iOS plist文件写入和读取

有小伙伴问了一个问题，plist写入失败的问题。下面我说下相关的代码：

1.写入plist（代码创建的plist文件）此方法是不断写入，不会替换之前数据

- (void)insertToPlist:(NSDictionary *)dictionary nickName:(NSString
*)nickName {

    NSString *plistPath = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,
NSUserDomainMask,
YES) firstObject]
stringByAppendingPathComponent:@"chatRoom.plist"];

    

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

    //下边if判断很重要，不然会写入失败.

    if (!userDict) {

        userDict = [[NSMutableDictionary
alloc] init];

    }

    //设置属性值

    [userDict setObject:dictionary
forKey:nickName];

    //写入文件

    [userDict writeToFile:plistPath
atomically:YES];

}

注意：如果想每次都替换数据，把上边的[[NSMutableDictionary alloc] initWithContentsOfFile:plistPath]改成：[[NSMutableDictionary alloc] init]，if语句三行代码去掉即可

2.读取plist（代码创建的plist文件）

- (void)getPlistDictionary:(NSString *)nickName

{

    NSString *plistPath = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,
NSUserDomainMask,
YES) firstObject]
stringByAppendingPathComponent:@"chatRoom.plist"];

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

   
//userDict[nickName]就是上边方法存入的字典,取出来就可以进行相应的赋值操作啦

}