iOS-UI-创建3个UISlider-分别设置划过区域的颜⾊分别为红,黄,蓝-通过控制三个slider改变self.view的背景颜⾊

#import "ViewController.h"

@interface ViewController ()
@property (nonatomic, retain) UISlider *red;
@property (nonatomic, retain) UISlider *green;
@property (nonatomic, retain) UISlider *blue;
@property (nonatomic, retain) UISlider *alpul;
@end

@implementation ViewController

• (void)viewDidLoad {
  [super viewDidLoad];
  // Do any additional setup after loading the view, typically from a nib.
  self.view.backgroundColor = [UIColor whiteColor];

  /*创建3个UISlider 要求 :
  1.居中显⽰
  2.分别设置划过区域的颜⾊分别为红,黄,蓝
  3.通过控制三个slider改变self.view的背景颜⾊。
  4.添加第四个UISlider,改变透明度
  */

  [self rede];
  [self gree];
  [self bluee];
  [self alpu];
  }

• (void)rede
  {
  self.red = [[UISlider alloc] initWithFrame:CGRectMake(self.view.center.x / 2, 100, 200, 20 )];
  _red.minimumValue = 0;
  _red.maximumValue = 256;
  [_red addTarget:self action:@selector(Action:) forControlEvents:UIControlEventValueChanged];
  [self.view addSubview:_red];
  [_red release];

}

• (void)gree
  {
  self.green = [[UISlider alloc] initWithFrame:CGRectMake(self.view.center.x / 2, 150, 200, 20 )];
  _green.minimumValue = 0;
  _green.maximumValue = 256;
  [_green addTarget:self action:@selector(Action:) forControlEvents:UIControlEventValueChanged];
  [self.view addSubview:_green];
  [_green release];

}

• (void)bluee
  {
  self.blue = [[UISlider alloc] initWithFrame:CGRectMake(self.view.center.x / 2, 200, 200, 20 )];
  _blue.minimumValue = 0;
  _blue.maximumValue = 256;
  [_blue addTarget:self action:@selector(Action:) forControlEvents:UIControlEventValueChanged];
  [self.view addSubview:_blue];
  [_blue release];

}

• (void)alpu
  {
  self.alpul = [[UISlider alloc] initWithFrame:CGRectMake(self.view.center.x / 2, 250,200, 20 )];
  _alpul.minimumValue = 0;
  _alpul.maximumValue = 1;
  [_alpul addTarget:self action:@selector(Action:) forControlEvents:UIControlEventValueChanged];
  [self.view addSubview:_alpul];
  [_alpul release];
  }
• (void)Action:(UISlider *)sender
  {
  self.view.backgroundColor = [UIColor colorWithRed:self.red.value / 255.0 green:self.green.value/ 255.0 blue:self.blue.value / 255.0 alpha:1];
  }