cocoa read xml and save xml

发布时间：2020-12-16 09:39:01 所属栏目：百科来源：网络整理

导读：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

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：

@interfaceClientDisplayMgr{
…
IBOutletidm_clientName;//outletstotextboxesinthepreferences
IBOutletidm_serverName;//window.
NSArray*m_availableFriends;
…
}
@end
//
//Savesomevariouspreferences
-writePrefs
{
NSMutableDictionary*prefs;
//allocateanNSMutableDictionarytoholdourpreferencedata
prefs=[[NSMutableDictionaryalloc]init];
//ourpreferencedataisourclientname,hostname,andbuddylist
[prefssetObject:[m_clientNamestringValue]forKey:@"Client"];
[prefssetObject:[m_serverNamestringValue]forKey:@"Server"];
[prefssetObject:m_friendsforKey:@"Friends"];
//saveourbuddylisttotheuser'shomedirectory/Library/Preferences.
[prefswriteToFile:[@"~/Library/Preferences/MiniMessageClient.plist"
stringByExpandingTildeInPath]atomically:TRUE];
returnself;
}

保存下来的结果看起来是这样的：

<?xmlversion="1.0"encoding="UTF-8"?>
<!DOCTYPEplistSYSTEM"file://localhost/System/Library/DTDs/PropertyList.dtd">
<plistversion="0.9">
<dict>
<key>Client</key>
<string>CrazyJoe</string>
<key>Friends</key>
<array>
<string>CrazyJoe</string>
<string>Jim</string>
<string>Joe</string>
<string>CrazyJim</string>
<string>Jose</string>
<string>CrazyJoe</string>
</array>
<key>Server</key>
<string>localhost</string>
</dict>
</plist>

要想把保存的列表文件读取出来也很简单：

-awakeFromNib
{
NSString*clientName,*serverName;
NSDictionary*prefs;
//loadthepreferencesdictionary
prefs=[NSDictionarydictionaryWithContentsOfFile:
[@"~/Library/Preferences/MiniMessageClient.plist"
stringByExpandingTildeInPath]];
//ifthefilewasthere,wegotalltheinformationweneed.
//(notethatit'sprobablyagoodideatoindividuallyverifyobjects
//wepulloutofthedictionary,butthisisexamplecode
if(prefs){
//
//writeourloadednamesintothepreferencedialog'stextboxes.
[m_clientNamesetStringValue:[prefsobjectForKey:@"Client"]];
[m_serverNamesetStringValue:[prefsobjectForKey:@"Server"]];
//
//loadourfriendlist.
m_friends=[[prefsobjectForKey:@"Friends"]retain];
}else{
//
//nopropertylist.Thenibfile'sgotdefaultsforthe
//preferencedialogbox,butwestillneedalistoffriends.
m_friends=[[NSMutableArrayalloc]init];
//we'reouronlyfriend(isn'titstrangetalkingaboutweinthesingular?)
[m_friendsaddObject:[m_clientNamestringValue]];
}
//
//getourpreferencedatafortherestofawakeFromNib
clientName=[m_clientNamestringValue];
serverName=[m_serverNamestringValue];
…

My test

Save:

//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;

}

（编辑：李大同）

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