将字符串保存到NSUserDefaults？

时间：2010-06-19 05:33:38

标签： ios cocoa-touch nsuserdefaults

如何将字符串保存到NSUserDefaults？

16 个答案:

答案 0 :(得分：435)

NSString *valueToSave = @"someValue";
[[NSUserDefaults standardUserDefaults] setObject:valueToSave forKey:@"preferenceName"];
[[NSUserDefaults standardUserDefaults] synchronize];

稍后再回来

NSString *savedValue = [[NSUserDefaults standardUserDefaults]
    stringForKey:@"preferenceName"];

答案 1 :(得分：49)

更准确地说

-(void)saveToUserDefaults:(NSString*)myString
{
    NSUserDefaults *standardUserDefaults = [NSUserDefaults standardUserDefaults];

    if (standardUserDefaults) {
        [standardUserDefaults setObject:myString forKey:@"timestamps"];
        [standardUserDefaults synchronize];
    }
}

答案 2 :(得分：31)

以下是如何使用Swift做同样的事情; 

var valueToSave = "someValue"
NSUserDefaults.standardUserDefaults().setObject(valueToSave, forKey: "preferenceName")

稍后再回来; 

if let savedValue = NSUserDefaults.standardUserDefaults().stringForKey("preferenceName") {
    // Do something with savedValue
}

在Swift 3.0中 

var valueToSave = "someValue"
UserDefaults.standard.set(valueToSave, forKey: "preferenceName")

if let savedValue = UserDefaults.standard.string(forKey: "preferenceName") {

}

答案 3 :(得分：12)

这样的事情：

NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];

// saving an NSString
[prefs setObject:@"TextToSave" forKey:@"keyToLookupString"];

然后检索：

NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];

// getting an NSString
NSString *myString = [prefs stringForKey:@"keyToLookupString"];

您应该查看Apple的NSUserDefaults类参考，​​也可以查看本教程：iPhone Programming Tutorial – Saving/Retrieving Data Using NSUserDefaults

答案 4 :(得分：12)

不要忘记这句话，否则它可能并不总是有效：

[standardUserDefaults synchronize];

答案 5 :(得分：6)

[[NSUserDefaults standardUserDefaults] setValue:aString forKey:aKey]

答案 6 :(得分：6)

NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];

// saving an NSString
[prefs setObject:@"TextToSave" forKey:@"keyToLookupString"];

// saving an NSInteger
[prefs setInteger:42 forKey:@"integerKey"];

// saving a Double
[prefs setDouble:3.1415 forKey:@"doubleKey"];

// saving a Float
[prefs setFloat:1.2345678 forKey:@"floatKey"];

// This is suggested to synch prefs, but is not needed (I didn't put it in my tut)
[prefs synchronize];

检索

NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];

// getting an NSString
NSString *myString = [prefs stringForKey:@"keyToLookupString"];

// getting an NSInteger
NSInteger myInt = [prefs integerForKey:@"integerKey"];

// getting an Float
float myFloat = [prefs floatForKey:@"floatKey"];

答案 7 :(得分：5)

一个好的做法是使用密钥的常量来避免在不使用相同密钥存储和读取的错误

NSString* const TIME_STAMPS_KEY = @"TIME_STAMPS_KEY";

答案 8 :(得分：1)

-(void)saveToUserDefaults:(NSString*)string_to_store keys:(NSString *)key_for_the_String
{
    NSUserDefaults *standardUserDefaults = [NSUserDefaults standardUserDefaults];

    if (standardUserDefaults) {
        [standardUserDefaults setObject:string_to_store forKey:key_for_the_String];
        [standardUserDefaults synchronize];
    }
}

并通过以下方式调用：

[self saveToUserDefaults:@"string_to_store" : @"key_for_the_string"];

使用以下方法检索字符串：

NSString * stored_string = [[NSUserDefaults standardUserDefaults] stringforkey:key_for_the_String]

答案 9 :(得分：1)

<强>的firstView 

    {
    NSMutableArray *array; }
- (void)viewDidLoad {
    [super viewDidLoad];
    array = [[NSMutableArray alloc]init];
    array = [[NSUserDefaults  standardUserDefaults]objectForKey:@"userlist"];

     NSLog(@"%lu",(unsigned long)array.count);
    if (array>0)
    {
        for (int i=0; i<array.count; i++)
        {
            NSDictionary *dict1 = @{@"Username":[[array valueForKey:@"Username"] objectAtIndex:i],@"Mobilenumber":[[array valueForKey:@"Mobilenumber"] objectAtIndex:i],@"Firstname":[[array valueForKey:@"Firstname"] objectAtIndex:i],@"Lastname":[[array valueForKey:@"Lastname"] objectAtIndex:i],@"dob":[[array valueForKey:@"dob"] objectAtIndex:i],@"image":[[array valueForKey:@"image"] objectAtIndex:i]};
            NSLog(@"%@",dict1);
            NSArray *array1 = [[NSArray alloc]initWithObjects:dict1, nil];
            [[NSUserDefaults standardUserDefaults] setObject:array1 forKey:@"UserList"];
        }

