Question

使用代码以百分比显示下载进度

float progress = [[NSNumber numberWithInteger:totalBytesWritten] floatValue];
        float total = [[NSNumber numberWithInteger: totalBytesExpectedToWrite] floatValue];

        NSString *percentage = [NSString stringWithFormat:@"%d%%", (int)((progress/total)*100)];
        [_label setText:[NSString stringWithFormat:@"%@%%", percentage]];
 _label = [[UILabel alloc]initWithFrame:CGRectMake(323.43, 148.84, 42, 19)];
        [_label setText: percentage];
        _label.numberOfLines = 1;
        _label.baselineAdjustment = UIBaselineAdjustmentAlignBaselines;
        _label.adjustsFontSizeToFitWidth = YES;
        _label.minimumScaleFactor = 10.0f/12.0f;
        _label.clipsToBounds = YES;
        _label.backgroundColor = [UIColor blackColor];
        _label.textColor = [UIColor whiteColor];
        _label.textAlignment = NSTextAlignmentCenter;
        [self.view addSubview:_label];

如果我使用_label.backgroundColor = [UIColor blackColor];进度标签正常工作。但是，如果我使用_label.backgroundColor = [UIColor clearColor];个数字叠加在一起

为什么？

_label.backgroundColor = [UIColor blackColor];

_label.backgroundColor = [UIColor clearColor];

Answer 1

您似乎正在添加多个标签[self.view addSubview: _label]。此代码只应执行一次。在黑色背景下，您只能看到最顶部的标签。背景清晰，你可以看到所有

Answer 2

您正在使用方法[self.view addSubview: _label]添加多个标签如果您希望在调试时更直观地使用Debug View Hierarchy。要解决此问题，您可以检查_label是否为nil，并且只设置文本。请参阅以下代码：

    float progress = [[NSNumber numberWithInteger:totalBytesWritten] floatValue];
    float total = [[NSNumber numberWithInteger:totalBytesExpectedToWrite] floatValue];

    NSString *percentage = [NSString stringWithFormat:@"%.f%%", ((progress / total) * 100)];

    if (!_label) {

        _label = [[UILabel alloc] initWithFrame:CGRectMake(323.43, 148.84, 42, 19)];

        _label.numberOfLines = 1;
        _label.baselineAdjustment = UIBaselineAdjustmentAlignBaselines;
        _label.adjustsFontSizeToFitWidth = YES;
        _label.minimumScaleFactor = 10.0f/12.0f;
        _labellabel.clipsToBounds = YES;
        _label.backgroundColor = [UIColor blackColor];
        _label.textColor = [UIColor whiteColor];
        _label.textAlignment = NSTextAlignmentCenter;

        [self.view addSubview:_label];
   }

   _label.text = percentage;

请注意，您正在尝试在初始化文本之前设置文本：[_label setText:[NSString stringWithFormat:@"%@%%", percentage]];如果_label为nil，则应用程序崩溃。尽量避免手动设置框架而不是使用自动布局。

Answer 3

我认为，标签已经重叠了。所以你可以使用＆＃34; tag＆＃34;每次都删除标签并重新创建它的值。

添加标记

_label = [[UILabel alloc] initWithFrame:CGRectMake(323.43, 148.84, 42, 19)];  // after you will set the tag for the required Label.
_label.tag = 505;

删除并重新创建标签

[[self.view viewWithTag:505]removeFromSuperView]; // after you will create the Label
_label = [[UILabel alloc] initWithFrame:CGRectMake(323.43, 148.84, 42, 19)];

标签的进展

3 个答案: