如何在 iOS 中以编程方式更新标签？

Question

我在更新标签时遇到问题。它不会删除旧名称，因此新名称位于旧名称之上。任何帮助将不胜感激..

    NSDictionary *arrDictionary = [NSJSONSerialization JSONObjectWithData:requestHandler options:0 error:nil];

    NSDictionary *vendorDic = [arrDictionary objectForKey:@"feed"];
    NSLog(@" the response is %@",vendorDic);
     NSArray * titleArray  = [vendorDic valueForKey:@"title"];
    NSArray * reviewArray = [vendorDic valueForKey:@"review"];
    if (titleArray.count == 0) {
         self.scrollViewReview.contentSize = CGSizeMake(0*172, _scrollViewReview.frame.size.height);
    }
    else{
        NSUInteger x =[titleArray count];

        self.scrollViewReview.contentSize = CGSizeMake(x*172, _scrollViewReview.frame.size.height);
    for(int i = 0;i <= titleArray.count-1;i = i + 1){
        _noReview.hidden = YES;
        UILabel * titleLabel =  [[UILabel alloc] initWithFrame: CGRectMake(i*172, 0, 100, 50)];
        UILabel * reviewLabel = [[UILabel alloc] initWithFrame:CGRectMake(i * 172 , 30, 200, 50)];
        titleLabel.clearsContextBeforeDrawing =YES;
        titleLabel.clipsToBounds = YES;
        reviewLabel.clipsToBounds = YES;
        reviewLabel.clearsContextBeforeDrawing=YES;
        NSString* titleStr = [NSString stringWithFormat:@"%@", titleArray[i]];
        NSString * reviewStr =[NSString stringWithFormat:@"%@",reviewArray[i]];
       // NSLog(@" loop in for  title: %@",titleStr);
       //NSLog(@" loop in for  title: %@",reviewStr);
        titleLabel.text = titleStr;
        titleLabel.textColor = [UIColor greenColor];
        titleLabel.font =[UIFont fontWithName:@"Arial-BoldMT" size:16.0];
        reviewLabel.font = [UIFont systemFontOfSize:12];
        reviewLabel.text = reviewStr;//etc...
        [self.viewReview addSubview:titleLabel];
        [self.viewReview addSubview:reviewLabel];

    }
    }

Labels are doesn't remove the old names so new names go on top of old ones like this...

Note : titleLabel is "Nice Product" And reviewLabel is "This is Amazing"

Answer 1

每次循环时都在重新创建标签。

您应该在 UILabel 数组中创建它们一次，然后 re-use 它们 - 如果您需要添加新的，请扩展数组。

Answer 2

在添加新的子视图之前删除所有子视图，如下所示

    NSArray *viewsToRemove = [self.view subviews];
for (UIView *v in viewsToRemove) {
    [v removeFromSuperview];
}

上面的代码应该在下面这一行之前添加，

[self.viewReview addSubview:titleLabel];
[self.viewReview addSubview:reviewLabel];

Answer 3

我不知道为什么你每次都创建新的 UILabel 如果你不想保留旧的 UILabel 文本。
假设你有 IBOutlet titleLabel，那么你不需要每次都创建新的 UILabel。您可以只更改视图中现有 UILabel 的文本：例如

[self.titleLabel setText:titleStr];

它还 reduces/saves 一次又一次地设置 UILabel 的各种属性。只需要在 Interface Builder 中设置 UILabel 的相关属性即可。
注意：如果你想保留旧的 UILabel 那么你需要完全不同的逻辑。

假设您想每次显示不同数量的评论。在这种情况下，您可以通过以下代码删除 self.viewReview 的所有 subviews：

    for (UIView * subUIView in self.viewReview.subviews)
    {
        [subUIView removeFromSuperview];
    }

Answer 4

请在您的回答中更改 NSLog 后的以下行。 titleLabel.text=@""; titleLabel.text = titleStr; titleLabel.text颜色 = [UIColor 绿色]; titleLabel.font =[UIFont fontWithName:@"Arial-BoldMT" size:16.0]; reviewLabel.font = [UIFont systemFontOfSize:12]; reviewLabel.text =@""; reviewLabel.text =reviewStr;

Answer 5

好的 - 首先为您的标题创建数组作为视图控制器的成员

NSMutableArray *titleLabels     = [NSMutableArray array];
NSMutableArray *reviewLabels    = [NSMutableArray array];

然后更新您的函数，使其看起来更像这样

for(int i = 0;i <= titleArray.count-1;i = i + 1){
    _noReview.hidden = YES;

    UILabel * titleLabel;
    UILabel * reviewLabel;
    if (i >= [titleLabels count]) {
        titleLabel =  [[UILabel alloc] initWithFrame: CGRectMake(i*172, 0, 100, 50)];
        reviewLabel = [[UILabel alloc] initWithFrame:CGRectMake(i * 172 , 30, 200, 50)];

        [titleLabels addObject:titleLabel];
        [reviewLabels addObject:reviewLabel];
    }
    else {
        titleLabel = [titleLabels objectAtIndex:i];
        reviewLabels = [reviewLabels objectAtIndex:i];
    }

    // do your other stuff here

每次调用函数时，如果返回的标题多于标签，它将创建新实例，并将它们添加到数组中。当您遍历数组时，它将 re-use 个实例。

如何在 iOS 中以编程方式更新标签？

How to update Label Programmatically in iOS?

iphone

objective-c

uilabel

ios