寫給plist但是當我退出模擬時它是空的

嗨我實現了這個對象PlistManager來寫/讀plist在我的項目中。問題是plist被填充好會運行（我希望），當進入後臺（I使用通知和NSlog [Plistmanager readPlist：@「Database」]）我仍然可以讀取之前輸入的數據。寫給plist但是當我退出模擬時它是空的

問題是當我停止對xcode的模擬並再次運行時，plist現在是空的。爲什麼？

@interface ReadWritePlist : NSObject 
+(void)writeToPlist:(NSString*)filePlist dic:(NSDictionary*)dic; 
+ (NSMutableDictionary *)readPlist:(NSString*)filePlist; 

@end 

@implementation ReadWritePlist 


+ (void)writeToPlist:(NSString*)filePlist dic:(NSDictionary*)dic 
{ 

    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); 
    NSString *documentsDirectory = [paths objectAtIndex:0]; 

    [dic writeToFile:[documentsDirectory stringByAppendingPathComponent:[NSString stringWithFormat:@"%@.plist",filePlist]] atomically:YES]; 

} 


+ (NSMutableDictionary *)readPlist:(NSString*)filePlist { 

    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); 
    NSString *documentsDirectory = [paths objectAtIndex:0]; 
    NSString *filePath = [[documentsDirectory stringByAppendingPathComponent:filePlist] stringByAppendingPathExtension:@"plist"]; 
    NSMutableDictionary *dic=[[NSMutableDictionary alloc] initWithContentsOfFile:filePath]; 

    return dic; 
}

解決

我剛剛發現這些新的方法進行讀/寫plist中，它是working.I必須添加里面的appdelegate的「initializeFileDic」方法（didFinishLaunchingWithOptions）：

@implementation PlistManager 

+ (NSMutableDictionary *)readPlist:(NSString*)filePlist { 

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); 
NSString *documentsDirectory = [paths objectAtIndex:0]; 
NSString *filePath = [[documentsDirectory stringByAppendingPathComponent:filePlist] stringByAppendingPathExtension:@"plist"]; 
NSMutableDictionary *dic=[[NSMutableDictionary alloc] initWithContentsOfFile:filePath]; 

return dic; 
} 




+ (void)writeToPlist:(NSString*)filePlist dic:(NSDictionary*)dic 
{ 

    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); 
NSString *documentsDirectory = [paths objectAtIndex:0]; 

    if ([dic writeToFile:[documentsDirectory stringByAppendingPathComponent:[NSString stringWithFormat:@"%@.plist",filePlist]] atomically:YES]) { 
    NSLog(@"Ok done!"); 
    } 
    else{ 
      NSLog(@"Noo not done!"); 
    } 
} 

+ (void)initializeFileDic:(NSString*)FileNameExt 
{ 
    NSString *path = [[NSBundle mainBundle] bundlePath]; 
    NSString *startPath = [[path stringByAppendingPathComponent:FileNameExt]stringByAppendingPathExtension:@"plist"] ; 
    NSString *documentsDirectoryPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0]; 
    NSString *filePath = [[documentsDirectoryPath stringByAppendingPathComponent:FileNameExt]stringByAppendingPathExtension:@"plist"]; 

    NSLog(@"%@ \n,\n %@ ",startPath,filePath); 
    if([NSDictionary dictionaryWithContentsOfFile: startPath]){ 
    NSLog(@"File %@ exists",filePath); 
    } 
    if (![[NSFileManager defaultManager] fileExistsAtPath:filePath]){ 
     if([[NSDictionary dictionaryWithContentsOfFile:startPath] writeToFile:filePath atomically:NO]) 
     NSLog(@"File copied inside App DocumentsDirectory\n\n"); 
    else 
     NSLog(@"Error while trying to copy into DocumentsDirectory\n\n"); 
    } 

} 


@end

有人可以解釋什麼是錯？謝謝

來源

2012-05-25 luca

您是否知道NSDictionary的[writeToFile方法]（http://developer.apple.com/library/ios/documentation/Cocoa/Reference/Foundation/Classes/NSDictionary_Class/Reference/Reference.html#// apple_ref/occ/instm/NSDictionary/writeToFile：atomically :)返回成功結果？檢查是否爲YES或NO。另外，你在你的字典中記錄什麼類型的東西？這些項目中的任何一個是否定製了Objective C對象？ –

你使用ARC嗎？ – CarlJ

positive ..爲什麼你問我？ – luca

你什麼時候打電話把數據保存到plist？如果您從Xcode退出應用程序，那麼它會立即終止，並且不會通過任何與終止或輸入背景有關的應用程序委託方法，這是我懷疑您的代碼的地方。

按下模擬器上的home按鈕是獲取這些方法運行的方法。

來源

2012-05-25 06:41:00 jrturton

寫給plist但是當我退出模擬時它是空的

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