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iosobjective-ciphoneuislideraddsubview

Continuously change value of UILabel on thumb image of UISlider

I have a UISlider(min 1 ,max 10). I want its thumb to have a UILabel placed on top of it that continuously updates and changes its text on moving the UISlider's thumb. So, I grabbed thumb image from the UISlider and added a UILabel to it but the label seems to overwrite itself without erasing the previous value once the thumb is moved.

- (IBAction)SnoozeSliderValueChanged:(id)sender {

    UIImageView *handleView = [_snoozeSlider.subviews lastObject];
    UILabel *label = [[UILabel alloc] initWithFrame:handleView.bounds];
    label.text = [NSString stringWithFormat:@"%0.0f", self.snoozeSlider.value];
    label.backgroundColor = [UIColor clearColor];
    label.textAlignment = NSTextAlignmentCenter;
    [handleView addSubview:label];

}

Initially,

enter image description here

Then, when i start dragging,

enter image description here

I want the label to erase the previous value and show current value as the thumb is moved. Any help is appreciated.Thanks!

Solution

  • Your code continuously adds new subviews. Remove the existing subviews with:

    [handleView.subviews makeObjectsPerformSelector:@(removeFromSuperview)];

    Alternatively, reuse the existing label. Perhaps using a tag and viewWithTag: to find the existing label and update (or create if not found). Reuse is more efficient than recreation.