UISlider值

Question

我正在尝试创建一个应用程序，它有三个UISlider用于选择R，G和B值。滑块应根据滑块值更改标签的颜色。

ViewController.h

#import <UIKit/UIKit.h>

 @interface ViewController : UIViewController
{
NSInteger color;

IBOutlet UISlider *redSlider;
IBOutlet UISlider *greenSlider;
IBOutlet UISlider *blueSlider;
IBOutlet UILabel  *colorLabel;
}

@property (nonatomic, retain) UISlider *redSlider;
@property (nonatomic, retain) UISlider *greenSlider;
@property (nonatomic, retain) UISlider *blueSlider;

colorLabel.textColor = [UIColor colorWithRed: redSlider.value green:greenSlider.value
blue:blueSlider.value alpha:1];


 @end

ViewController.m

 #import "ViewController.h"

 @interface ViewController ()


 @end

 @implementation ViewController

 - (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
}

- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}

@synthesize redSlider, greenSlider, blueSlider;




@end

这就是我到目前为止所拥有的，我完全被卡住了。

Answer 1

你可以这样做...

ViewController.h

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController

@end

ViewController.m

#import "ViewController.h"

@interface ViewController ()

// you need to make sure these are actually created
// and give them all a target of self and action sliderValueChanged
@property (nonatomic, retain) UISlider *redSlider;
@property (nonatomic, retain) UISlider *greenSlider;
@property (nonatomic, retain) UISlider *blueSlider;

// not sure where this is set up
@property (nonatomic, strong) UILabel *colorLabel;

@end

@implementation ViewController

 - (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.

    // You may have to create your labels and sliders in here...
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

- (void)sliderValueChanged
{
    // the sliders have changed so set the colour of the label
    // based on the new values of the sliders.
    self.colorLabel.textColor = [UIColor colorWithRed:self.redSlider.value
                                                green:self.greenSlider.value
                                                 blue:self.blueSlider.value
                                                alpha:1.0];
}

@end

Answer 2

因为你实际上没有问题，所以我要猜测你的代码没有编译，因为它不会编译。

colorLabel.textColor = [UIColor colorWithRed: redSlider.value green:greenSlider.value blue:blueSlider.value alpha:1];

上面的行不属于你的界面。我建议您将当前拥有的代码更改为如下所示。

ViewController.h

@interface ViewController : UIViewController

// You don't need the ivars anymore these get generated with the properties below  

@property (nonatomic, retain) IBOutlet UISlider *redSlider;
@property (nonatomic, retain) IBOutlet UISlider *greenSlider;
@property (nonatomic, retain) IBOutlet UISlider *blueSlider;
@property (nonatomic, retain) IBOutlet UILabel *colorLabel
@property (assign) NSInteger color;

@end

ViewController.m

@implementation ViewController

// Also no need for the synthesize as these also get generated automatically

- (void)viewDidLoad
{
    [super viewDidLoad];
    // To change the actual color when changing the value of a slider move this to a method that gets called on slider changed.
    colorLabel.textColor = [UIColor colorWithRed:self.redSlider.value green:self.greenSlider.value self.blue:blueSlider.value alpha:1];
}

@end

一旦你真的问了一个问题，我也许也能帮到你。

Answer 3

你的ViewController.h :-

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController
{    
IBOutlet UISlider *redSlider;
IBOutlet UISlider *greenSlider;
IBOutlet UISlider *blueSlider;
IBOutlet UILabel  *colorLabel;
}

@property (nonatomic, retain) UISlider *redSlider;
@property (nonatomic, retain) UISlider *greenSlider;
@property (nonatomic, retain) UISlider *blueSlider;

 @end

您的ViewController.m将如下所示：-

#import ViewController.h

@interface ViewController ()
 @end

@implementation ViewController
@synthesize redSlider, greenSlider, blueSlider;
 - (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
[self changeLabelColor];
}

- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}

-(Void) changeLabelColor
    {
colorLabel.backgroundcolor = [UIColor colorWithRed:redSlider.value green:redSlider.value blue:redSlider.value alpha:1.0];
     }
        @end

因为我没有复制粘贴，而且我已经写好了，所以可能有一些打字错误。textcolor不会改变标签的颜色，所以我把它改成了backgroundcolor。您还可以使用IBAction添加滑块方法。