[英]Retrieving data from NSUserDefaults - works in one view but fails in another
我使用下面的代碼(來自AppDelegate文件)將登錄的Facebook用戶名保存到NSUserDefaults首選項。 代碼檢索用戶名並將其輸出到控制台就好了。 當我嘗試在另一個視圖控制器中執行相同的操作時,NSLog輸出返回(null)。
我錯過了什么? 謝謝你的幫助。
- (void)request:(FBRequest *)request didLoad:(id)result {
if ([result isKindOfClass:[NSDictionary class]]) {
NSDictionary* hash = result;
NSString *username = (NSString*)[hash valueForKey:@"name"];
[[NSUserDefaults standardUserDefaults] setObject:username forKey:@"Username"];
NSLog(@"%@", username);
NSUserDefaults * standardUserDefaults = [NSUserDefaults standardUserDefaults];
NSString *user = [standardUserDefaults stringForKey:@"Username"];
NSLog(@"username from user defs %@",user);
}
};
這是來自其他視圖控制器的代碼不起作用:
NSUserDefaults * standardUserDefaults = [NSUserDefaults standardUserDefaults];
NSString *user = [standardUserDefaults stringForKey:@"Username"];
NSLog(@"username from user defs %@",user);
userNameLbl.text = user;
這是日志輸出:
username from user defs app delegate my Facebook name
2012-03-30 13:29:20.564 project V2[63339:15803] (null)
2012-03-30 13:29:20.565 project V2[63339:15803] username from user defs app delegate (null)
2012-03-30 13:29:28.620 project V2[63339:15803] username from user defs (null)
NSUserDefaults * standardUserDefaults = [NSUserDefaults standardUserDefaults];
NSString *user = [[NSUserDefaults standardUserDefaults] stringForKey:@"Username"];
NSLog(@"username from user defs %@",user);
userNameLbl.text = user;
試試這個(我換了一行)
NSString *user = [[NSUserDefaults standardUserDefaults] stringForKey:@"Username"];
編輯這是我如何將東西保存到NSUserDefaults;
NSString *theKeyIWantToSave;
NSUSerDefaults *defaults=[NSUserDefaults standardUserDefaults];
[defaults setObject:theKeyIWantToSave forKey:@"SomeKey"];
無論什么/我想要檢索它
NSString *key=[[NSUserDefaults standardUserDefaults] objectForKey:@"SomeKey"];
嘗試:
[[NSUserDefaults standardUserDefaults] setValue:newStr forKey:@"Username"];
用於設置和:
[[NSUserDefaults standardUserDefaults] valueForKey:@"Username"];
得到它。 沒有進口,沒有!
一個常見的錯誤是忘記或不知道保存默認值。呼叫:
[[NSUserDefaults standardUserDefaults] synchronize];
這會將您的默認值寫入文件,以便您下次檢索它們。
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