    }
     }

<强> ImagePicker 

     - (void)imagePickerController:(UIImagePickerController *)picker         didFinishPickingMediaWithInfo:(NSDictionary *)info {

    UIImage *chosenImage = info[UIImagePickerControllerEditedImage];
    self.imaGe.image = chosenImage;

    [picker dismissViewControllerAnimated:YES completion:NULL];
     }

  • （IBAction）submitBton：（id）sender {

    NSMutableArray *array2 = [[NSMutableArray alloc]initWithArray: 
[[NSUserDefaults standardUserDefaults]objectForKey:     
    @"userlist"]];                                

UIImage *ima = _imaGe.image;
NSData *imagedata = UIImageJPEGRepresentation(ima,100);

NSDictionary *dict =  @{@"Username":_userTxt.text,@"Lastname":_lastTxt.text,@"Firstname":_firstTxt.text,@"Mobilenumber":_mobTxt.text,@"dob":_dobTxt.text,@"image":imagedata};

   [array2 addObject:dict];
  [[NSUserDefaults standardUserDefaults]setObject:array2    
  forKey:@"userlist"];
   NSLog(@"%@",array2);

  [self performSegueWithIdentifier:@"second" sender:self];

 }

    • （IBAction）chooseImg：（id）sender {

      UIImagePickerController * picker = [[UIImagePickerController
      alloc] init]; picker.delegate = self; picker.allowsEditing = YES; picker.sourceType =
      UIImagePickerControllerSourceTypePhotoLibrary; [self presentViewController：动画选择器：YES完成：NULL];

      }

第二个视图 {         NSMutableArray * arr; } 

- (void)viewDidLoad {
    [super viewDidLoad];

     arr =[[NSMutableArray alloc]init];
    arr = [[NSUserDefaults standardUserDefaults]objectForKey:@"userlist"]; }

#pragma mark- TableView DataSource

-(NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
    return 1; }

-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    return arr.count; }

-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    static NSString *cellId = @"tablecell";
    TableViewCell *cell =[tableView dequeueReusableCellWithIdentifier:cellId];
    cell.userLbl.text =[[arr valueForKey:@"username"] objectAtIndex:indexPath.row];
    cell.ageLbl.text =[[arr valueForKey:@"dob"] objectAtIndex:indexPath.row];
    cell.profileImg.image =[UIImage imageNamed:[[arr valueForKey:@"image"] objectAtIndex:indexPath.row]];
    return cell; }

答案 10 :(得分：1)

在Swift 4.0.3 Xcode 9中 

============set  Data in UserDefaults =========

  UserDefaults.standard.set(userName, forKey: "userName")
  UserDefaults.standard.synchronize()

============Get Data in UserDefaults =========

  let userName = UserDefaults.standard.string(forKey: "userName")
  print(userName ?? "Gera")

  userNameTextField.text = ""+userName!

答案 11 :(得分：1)

在 Swift5 和Xcode 10.2

中 
//Save
UserDefaults.standard.set(true, forKey: "Key1") //Bool
UserDefaults.standard.set(1, forKey: "Key2")  //Integer
UserDefaults.standard.set("This is my string", forKey: "Key3") //String
UserDefaults.standard.synchronize()

//Retrive
UserDefaults.standard.bool(forKey: "Key1")
UserDefaults.standard.integer(forKey: "Key2")
UserDefaults.standard.string(forKey: "Key3")

//Remove
UserDefaults.standard.removeObject(forKey: "Key3")

注意：将文本数据（表示字符串，数组，字典等）保存在UserDefaults中。不要将图像保存在UserDefaults中，不建议（将图像保存在本地目录中）。

答案 12 :(得分：0)

为了节省使用： 

[[NSUserDefaults standardUserDefaults]setObject:@"YES" forKey:@"KTerminated"];
[[NSUserDefaults standardUserDefaults]synchronize];

对于Retriveing使用此： 

[[[NSUserDefaults standardUserDefaults]stringForKey:@"KTerminated"] isEqualToString:@"YES"];

答案 13 :(得分：0)

这里对于Swift，我创建了两个函数，它从Preference

中调用key的save和retrive值

可能这对你来说是完全有用的

//用于保存对象

static func setObject(value:AnyObject ,key:String)
{
    let pref = NSUserDefaults.standardUserDefaults()
    pref.setObject(value, forKey: key)
    pref.synchronize()
}

static func getObject(key:String) -> AnyObject
{
    let pref = NSUserDefaults.standardUserDefaults()
    return pref.objectForKey(key)!
}

答案 14 :(得分：0)

更新Swift 3 

func setObject(value:AnyObject ,key:String)
{
    let pref = UserDefaults.standard
    pref.set(value, forKey: key)
    pref.synchronize()
}

func getObject(key:String) -> AnyObject
{
    let pref = UserDefaults.standard
    return pref.object(forKey: key)! as AnyObject
}

答案 15 :(得分：0)

这里 Swift 更新了：

let userID = "BOB"

声明用户默认值：

let defaults = UserDefaults.standard
defaults.setValue(userID, forKey: "userID")

得到它：

let userID = defaults.object(forKey: "userID")
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