如何从NSUserDefaults读取字符串

Question

我在plist的根目录下有一个对象,它存储对象和键(其中一个是从用户文本字段输入的).我编写和创建结构没有问题; 它试图读取导致问题的值.下面我用来编写数据的代码,有人能告诉我如何读取字符串[val]和[myKey]吗？

谢谢!

#define defaultValue @"Your Name"
#define myKey @"PersonName"

- (void)textFieldAction:(id)sender {

    NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
    NSString *val;

    // Get the new value from the textfield

    val = [myTextField stringValue];

    if ([val isEqualToString:defaultValue]) {
        [defaults removeObjectForKey:myKey];
    } else {
        // [defaults setObject:val forKey:myKey];

    NSDictionary *my_dict = [NSDictionary dictionaryWithObjectsAndKeys:
                             @"Name", @"PersonName",
                             @"Email", @"PersonEmail", 
                             @"Dept", @"PersonDept", 
                             @"Job", @"PersonJob", 
                             val, myKey, 
                             @"Status", @"PersonStatus", 
                             nil];

    [defaults setObject: my_dict forKey: @"Person"];

    [[NSUserDefaults standardUserDefaults] registerDefaults:my_dict];

---

如果用户已经在plist中有信息,我想用[val]为[myKey]自动填充文本字段.这是我正在尝试使用的代码:

- (void)applicationDidFinishLaunching:(NSNotification *)notification {

    NSUserDefaults *defaults = [[NSUserDefaults standardUserDefaults] objectForKey:myKey];
    NSString *val = [defaults stringForKey:myKey];

    if (val == nil) val = defaultValue;
    [myTextField setStringValue:val];

Answer 1

您可以将值写入NSUserDefault如下:

[[NSUserDefaults standardUserDefaults] setValue:[myTextField stringValue] forKey:@"Person"];

稍后阅读如下:

[myTextField setStringValue:[[NSUserDefaults standardUserDefaults] stringForKey:@"Person"];

因此,您可以将代码简化为:

- (void)textFieldAction:(id)sender {
    [[NSUserDefaults standardUserDefaults] setValue:[myTextField stringValue] forKey:@"Person"];
    [[NSUserDefaults standardUserDefaults] synchronize];
}

您可以使用设置默认值registerDefaults:.当您只需调用以下内容即可检索该值:

- (void)applicationDidFinishLaunching:(NSNotification *)notification
{
    // ...
    [[NSUserDefaults standardUserDefaults] registerDefaults:@{@"Person", defaultValue}]
    NSString *value = [[NSUserDefaults standardUserDefaults] stringForKey:@"Person"];
    [myTextField setStringValue:value];
    // ...
}