Objective-C：自动更新标签文本

发布于 2024-12-07 21:51:38 字数 650 浏览 7 评论 0 原文

我是 Objective-C 的新手，我需要你的帮助！在下面您将看到的代码中，我的标签从选取器视图中选取数据。我希望不使用“计算”IBAction，而是在用户更改选择器视图中的值时实时更新我的“chargeLabel.text”。

-(IBAction)calculate:(id)sender {
float floatTime;
if ([typeLabel.text isEqualToString:@"NiMH"])
{
    floatTime=([mAhLabel.text floatValue]/chargerSlider.value)*1.5;
} else {
    floatTime=([mAhLabel.text floatValue]/chargerSlider.value)*1.4;
}
int intHourhs=(floatTime);
float floatHours=(intHourhs);
float floatMinutes=(floatTime-floatHours)*60;
NSString *stringTotal = [NSString stringWithFormat: @"Hours: %.0i Minutes: %.0f", intHourhs, floatMinutes];
chargeLabel.text=stringTotal;

}

原文

I am new to Objective-C and i need your help! In the code that you will see below, my labels pick data from a picker view. I would like instead of using a "calculate" IBAction, to have my "chargeLabel.text" updated in real time as soon as the user changes a value in the picker view.

-(IBAction)calculate:(id)sender {
float floatTime;
if ([typeLabel.text isEqualToString:@"NiMH"])
{
    floatTime=([mAhLabel.text floatValue]/chargerSlider.value)*1.5;
} else {
    floatTime=([mAhLabel.text floatValue]/chargerSlider.value)*1.4;
}
int intHourhs=(floatTime);
float floatHours=(intHourhs);
float floatMinutes=(floatTime-floatHours)*60;
NSString *stringTotal = [NSString stringWithFormat: @"Hours: %.0i Minutes: %.0f", intHourhs, floatMinutes];
chargeLabel.text=stringTotal;

}

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虚拟世界 2024-12-14 21:51:38

您必须实现 UIPickerViewDelegate 协议。
然后，在 didSelectRow 方法中执行您想要的操作

- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
{
    ...
    //here your code

}

检查 UIPickerViewDelegate 协议参考

编辑： 我刚刚意识到您的访问chargerSlider 的 value 属性，如果它是 UISlider，则不需要实现任何委托，只需将 IBAction 分配给 Value更改了 IB 中滑块的选择器。

You have to implement UIPickerViewDelegate Protocol.
Then, perform whatever you want in didSelectRow method

- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
{
    ...
    //here your code

}

Check UIPickerViewDelegate Protocol Reference

EDIT: I just realized that your accessing value property of chargerSlider if it is a UISlider you don't need to implement any delegate, just assing your IBAction to the Value Changed selector of the slider in IB.