使用Cocoa保存XML格式记录文件是本文要介绍的内容，在Cocoa中保存XML的属性列表文件（plist）是很容易的事情。NSArray，NSDictionary,NSString,或者 NSData都可以保存为XML格式的plist文件。如果NSArray或者NSDictionary中还包含其他可以保存为属性列表的对象，它们可以一起存储在plist文件中。

下面是保存的方法：

1. @interfaceClientDisplayMgr{
2. …
3. IBOutletidm_clientName;//outletstotextBoxesinthepreferences
4. IBOutletidm_serverName;//window.
5. NSArray*m_availableFriends;
6. …
7. }
8. @end
10. //
11. //SavesomevarIoUspreferences
12. -writePrefs
13. {
14. NSMutableDictionary*prefs;
16. //allocateanNSMutableDictionarytoholdourpreferencedata
17. prefs=[[NSMutableDictionaryalloc]init];
19. //ourpreferencedataisourclientname,hostname,andbuddylist
20. [prefssetObject:[m_clientNamestringValue]forKey:@"Client"];
21. [prefssetObject:[m_serverNamestringValue]forKey:@"Server"];
22. [prefssetObject:m_friendsforKey:@"Friends"];
24. //saveourbuddylisttotheuser'shomedirectory/Library/Preferences.
25. [prefswriteToFile:[@"~/Library/Preferences/MiniMessageClient.plist"
26. stringByExpandingTildeInPath]atomically:TRUE];
27. returnself;
28. }
@H_301_81@

保存下来的结果看起来是这样的：

1. <?xmlversion="1.0"encoding="UTF-8"?>
2. <!DOCTYPEplistSYSTEM"file://localhost/System/Library/DTDs/PropertyList.dtd">
3. <plistversion="0.9">
4. <dict>
5. <key>Client</key>
6. <string>CrazyJoe</string>
7. <key>Friends</key>
8. <array>
9. <string>CrazyJoe</string>
10. <string>Jim</string>
11. <string>Joe</string>
12. <string>CrazyJim</string>
13. <string>Jose</string>
14. <string>CrazyJoe</string>
15. </array>
16. <key>Server</key>
17. <string>localhost</string>
18. </dict>
19. </plist>
@H_301_81@

要想把保存的列表文件读取出来也很简单：

1. -awakeFromNib
2. {
3. NSString*clientName,*serverName;
4. NSDictionary*prefs;
6. //loadthepreferencesdictionary
7. prefs=[NSDictionarydictionaryWithContentsOfFile:
8. [@"~/Library/Preferences/MiniMessageClient.plist"
9. stringByExpandingTildeInPath]];
11. //ifthefilewasthere,wegotalltheinformationweneed.
12. //(notethatit'sprobablyagoodideatoindividuallyverifyobjects
13. //wepulloutofthedictionary,butthisisexamplecode
14. if(prefs){
15. //
16. //writeourloadednamesintothepreferencedialog'stextBoxes.
17. [m_clientNamesetStringValue:[prefsobjectForKey:@"Client"]];
18. [m_serverNamesetStringValue:[prefsobjectForKey:@"Server"]];
20. //
21. //loadourfriendlist.
22. m_friends=[[prefsobjectForKey:@"Friends"]retain];
23. }else{
24. //
25. //nopropertylist.Thenibfile'sgotdefaultsforthe
26. //preferencedialogBox,butwestillneedalistoffriends.
27. m_friends=[[NSMutableArrayalloc]init];
28. //we'reouronlyfriend(isn'titstrangetalkingaboutweinthesingular?)
29. [m_friendsaddObject:[m_clientNamestringValue]];
30. }
32. //
33. //getourpreferencedatafortherestofawakeFromNib
34. clientName=[m_clientNamestringValue];
35. serverName=[m_serverNamestringValue];
36. …
@H_301_81@
My test @H_823_403@
Save: @H_823_403@
//test OK!
-(void) writePrefs_test
{
id m_clientName; // outlets to text Boxes in the preferences
id m_serverName; // window.
NSMutableDictionary * prefs;
NSString *aa=@"1243";
m_clientName = aa.copy;
NSString *aa_value;
aa_value = m_clientName;
// allocate an NSMutableDictionary to hold our preference data
prefs = [[NSMutableDictionary alloc] init];
// our preference data is our client name,and buddy list
//Save:
// [prefs setObject:m_clientName forKey:@"Client1"];
NSArray *classdata1 = [[NSArray alloc] initWithObjects:@"124c","name1",@"22",nil];
[prefs setObject:classdata1 forKey:@"ID1"];
NSArray *classdata2 = [[NSArray alloc] initWithObjects:@"124a","name2",@"11",nil];
[prefs setObject:classdata2 forKey:@"ID2"];
NSArray *classdata3 = [[NSArray alloc] initWithObjects:@"1244","name3",nil];
[prefs setObject:classdata3 forKey:@"ID3"];
NSFileManager *manager = [NSFileManager defaultManager];


NSArray *path = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask,YES);
NSString *documents = [path objectAtIndex:0];
NSString *filepath = [documents stringByAppendingPathComponent:@"a.plist"];


if([manager createFileAtPath:filepath contents:nil attributes:nil])
{
printf("文件创建成功");
}
else
{
printf("创建失败");
}
// save our buddy list to the user's home directory/Library/Preferences.
BOOL bSaved;
bSaved =[prefs writeToFile:[filepath
stringByExpandingTildeInPath] atomically: TRUE];
// BOOL bSaved;
// bSaved = [prefs writeToFile:[filepath
// stringByExpandingTildeInPath] atomically: YES];




if(TRUE == bSaved)
{
printf("Save ok! %d",bSaved);
}
else
{
printf("Save Failed! %d",bSaved);
}
// return self;
}
@H_823_403@
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