如何在 NSUserDefaults 中存储自定义对象
how can store custom objects in NSUserDefaults
对于重复的问题,我深表歉意。我是 ios 的新人。我想将自定义对象存储在 userdefaults 中。我正在使用 objective-c 。
提前致谢
首先你创建自定义 class 如下所示。
CustomObject.h
#import <Foundation/Foundation.h>
@interface CustomObject : NSObject<NSCoding>
@property(strong,nonatomic)NSString *name;
@end
CustomObject.m
#import "CustomObject.h"
@implementation CustomObject
- (void)encodeWithCoder:(NSCoder *)encoder {
//Encode properties, other class variables, etc
[encoder encodeObject:self.name forKey:@"name"];
}
- (id)initWithCoder:(NSCoder *)decoder {
if((self = [super init])) {
//decode properties, other class vars
self.name = [decoder decodeObjectForKey:@"name"];
}
return self;
}
然后创建 CustomObject class 对象并存储在 NSUserDefaults
像这样存储你的对象
CustomObject *object =[CustomObject new];
object.name = @"test";
NSMutableArray *arr = [[NSMutableArray alloc]init];
[arr addObject:object];
NSData *encodedObject = [NSKeyedArchiver archivedDataWithRootObject:arr];
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
[defaults setObject:encodedObject forKey:@"storeObject"];
[defaults synchronize];
像这样从 NSUserDefaults 获取自定义对象
NSData *storedEncodedObject = [defaults objectForKey:@"storeObject"];
NSArray *arrStoreObject = [NSKeyedUnarchiver unarchiveObjectWithData:storedEncodedObject];
for (int i=0; i<arrStoreObject.count; i++)
{
CustomObject *storedObject = [arrStoreObject objectAtIndex:i];
NSLog(@"%@",storedObject.name);
}
在Swift3
// set a value for key
let encodedData = NSKeyedArchiver.archivedData(withRootObject: #YOUR OBJECT#)
UserDefaults.standard.set(encodedData, forKey: #YOUR KEY#)
// retrieving a value for a key
if let data = UserDefaults.standard.data(forKey: #YOUR KEY#),
let obj = NSKeyedUnarchiver.unarchiveObject(with: data) as? #YOUR OBJECT# {
} else {
print("There is an issue")
}
对于重复的问题,我深表歉意。我是 ios 的新人。我想将自定义对象存储在 userdefaults 中。我正在使用 objective-c 。
提前致谢
首先你创建自定义 class 如下所示。
CustomObject.h
#import <Foundation/Foundation.h>
@interface CustomObject : NSObject<NSCoding>
@property(strong,nonatomic)NSString *name;
@end
CustomObject.m
#import "CustomObject.h"
@implementation CustomObject
- (void)encodeWithCoder:(NSCoder *)encoder {
//Encode properties, other class variables, etc
[encoder encodeObject:self.name forKey:@"name"];
}
- (id)initWithCoder:(NSCoder *)decoder {
if((self = [super init])) {
//decode properties, other class vars
self.name = [decoder decodeObjectForKey:@"name"];
}
return self;
}
然后创建 CustomObject class 对象并存储在 NSUserDefaults
像这样存储你的对象
CustomObject *object =[CustomObject new];
object.name = @"test";
NSMutableArray *arr = [[NSMutableArray alloc]init];
[arr addObject:object];
NSData *encodedObject = [NSKeyedArchiver archivedDataWithRootObject:arr];
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
[defaults setObject:encodedObject forKey:@"storeObject"];
[defaults synchronize];
像这样从 NSUserDefaults 获取自定义对象
NSData *storedEncodedObject = [defaults objectForKey:@"storeObject"];
NSArray *arrStoreObject = [NSKeyedUnarchiver unarchiveObjectWithData:storedEncodedObject];
for (int i=0; i<arrStoreObject.count; i++)
{
CustomObject *storedObject = [arrStoreObject objectAtIndex:i];
NSLog(@"%@",storedObject.name);
}
在Swift3
// set a value for key
let encodedData = NSKeyedArchiver.archivedData(withRootObject: #YOUR OBJECT#)
UserDefaults.standard.set(encodedData, forKey: #YOUR KEY#)
// retrieving a value for a key
if let data = UserDefaults.standard.data(forKey: #YOUR KEY#),
let obj = NSKeyedUnarchiver.unarchiveObject(with: data) as? #YOUR OBJECT# {
} else {
print("There is an issue")
}