可以在UISlider的拇指图像上添加标签吗？ [英] Is that possible to add a label to the UISlider's thumb image?

问题描述

我想在滑块的拇指上添加一个标签，该标签应该显示滑块的值，并且当拇指向右侧拖动时也会改变。
是否有可能??

I want to add a label to the slider's thumb which should show the value of the slider and changes too when thumbs is being dragged towards right side. Is it possible??

任何意见或建议都将受到赞赏。

Any comments or suggestion would be appreciated.

推荐答案

您可以执行与此示例类似的操作，直接将文本绘制到您的拇指图像。这是一个粗略的例子，所以你需要改变它才能对你的项目有意义。

You could do something similar to this example which draws text directly to your thumb image. It's a rough example so you will need to change it to make sense for your project.

- (IBAction)sliderValueChanged:(id)sender {
    UISlider *aSlider = (UISlider *)sender;
    NSString *strForThumbImage = 
     [NSString stringWithFormat:@"%.0f", aSlider.value * 100]
    UIImage *thumbImage = [self addText:self.thumbImage 
                                   text:strForThumbImage];
    [aSlider setThumbImage:thumbImage forState:aSlider.state];
}

//Add text to UIImage 
-(UIImage *)addText:(UIImage *)img text:(NSString *)text1{ 
    int w = img.size.width; 
    int h = img.size.height; 
    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB(); 
    CGContextRef context = CGBitmapContextCreate( NULL, 
                                                  w, 
                                                  h, 
                                                  8, 
                                                  4 * w, 
                                                  colorSpace, 
                                                  kCGImageAlphaPremultipliedFirst); 
    CGContextDrawImage(context, CGRectMake(0, 0, w, h), img.CGImage); 

    char* text= (char *)[text1 cStringUsingEncoding:NSASCIIStringEncoding]; 
    CGContextSelectFont(context, "Arial",12, kCGEncodingMacRoman); 
    CGContextSetTextDrawingMode(context, kCGTextFill); 
    CGContextSetRGBFillColor(context, 0, 0, 0, 1); 
    CGContextShowTextAtPoint(context,3,8,text, strlen(text)); 
    CGImageRef imgCombined = CGBitmapContextCreateImage(context); 

    CGContextRelease(context); 
    CGColorSpaceRelease(colorSpace); 

    UIImage *retImage = [UIImage imageWithCGImage:imgCombined]; 
    CGImageRelease(imgCombined); 

    return retImage; 
}

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