Question

我是iPhone App开发的新手，下面是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.

    [self updateMyView];

}

- (IBAction)clickButtonResult:(id)sender
{
    enteredText = [textField text]; // Or textField.text

    NSLog(@"Number 1 : %i", number_1);
    NSLog(@"Number 2 : %i", number_2);
    NSLog(@"Entered Text is %@", enteredText);

    int NUM_RESULT = number_1 + number_2;
    verify_result = [NSString stringWithFormat:@"%i", NUM_RESULT];

    NSLog(@"Verify Result : %@", verify_result);
    NSString *final_result = [NSString stringWithFormat:@"%d", [enteredText isEqualToString:verify_result]];
    int final_int_result = [final_result integerValue];


    if (final_int_result) {
        //result_label.text = @"Correct";
        NSLog(@"Correct");
        [self updateMyView];
    } else {
        //result_label.text = @"Wrong";
        NSLog(@"Wrong");
    }
}

- (int)getRandomNumberBetween:(int)min maxNumber:(int)max
{
    return min + arc4random() % (max - min + 1);
}

- (void) updateMyView
{
    number_1 = [self getRandomNumberBetween:10 maxNumber:99];
    number_2 = [self getRandomNumberBetween:10 maxNumber:99];

    num_1.text = [NSString stringWithFormat:@"%i", number_1];
    num_2.text = [NSString stringWithFormat:@"%i", number_2];
}

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

@end

和ViewController.h

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController
{
    IBOutlet UILabel *num_1;
    IBOutlet UILabel *num_2;
    IBOutlet UILabel *result_label;
    IBOutlet UITextField *textField;

    int number_1;
    int number_2;
    NSString *verify_result;
    NSString *enteredText;
    BOOL display_result;
}

- (IBAction)clickButtonResult:(id)sender;

@end

输入正确的结果后，应该使用updateMyView函数更新UIView，但它没有发生。

任何人都可以帮忙吗？

Answer 1

首先，开始使用Properties。

ViewController.h

@interface ViewController : UIViewController

@property (nonatomic, weak) IBOutlet UILabel *num_1;
@property (nonatomic, weak) IBOutlet UILabel *num_2;
@property (nonatomic, weak) IBOutlet UILabel *resultLabel;
@property (nonatomic, weak) IBOutlet UITextField *textField;

@property (nonatomic) NSInteger number_1;
@property (nonatomic) NSInteger number_2;

@property (nonatomic, strong) NSString *verifyResult;
@property (nonatomic, strong) NSString *enteredText;
@property (nonatomic) BOOL displayResult;

- (IBAction)clickButtonResult:(id)sender;

@end

在ViewController.m代码中，使用self。{name of property}，例如text.Field属性的self.textField。

现在，转到“界面”构建器并将IBOutlet属性连接到正确的对象。（单击文件所有者上的右键）

Answer 2

尝试更改num_1.text中的viewDidLoad，以确保您可以通过UIViewController访问该标签。

所以在viewDidLoad中，只需添加类似

的内容

num1.text = @"Updated from viewDidLoad"

Answer 3

确保您已正确连接num_1和num_2 UILabels。看来你没有连接这些。

Answer 4

将[self updateMyView];移到if函数中的clickButtonResult:语句之外然后它会在点击按钮时更新视图。

if (final_int_result) {
    //result_label.text = @"Correct";
    NSLog(@"Correct");

} else {
    //result_label.text = @"Wrong";
    NSLog(@"Wrong");
}
[self updateMyView];

UIView没有在iPhone App中更新

4 个答案: