：attributeValue forKey：attributeName];
}];

//保存属性（如果有的话）
if（runAttributes.count == 0）
return;

[attributeRuns addObject：@ {@range：rangeArray，
@attributes：runAttributes}];
}];

// build JSON output
NSDictionary * jsonOutput = @ {@string：attStr.string，
@runs：attributeRuns};
NSData * jsonData = [NSJSONSerialization dataWithJSONObject：jsonOutput options：NSJSONWritingPrettyPrinted error：NULL];

NSLog（@％@，[[NSString alloc] initWithData：jsonData encoding：NSUTF8StringEncoding]）;
exit（0）;





I have a NSAttributedString object as a property of a custom object. I need to save this custom object to the disk in JSON format. Later I need to send this JSON data across the network to a Java Server.
I can't use the -(NSString) string method of the NSSAttributedString object because I need to be able to reconstruct the attributed string off the disk and on the server.

解决方案

NSAttributedString has two properties:

• the string
• an array of attribute "runs"

Each "run" has:

• an integer range that it applies to
• a dictionary of key/value attributes

It would be very easy to represent that as JSON, using enumerateAttributesInRange:options:usingBlock:.

Something like:

{
  "string" : "Hello World",
  "runs" : [
    {
      "range" : [0,3],
      "attributes" : {
        "font" : {
          "name" : "Arial",
          "size" : 12
        }
      }
    },
    {
      "range" : [3,6],
      "attributes" : {
        "font" : {
          "name" : "Arial",
          "size" : 12
        },
        "color" : [255,0,0]
      }
    },
    {
      "range" : [9,2],
      "attributes" : {
        "font" : {
          "name" : "Arial",
          "size" : 12
        }
      }
    }
  ]
}

EDIT: here's an example implementation:

// create a basic attributed string
NSMutableAttributedString *attStr = [[NSMutableAttributedString alloc] initWithString:@"Hello World" attributes:@{NSFontAttributeName: [NSFont fontWithName:@"Arial" size:12]}];
[attStr addAttribute:NSForegroundColorAttributeName value:[NSColor redColor] range:NSMakeRange(3, 6)];

// build array of attribute runs
NSMutableArray *attributeRuns = [NSMutableArray array];
[attStr enumerateAttributesInRange:NSMakeRange(0, attStr.length) options:0 usingBlock:^(NSDictionary *attrs, NSRange range, BOOL *stop) {
  NSArray *rangeArray = @[[NSNumber numberWithUnsignedInteger:range.location],
                          [NSNumber numberWithUnsignedInteger:range.length]];

  NSMutableDictionary *runAttributes = [NSMutableDictionary dictionary];
  [attrs enumerateKeysAndObjectsUsingBlock:^(id attributeName, id attributeValue, BOOL *stop) {

    if ([attributeName isEqual:NSFontAttributeName]) { // convert font values into a dictionary with the name and size
      attributeName = @"font";
      attributeValue = @{@"name": [(NSFont *)attributeValue displayName],
                         @"size": [NSNumber numberWithFloat:[(NSFont *)attributeValue pointSize]]};

    } else if ([attributeName isEqualToString:NSForegroundColorAttributeName]) { // convert foreground colour values into an array with red/green/blue as a number from 0 to 255
      attributeName = @"color";
      attributeValue = @[[NSNumber numberWithInteger:([(NSColor *)attributeValue redComponent] * 255)],
                         [NSNumber numberWithInteger:([(NSColor *)attributeValue greenComponent] * 255)],
                         [NSNumber numberWithInteger:([(NSColor *)attributeValue blueComponent] * 255)]];

    } else { // skip unknown attributes
      NSLog(@"skipping unknown attribute %@", attributeName);
      return;
    }


    [runAttributes setObject:attributeValue forKey:attributeName];
  }];

  // save the attributes (if there are any)
  if (runAttributes.count == 0)
    return;

  [attributeRuns addObject:@{@"range": rangeArray,
                             @"attributes": runAttributes}];
}];

// build JSON output
NSDictionary *jsonOutput = @{@"string": attStr.string,
                             @"runs": attributeRuns};
NSData *jsonData = [NSJSONSerialization dataWithJSONObject:jsonOutput options:NSJSONWritingPrettyPrinted error:NULL];

NSLog(@"%@", [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding]);
exit(0);

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