的Objective-C：寫的.plist中值數組的特定索引

Question

我明白我可以例如值寫入一個文件的.plist這樣

NSString *filePath = [[NSBundle mainBundle] pathForResource:@"stored" ofType:@"plist"]; 
NSString *comment = @"this is a comment"; 
[comment writeToFile:filePath atomically:YES]; 

，但如果我有發言權的數組在我的.plist（gameArray）中，並且我想將comment變成我陣列的特定索引，即gameArray[4];我將如何做到這一點？

讓我澄清

• 我有一個plist中：stored.plist
• 我的plist裏面有一個數組gameArray
• 我想更新的plist 內的gameArray具體指標這是可能的？

Answer 1

假設「stored.plist」的內容是一個數組，你需要實例從路徑上的可變數組：

NSString *filePath = [[NSBundle mainBundle] pathForResource:@"stored" ofType:@"plist"]; 
NSMutableArray *array = [NSMutableArray arrayWithContentsOfFile:filePath]; 
NSString *comment = @"this is a comment"; 

// inserting a new object: 
[array insertObject:comment atIndex:4]; 

// replacing an existing object: 
// classic obj-c syntax 
[array replaceObjectAtIndex:4 withObject:4];   
// obj-c literal syntax: 
array[4] = comment; 

// Cannot save to plist inside your document bundle. 
// Save a copy inside ~/Library/Application Support 

NSURL *documentsURL = [[[NSFileManager defaultManager] URLsForDirectory:NSApplicationSupportDirectory inDomains:NSUserDomainMask] objectAtIndex:0]; 
NSURL *arrayURL = [documentsURL URLByAppendingPathComponent:[filePath lastPathComponent]]; 
[array writeToURL:arrayURL atomically:NO]; 

Answer 2

無法更新和保存應用程序的主包數據，而不是你有在文件目錄或其他目錄下這樣做：

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

if([[NSFileManager defaultManager] fileExistsAtPAth:plistFilePath]) 
{//already exits 

    NSMutableArray *data = [NSMutableArray arrayWithContentsOfFile:plistFilePath]; 
    //update your array here 
    NSString *comment = @"this is a comment"; 
    [data replaceObjectAtIndex:4 withObject:comment]; 

    //write file here 
    [data writeToFile:plistFilePath atomically:YES]; 
} 
else{ //firstly take content from plist and then write file document directory 

NSString *plistPath = [[NSBundle mainBundle] pathForResource:@"stored" ofType:@"plist"]; 
NSMutableArray *data = [NSMutableArray arrayWithContentsOfFile:plistPath]; 
//update your array here 
    NSString *comment = @"this is a comment"; 
    [data replaceObjectAtIndex:4 withObject:comment]; 

    //write file here 
    [data writeToFile:plistFilePath atomically:YES]; 
}