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标题: iphone - 写入 plist 字典中的字符串 [打印本页]

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作者: 菜鸟教程小白    时间: 2022-12-12 22:28
标题: iphone - 写入 plist 字典中的字符串

我使用的 plist 结构如下:plist, array, dict key string key string/dict, dict key string key string/dict,/array,/plist.

我想要使用以下代码将当前字典中的“完成”字符串的值设置为"is"。

但是现在，代码用当前字典的字符串替换了整个字典数组(不过，“完成”键的值应该是"is"。)

什么是我想要的正确代码？

在 DetailViewController.m 中:

-(IBAction)favoriteButtonPressedid)sender
{

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *path = [documentsDirectory stringByAppendingPathComponent"Object.plist"];


[[detailsDataSource objectAtIndex: detailIndex] setValue"Yes" forKey"Done"];
[[detailsDataSource objectAtIndex: detailIndex] writeToFile:path atomically:YES];
}

detailsDataSource 和 detailIndex 是从 TableViewController.m segue 收到的。

TableViewController.m segue 部分:

    detailViewController.detailsDataSource = [[NSArray alloc]initWithArraybjectsArray];
    detailViewController.detailIndex = selectedRowIndex.row;

DetailViewController viewDidLoad

if ([[[detailsDataSource objectAtIndex: detailIndex] valueForKey"Favorite"] isEqual"Yes"])  {

    [favoriteButton setImage:[UIImage imageNamed"favoritedItem.png"] forState:UIControlStateSelected | UIControlStateHighlighted];
 }


districtLabel.text = [[detailsDataSource objectAtIndex: detailIndex] valueForKey"District"];

detailsDataSource 数组在 detailViewController 中像这样使用，所以我不能从数组更改为字典，在这种情况下必须制作一个可变副本。

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Best Answer-推荐答案

setValue:forKey 不用于修改可变字典。您应该使用 setObject:forKey。即，这个:

[[detailsDataSource objectAtIndex: detailIndex] setValue"Yes" forKey"Done"];

应该是:

[[detailsDataSource objectAtIndex: detailIndex] setObject"Yes" forKey:@"Done"];

如果这不能解决问题，请确保字典和数组都是可变的:

-(IBAction)favoriteButtonPressedid)sender {

    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    NSString *path = [documentsDirectory stringByAppendingPathComponent:@"Object.plist"];

    NSMutableDictionary *mutDict = [NSMutableDictionary dictionaryWithDictionary:[detailsDataSource objectAtIndex:detailIndex]];
    [mutDict setObject:@"Yes" forKey:@"Done"];

    NSMutableArray *tmpMutArr = [NSMutableArray arrayWithArray:detailsDataSource];
    [tmpMutArr replaceObjectAtIndex:detailIndex withObject:[NSDictionary dictionaryWithDictionary:mutDict]];  // make dict immutable before replacing.  Casting it ( (NSDictionary *)mutDict ) works too.

    [detailsDataSource release], detailsDataSource = nil;
    detailsDataSource = [[NSArray alloc] initWithArray:tmpMutArr];

    [detailsDataSource writeToFile:path atomically:YES];
}

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另外，您可以使用 [NSNumber numberWithBool:YES] 代替 @"Yes":
[mutDict setObject:[NSNumber numberWithBool:YES] forKey:@"Done"];
通常会比使用 @"Yes" 更好。

还有:

districtLabel.text = [[detailsDataSource objectAtIndex: detailIndex] valueForKey:@"Yes"];

应该是:

districtLabel.text = [[detailsDataSource objectAtIndex: detailIndex] objectForKey:@"Yes"];

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还注意到您可能存在内存泄漏:

detailViewController.detailsDataSource = [[NSArray alloc] initWithArraybjectsArray];

确保在使用保留的属性 setter 时自动释放。

关于iphone - 写入 plist 字典中的字符串，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/11923593/

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