Question

我是iOS开发的新手我遇到了一个标签不想在NSArray中显示值的问题。请有人帮忙指出哪里出错了，为什么？

// given rows and cols as the number of rows and columns of the matrices

size_t max_index = rows * cols - 1;

for ( size_t i = 0, j = 0; i <= max_index; ++i ) {
    c_rm[i] = a_rm[i] + b_cm[j];
    j += rows;
    if ( j > max_index )
        j -= max_index;
}

运行代码时得到的结果：NSLog打印正确的值，但setText方法打印“（”到标签。

这是代码，因为我没有放入URL，运行代码时没有错误。

projectArray在.h文件中定义为：@property（nonatomic，copy）NSArray * projectArray;

这是在NSLog中打印的内容：

NSDictionary *json = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&error];

    json_data = [json objectForKey:@"data"];

    content = [json_data objectForKey:@"content"];

    NSMutableArray *contentTemp = [[NSMutableArray alloc] initWithCapacity:content.count];

    for (NSDictionary *contentInfo in content) {

        project_details *mvm = [[project_details alloc] init];
        mvm.bname = contentInfo[@"bname"];
        mvm.burl = contentInfo[@"burl"];
        mvm.p_num = contentInfo[@"p_id"];
        mvm.pname = contentInfo[@"pname"];
        mvm.pdesc = contentInfo[@"pdesc"];
        mvm.purl = contentInfo[@"purl"];
        mvm.plive = contentInfo[@"plive"];
        mvm.pcompleted = contentInfo[@"pcompleted"];
        mvm.days = contentInfo[@"days"];
        mvm.pfunds = contentInfo[@"pfunds"];
        mvm.amount = contentInfo[@"amount"];
        mvm.perc = contentInfo[@"perc"];

        [contentTemp addObject:mvm];

    }

    self.projectArray = contentTemp;

    dispatch_async(dispatch_get_main_queue(), ^{
         [self.label setText:[NSString stringWithFormat:@"%@", [self.projectArray valueForKey:@"bname"]]];

          NSLog(@"%@", [self.projectArray valueForKey:@"bname"]);
    });


}];

[dataTaskProject resume];

Answer 1

在NSArray上调用valueForKey会返回NSArray。你可能想要的是[(mvm *)self.projectArray.firstObject bname]。您的self.projectArray包含一个或多个mvm个对象，这些对象具有bname属性。

您可以将.firstObject更改为数组索引（即[1]，[2]等），具体取决于您要在阵列中访问的内容（它不清楚）来自你的代码给我。

标签的setText - Objective C Xcode 7

1 个答案: