利用3个UISlider来改变一个对象的颜色

首先在 ColorView这个自定义视图的.h文件定义三个属性(作用:分别记录ColorView的red,green,blue)
@property (nonatomic,assign) CGFloat r;
@property (nonatomic,assign) CGFloat g;
@property (nonatomic,assign) CGFloat b;

#import "RootViewController.h"
 
@interface RootViewController ()
 
@end
 
@implementation RootViewController
 
- (void)viewDidLoad {
    [super viewDidLoad];   
    
    //  创建一个ColorView对象
    ColorView *colorView = [[ColorView alloc]initWithFrame:CGRectMake(50, 320, 300, 50)];
    colorView.backgroundColor = [UIColor whiteColor];
    colorView.tag = 200;
    [self.view addSubview:colorView];
    [colorView release];
    
//  创建三个UISlider来控制来控制ColorView对象的颜色
    //  创建第一个UISlider对象
    UISlider *slider1 = [[UISlider alloc]initWithFrame:CGRectMake(50, 380, 300, 30)];
    slider1.minimumValue = 0;
    slider1.maximumValue = 256;
    slider1.value = 128;
    slider1.minimumTrackTintColor = [UIColor redColor];
    slider1.maximumTrackTintColor = [UIColor grayColor];
    slider1.thumbTintColor = [UIColor greenColor];
    [slider1 addTarget:self action:@selector(redColor:) forControlEvents:(UIControlEventValueChanged)];
    [self.view addSubview:slider1];
    [slider1 release];
    
    //  创建第二个UISlider对象
    UISlider *slider2 = [[UISlider alloc]initWithFrame:CGRectMake(50, 440, 300, 30)];
    slider2.minimumValue = 0;
    slider2.maximumValue = 256;
    slider2.value = 128;
    slider2.minimumTrackTintColor = [UIColor blueColor];
    slider2.maximumTrackTintColor = [UIColor grayColor];
    slider2.thumbTintColor = [UIColor greenColor];
    [slider2 addTarget:self action:@selector(blueColor:) forControlEvents:(UIControlEventValueChanged)];
    [self.view addSubview:slider2];
    [slider2 release];
    
    //  创建第三个UISlider对象
    UISlider *slider3 = [[UISlider alloc]initWithFrame:CGRectMake(50, 500, 300, 30)];
    slider3.minimumValue = 0;
    slider3.maximumValue = 256;
    slider3.value = 128;
    slider3.minimumTrackTintColor = [UIColor greenColor];
    slider3.maximumTrackTintColor = [UIColor grayColor];
    slider3.thumbTintColor = [UIColor greenColor];
    [slider3 addTarget:self action:@selector(greenColor:) forControlEvents:(UIControlEventValueChanged)];
    [self.view addSubview:slider3];
    [slider3 release];
    
}
- (void)blueColor:(UISlider *)slider
{
    ColorView *blueColor = (ColorView *)[self.view viewWithTag:200];
    blueColor.b = slider.value;
    blueColor.backgroundColor = [UIColor colorWithRed:blueColor.r/255.0 green:blueColor.g/255.0 blue:blueColor.b/255.0 alpha:1];
}
 
- (void)greenColor:(UISlider *)slider
{
    ColorView *greenColor = (ColorView *)[self.view viewWithTag:200];
    greenColor.g = slider.value;
    greenColor.backgroundColor = [UIColor colorWithRed:greenColor.r/255.0 green:greenColor.g/255.0 blue:greenColor.b/255.0 alpha:1];
}
 
- (void)redColor:(UISlider *)slider
{
    ColorView *redColor = (ColorView *)[self.view viewWithTag:200];
    redColor.r = slider.value;
    redColor.backgroundColor = [UIColor colorWithRed:redColor.r/255.0 green:redColor.g/255.0 blue:redColor.b/255.0 alpha:1];
}
 
 
- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}