将 int 与文本字段中的数据输入相乘得到标签

Question

int Bonus = .3（需要百分比，这等于 30%）

label = (textfield * Bonus)

Objective-C 新手，如果需要更多说明，请随时待命。

更新：已解决！解决方案：

这里是 .h 文件：

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController {

 IBOutlet UILabel *label;
 IBOutlet UITextField *textfield;
}


- (IBAction)save:(id)sender;

@end

这是.m文件

#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.
}

- (IBAction)save:(id) sender {

    float x = ([textfield.text floatValue]);
    float bonus = .3;
    float result;
    result = x * bonus / 10; 

// Divide by 10 to keep it percentage based




    label.text = [[NSString alloc] initWithFormat:@"%.2f", result];

感谢大家的帮助！尤其是许音！！

Answer 1

我同意pacman321，也许下次尝试添加更多信息..

看起来你的问题是：

//1.> "convert NSString to number" 
float value = [textfield.text floatValue];

//2.> do the math 
value = value * Bonus; //Could also be value *= Bonus;

//3.> Convert number back to NSString
label.text = [NSString stringWithFormat:@"%f", value];

我认为这就是你所需要的，但这里有一些建议：确保你的文本字段只有数值。并且可能需要注意要在标签中显示多少位数。

Answer 2

这里都解释过了https://developer.apple.com/library/ios/documentation/Cocoa/Conceptual/Strings/Articles/FormatStrings.html

textfield.text = [NSString stringWithFormat:@"%d%%", Bonus * 100]