出现错误时，尽量写值plist中

Question

我想写价值的plist，但有错误

代码：

NSString *path = [[NSBundle mainBundle] pathForResource:@"Properties" ofType:@"plist"]; 
    NSDictionary *dict = [[NSDictionary alloc] initWithContentsOfFile:path]; 
    [dict setObject:[NSNumber numberWithInt:Quant] forKey:@"Quant"]; 
    [dict writeToFile:path atomically:YES]; 

错误：

No visible @interface for 'NSDictionary' declares the selector 'setObject:forKey:' 

Answer 1

你不能修改不可变的NSDictionary。你必须使用一个可变的副本：

NSMutableDictionary *dict = [[[NSDictionary alloc] initWithContentsOfFile:path] mutableCopy];