将字符串保存到 NSUserDefaults 中？

Question

如何将字符串保存到NSUserDefaults中？

Answer 1

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

稍后取回

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

Answer 2

更准确地说

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

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

Answer 3

以下是如何使用 Swift 做同样的事情；

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

稍后取回；

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") {

}

Answer 4

像这样的事情：

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"];

您应该真正查看Apple的 NSUserDefaults 类参考，也许还有本教程： iPhone 编程教程 – 使用 NSUserDefaults 保存/检索数据

Answer 5

不要忘记这个声明，否则它可能并不总是有效：

[standardUserDefaults synchronize];

Answer 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];

检索中

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"];

Answer 7

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

Answer 8

一个好的做法是对密钥使用常量，以避免不使用同一密钥存储和读取的错误

NSString* const TIME_STAMPS_KEY = @"TIME_STAMPS_KEY";

Answer 9

在 Swift5 和 Xcode 10.2

//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（指字符串、数组、字典等）保存在 UserDefaults 中。

不要将图像保存在 UserDefaults 中，不推荐（将图像保存在本地目录中）。

Answer 10

-(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它：

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

使用以下方式检索字符串：

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

Answer 11

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"];
        }

    }
     }

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：     
      @“用户列表”]]；                                
  
  UIImage *ima = _imaGe.image;
  NSData *imagedata = UIImageJPEGRepresentation(ima,100);
  
  NSDictionary *dict = @{@"用户名":_userTxt.text,@"姓氏":_lastTxt.text,@"名字":_firstTxt.text,@"手机号码":_mobTxt.text,@"dob":_dobTxt.text ,@"图像":图像数据};
  
     [array2 addObject:dict];
    [[NSUserDefaults standardUserDefaults]setObject:array2    
    forKey:@"用户列表"];
     NSLog(@"%@",array2);
  
    [self PerformSegueWithIdentifier:@"第二个"发件人:self];
  
   }
  

  • (IBAction)chooseImg:(id)发件人{

    UIImagePickerController *picker = [[UIImagePickerController
    分配]初始化]；
    picker.delegate = self；
    picker.allowsEditing = YES;
    picker.sourceType =
    UIImagePickerControllerSourceTypePhotoLibrary；
    [self presentViewController:picker 动画: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; }

Answer 12

要保存，请使用此：

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

要检索，请使用此：

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

Answer 13

Swift 3 更新

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
}

Answer 14

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!

Answer 15

这里 Swift 更新了：

let userID = "BOB"  

声明 userDefaults:

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

并获取它：

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

Answer 16

在这里，对于 Swift，我创建了两个函数，它们将保存并从首选项中检索值。

这将对你有很大帮助。

// 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)!
}