CoreData应用程序在执行获取请求时冻结请求pthread_mutex_lock [英] CoreData Application Freezes while performing a fetch Request pthread_mutex_lock

问题描述

我使用Core Data来管理我的应用程式中的资料库。

I am using Core Data for managing data base into my app.

我无法在这里发布代码，因为它太长。但我想我可以解释我的问题在小行代码以及一些快照。

I can not post the code here, because its too lengthy. But I guess that I can explain my problem in small line of code along with some snap shots.

+(NSArray *)checkusernameandpassword:(NSString *)entityname  username:(NSString *)username   password:(NSString *)password 
{
    managedobjectcontext=[Singleton sharedmysingleton].managedobjectcontext;
    NSEntityDescription *entity=[NSEntityDescription entityForName:entityname inManagedObjectContext:managedobjectcontext];

    NSFetchRequest *request=[[NSFetchRequest alloc] init];
    [request setEntity:entity];

    NSPredicate *predicates=[NSPredicate predicateWithFormat:[NSString stringWithFormat:@"userName==\"%@\" AND password==\"%@\"",username,password]];
    [request setPredicate:predicates];  
    //On Below line, My app frezes and goes into deadlock, this happens randomly while performing
    //some data request using Core data
    NSArray *arrayofrecord=[managedobjectcontext executeFetchRequest:request error:nil];    

    return arrayofrecord;
}

我试图附加一些屏幕截图看到我暂停我的应用程序）
在图像中出现死锁的方法如上所述

推荐答案

你必须锁定线程。当多个线程访问同一段代码时，会出现此问题。但是不要最终进入死锁。

You have to lock the thread. This problem appears when multiple threads access the same piece of code. But be were not to end up in to a dead lock.

static NSString *fetchRequest = @"fetchRequest";
    NSArray *results;
    @synchronized (fetchRequest){
        managedobjectcontext=[Singleton sharedmysingleton].managedobjectcontext;
        NSEntityDescription *entity=[NSEntityDescription entityForName:entityname inManagedObjectContext:managedobjectcontext];

        NSFetchRequest *request=[[NSFetchRequest alloc] init];
       [request setEntity:entity];

       NSPredicate *predicates=[NSPredicate predicateWithFormat:[NSString stringWithFormat:@"userName==\"%@\" AND password==\"%@\"",username,password]];
       [request setPredicate:predicates];  
       //On Below line, My app frezes and goes into deadlock, this happens randomly while performing
       //some data request using Core data
       results = [managedobjectcontext executeFetchRequest:request error:nil];    
}
return results;

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