ios - removeObjectForKey 不会从 .plist 中删除值

Question

我正在开发具有 TableView 的 iPhone 应用程序，

我想做的是点击 UITableViewCell 我想从 plist 中删除这些值，MOBILES.Brand.2 和 MOBILES.Brand.5 如果它们存在在 .plist 中，如果它们不存在于 .plist 中，那么我想将其添加到我的 .plist 中

这是我的 .plist 的结构:

:这是我的代码片段:

 - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
       plistPath = [self getPlistPath];

//PlistDict is mutableDictionary contains the keys and values of .plist (of above image) 
if ([PlistDict valueForKeyPath:@"MOBILES.Brand.2"] != nil) { //if key and it's value exists in Filter.plist

//Delete Key from .plist...
                NSMutableDictionary *savedStock = [[NSMutableDictionary alloc] initWithContentsOfFile:plistPath];
                [savedStock removeObjectForKey:@"MOBILES.Brand.2"];
                [savedStock removeObjectForKey:@"MOBILES.Brand.5"];
                [savedStock writeToFile:plistPath atomically:YES];

}else{



//Add Key to .plist
            NSMutableDictionary *data = [[NSMutableDictionary alloc] initWithContentsOfFile:plistPath];
            [data setValue:@"251" forKeyPath:@"MOBILES.Brand.2"];
            [data setValue:@"298" forKeyPath:@"MOBILES.Brand.5"];
            [data writeToFile:plistPath atomically:YES];

    }
}

-(NSString*)getPlistPath{

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

    return path;
}

在编写上面的代码片段后，它不会从 .plist 中删除键，但如果不存在，它会成功添加键。

我哪里做错了？请帮助并提前致谢。

Answer 1

问题是您正在尝试使用 NSMutableDictionary keypath 直接使用 removeObjectForKey 进行删除，这需要 exact key 而不是 keypath 并且您正在提供 keypath。使用以下取自 here 的 NSMutableDictionary 类别

@interface NSMutableDictionary (Additions)
- (void)removeObjectForKeyPath: (NSString *)keyPath;
@end

@implementation NSMutableDictionary (Additions)

- (void)removeObjectForKeyPath: (NSString *)keyPath
{
    // Separate the key path
    NSArray * keyPathElements = [keyPath componentsSeparatedByString:@"."];
    // Drop the last element and rejoin the path
    NSUInteger numElements = [keyPathElements count];
    NSString * keyPathHead = [[keyPathElements subarrayWithRange:(NSRange){0, numElements - 1}] componentsJoinedByString:@"."];
    // Get the mutable dictionary represented by the path minus that last element
    NSMutableDictionary * tailContainer = [self valueForKeyPath:keyPathHead];
    // Remove the object represented by the last element
    [tailContainer removeObjectForKey:[keyPathElements lastObject]];
}

@end

它应该适合你。

方法 - 2

如果以上方法不起作用，您可以对字典进行迭代，并专门删除键的对象。尝试

NSMutableDictionary *savedStock = [[NSMutableDictionary alloc] initWithContentsOfFile:plistPath];

NSMutableDictionary *brand=[[savedStock objectForKey:@"MOBILES"] objectForKey:@"Brand"];

[brand removeObjectForKey:@"2"];
[brand removeObjectForKey:@"5"];

干杯。