无法读取UIStepper的值

Question

我在试着设计我自己的间歇训练计时器。现在，我在读取UIStepper控件的值时遇到了问题。

我在UIStepper控制器上设置了一个int，这个控制器到目前为止还能工作。

- (IBAction)stepperChange:(id)sender {

// converting double to int
int temp = [[NSNumber numberWithDouble:[(UIStepper *)sender value]] intValue];

NSLog(@"stepper was pressed. Current values is %d", [[NSNumber numberWithDouble:[(UIStepper *)sender value]] intValue]);

self.intervalSeconds.text = [NSString stringWithFormat:@"%i", [[NSNumber numberWithDouble:[(UIStepper *)sender value]] intValue]];

mainInt = [[NSNumber numberWithDouble:[(UIStepper *)sender value]] intValue];

}

到目前一切尚好。问题是，当计时器达到0时，我希望将计时器重置为UISteppers值。但是，当我试图直接读取不带(Id)发送者的分步器值时，我总是得到0的值。

e.g

-(void)readStepperValue {

NSLog(@"Read UIStepper control value: %f", [intervalStepper value]);

}

我想这只是一个愚蠢的初学者错误..。

好的，我刚刚做了一个超级简单的测试应用程序，代码看起来如下：

vierController.h：

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController {

IBOutlet UIStepper *stepper;
IBOutlet UILabel *stepperValue;
}

@property (nonatomic, strong) UIStepper *stepper;
@property (nonatomic, strong) UILabel *stepperValue;

- (IBAction)showStepperValue;

@end

viewController.m：

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController
@synthesize stepper, stepperValue;

- (IBAction)showStepperValue {
int temp = stepper.value;
stepperValue.text = [NSString stringWithFormat:@"%i", temp];
[self showValue];
}


- (void)showValue {
int temp = stepper.value;
NSLog(@"stepper.value: %i", temp);
}


- (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.
}

@end

标签在IBAction方法中被正确更新。但是当我调用一个独立的方法(showValue)时，它不能读取控制器的值，它不在IBAction内.

Answer 1

换个办法试试。

viewController.h：

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController

@property (nonatomic, strong) IBOutlet UIStepper *stepper;
@property (nonatomic, strong) IBOutlet UILabel *stepperValue;

- (IBAction)showStepperValue;

@end

viewController.m：

#import "ViewController.h"

@implementation ViewController

- (IBAction)showStepperValue {
    double temp = self.stepper.value;
    self.stepperValue.text = [NSString stringWithFormat:@"%f", temp];
    [self showValue];
}

- (void)showValue {
    double temp = self.stepper.value;
    NSLog(@"self.stepper.value: %f", temp);
}

@end

摆脱iVars，只依赖属性不仅减少了您需要编写的代码量，而且还有助于消除任何iVar/属性绑定错误。

更新: self.stepper.value是双重的，而不是int (但这不是您的问题)。