iOS: how to set custom background colour with sliders?

Question

First off I want to say I saw a couple of posts on this site about how to do this, although none seemed to work for me so please don\'t close this down until I get it working.

Answer 1

In your ViewController.h file define

@property (nonatomic, strong) IBOutlet UISlider *mySlider;

In ViewController.m file, add this:

- (void) sliderValueChanged:(UISlider *)slider
{
    // Handle your color changing logic here
    myView.backgroundColor = [UIColor colorWithRed:0.4f green:0.5f blue:1.0f alpha:1.0f];
}

In Interface Builder, Drag UISlider to view and set its "Value Changed" event outlet to sliderValueChanged method.

Now as you change the slider on screen, the color should changed based on your logic in the method sliderValueChanged

Below is the logic as per your requirement:

- (void) sliderValueChanged:(UISlider *)slider
{
    // Assuming slider minimum is 0 and maximum is 1
    CGFloat redVal = 0.0f;
    CGFloat yellowVal = 0.0f;
    CGFloat blueVal = 0.0f;
    if (slider == redSlider)
    {
        redVal = slider.value;
    }
    else if (slider == yellowSlider)
    {
        yellowVal = slider.value;
    }
    else if (slider == blueSlider)
    {
        blueVal = slider.value;
    }
    myView.backgroundColor = [UIColor colorWithRed:redVal green:greenVal blue:blueVal alpha:1.0f];
}