Ashutosh Ashutosh - 6 months ago 23
iOS Question

Is that possible to add a label to the UISlider's thumb image?

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??
Anu comments or suggestion would be appreciated.

Thanks,

Answer

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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