Question

我尝试在NSMutableArray 中添加NSUserDefault，但它总是重新调整为空。 我知道。所以我甚至创建了一个可变复制的os数组，但仍然。

NSUserDefaults返回的值即使你设置了一个，也是不可变的可变对象作为值。对于例如，如果您设置了一个可变字符串作为＆＃34; MyStringDefault＆＃34;的值，您稍后使用的字符串 stringForKey：将是不可变的。

 NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];
NSMutableArray *myStoredEvents=[prefs objectForKey:@"MySavedEvents"];

NSMutableArray *myStoredEventsNew=[[NSMutableArray alloc]init];
myStoredEventsNew=myStoredEvents;
NSMutableArray *tempDic=[myevents objectAtIndex:eventId];//myevents a NSMutableArray

if(myStoredEventsNew != nil)
{
    [myStoredEventsNew insertObject:tempDic atIndex:0];
}
else
{
    [myStoredEventsNew insertObject:tempDic atIndex:myStoredEvents.count];
 }
NSLog(@"New dictonary before modification :%@",tempDic);
[prefs setObject:myStoredEventsNew forKey:@"MySavedEvents"];
[prefs synchronize];

Answer 1

试试这段代码 -

NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];
    NSLog(@"DEBUG :: %@",[prefs objectForKey:@"MySavedEvents"]);
    NSMutableArray *myStoredEvents;
    if ([prefs objectForKey:@"MySavedEvents"] == NULL) {
        myStoredEvents  =   [[NSMutableArray alloc]init];
    }else{
        myStoredEvents=[[prefs objectForKey:@"MySavedEvents"] mutableCopy];
    }
    NSMutableArray *tempDic=[myevents objectAtIndex:eventId];//myevents a NSMutableArray

    [myStoredEvents addObject:tempDic];

    NSLog(@"New dictonary before modification :%@",myStoredEvents);
    [prefs setObject:myStoredEvents forKey:@"MySavedEvents"];
    [prefs synchronize];

这可以解决你的问题

Answer 2

您可以在NSuserdefaults中保存数组，如下所示： -

[[NSUserDefaults standardUserDefaults] setObject:yourArray forKey:@"MySavedEvents"];
[[NSUserDefaults standardUserDefaults] synchronize];

您可以将检查条件设置为检查NSuserdefault，如下所示： -

NSObject * object = [prefs objectForKey:@"MySavedEvents"];
if(object != nil){
   //object is there
}

您可以根据需要提出更多条件，这只是如何实现这一目标的基本结构。

NSMutableArry没有被添加到NSuserdefaults中

2 个答案: