Question

在下面的代码中，我从URL获取数据并直接将其存储到TextFields。但是，当我的应用程序长时间进入后台并且我从暂停状态重新打开时，数据会丢失。

有没有人知道如何在NSUserDefaults中获取和存储数据，所以我不会丢失它，然后在文本字段中显示它？

- (void)viewDidLoad {

    [super viewDidLoad];

    NSMutableURLRequest *request=[NSMutableURLRequest requestWithURL:[NSURL URLWithString:@"http://190.179.4.9:92/mybite_joomla/cron/webapi.php?task=webapi.viewProfile"]];

    [request setHTTPMethod:@"GET"];

    [request setValue:@"application/json;charset=UTF-8" forHTTPHeaderField:@"content-type"];

    NSError *err;
    NSURLResponse *response;
    NSData *responseData = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&err];

    NSDictionary *jsonArray = [NSJSONSerialization JSONObjectWithData:responseData options: NSJSONReadingMutableContainers error: &err];

    for (NSDictionary *dict in jsonArray) {

        // here I am directly setting it into textfields and I need to store it first
        nameTextView.text =[jsonArray valueForKey:@"name"];   

        usernameTextView.text =[jsonArray valueForKey : @"username"];

        emailTextView.text=[jsonArray valueForKey : @"email"];

        cityTextView.text =[jsonArray valueForKey : @"city"];

        stateTextView.text =[jsonArray valueForKey : @"state"];

        countryTextView.text =[jsonArray valueForKey : @"country"];
    }
}

Answer 1

商店：

NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
[defaults setValue:nameTextView.text forKey:@"name"];
[defaults synchronize];

得到：

NSString *value = [[NSUserDefaults standardUserDefaults] stringForKey:@"name"];

Answer 2

首先获取NSUserDefaults的实例：

NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];

然后你可以存储数据：

NSString *name =[jsonArray valueForKey:@"name"];

[defaults setObject:name forKey:@"name"];
[defaults synchronize];

获取数据：

NSString *storedName = [defaults stringForKey:@"name"];

nameTextView.text = storedName;

Answer 3

for (NSDictionary *dict in jsonArray) {

[[NSUserDefaults standardUserDefaults]setObject:[jsonArray valueForKey:@"name"] forKey:@"nameString"];

[[NSUserDefaults standardUserDefaults]setObject:[jsonArray valueForKey:@"username"] forKey:@"usernameString"];

[[NSUserDefaults standardUserDefaults]setObject:[jsonArray valueForKey:@"email"] forKey:@"emailString"];

[[NSUserDefaults standardUserDefaults]setObject:[jsonArray valueForKey:@"city"] forKey:@"cityString"];

[[NSUserDefaults standardUserDefaults]setObject:[jsonArray valueForKey:@"state"] forKey:@"stateString"];

[[NSUserDefaults standardUserDefaults]setObject:[jsonArray valueForKey:@"country"] forKey:@"countryString"];

    }

然后，在viewWillAppear中：

    nameTextView.text = [[NSUserDefaults standardUserDefaults] stringForKey:@"nameString"];

    usernameTextView.text = [[NSUserDefaults standardUserDefaults] stringForKey:@"usernameString"];

    emailTextView.text = [[NSUserDefaults standardUserDefaults] stringForKey:@"emailString"];

    cityTextView.text = [[NSUserDefaults standardUserDefaults] stringForKey:@"cityString"];

    stateTextView.text = [[NSUserDefaults standardUserDefaults] stringForKey:@"stateString"];

    countryTextView.text = [[NSUserDefaults standardUserDefaults] stringForKey:@"countryString"];

如何使用从URL获取的NSUserDefaults存储数据并将它们设置为textFields

3 个答案: