ios - 触摸 move UILabel 一直有效，直到值修复 - 错误还是功能？

Question

一个非常奇怪的结果。

1. 启动单一 View 应用程序
2. 添加一个 UILabel

3. 把我的代码放进去

   导入“ViewController.h”

   @interface ViewController ()
   {
      float oldX, oldY;
   bool dragging;
   __weak IBOutlet UILabel *textLable;
   }
   @end
   
   @implementation ViewController
   
   - (void)viewDidLoad {
      [super viewDidLoad];
      // Do any additional setup after loading the view, typically from a nib.
      // self.textLable.backgroundColor = [UIColor clearColor];
   }
   
   - (void)didReceiveMemoryWarning {
      [super didReceiveMemoryWarning];
      // Dispose of any resources that can be recreated.
   }
   
   - (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
   {
       // get touch event
       UITouch *touch = [[event allTouches] anyObject];
       CGPoint touchLocation = [touch locationInView:self.view];
       if ([touch view] == textLable)
       {
          int intValue =  (int)((touchLocation.y * 24.0)/300.0);
          NSString *anyValue = [NSString stringWithFormat:@"%d",intValue];
   
          textLable.center= touchLocation;
   
          // RUN WITHOUT THIS PART .... tochedMoved workt great
          //
          // Run With this PART ..... touchedMoved is damaged!!!!!
          //textLable.text = anyValue;
          NSLog(@"%f %f", touchLocation.y, textLable.frame.origin.y);
       }
   }
   @end
   

4. 用

   连接标签

   __weak IBOutlet UILabel *textLable;

5. 让它运行

现在您可以通过触摸 move 来 move 标签。

好的...现在!!!!

改变改变

 // RUN WITHOUT THIS PART .... tochedMoved workt great
 //
 // Run With this PART ..... touchedMoved is damaged!!!!!
 //textLable.text = anyValue;

到

 // RUN WITHOUT THIS PART .... tochedMoved workt great
 //
 // Run With this PART ..... touchedMoved is damaged!!!!!
 textLable.text = anyValue; //<------------------------------

运行应用程序并尝试 move !!!如果您开始触摸 move ，您会看到标签在新位置和起始位置之间跳转。

我尝试使用 UIView 作为容器......同样的事情:一旦你改变了 move 对象的值(UIButton 相同)， move 就无法正常工作。

向 Appel 的报告已经发送...没有回答!!!

是 Bug 还是功能？？？

Answer 1

这个想法是关于你的框架和你的位置触摸。您正在将 Label 置于您的触摸中心。所以没有什么是关于设置文本的。试试这段代码，在第一次触摸时检测触摸和中心文本之间的距离，并将中心标签添加到这一点:

    @interface ViewController ()
{
    float distanceTouchX, distanceTouchY;
    bool dragging;
    CGPoint firstLocation;
    __weak IBOutlet UILabel *textLable;
}
@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
}

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
    UITouch *touch = [[event allTouches] anyObject];
    CGPoint touchLocation = [touch locationInView:self.view];

    distanceTouchX = textLable.center.x - touchLocation.x;
    distanceTouchY = textLable.center.y - touchLocation.y;

}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
    // get touch event
    UITouch *touch = [[event allTouches] anyObject];
    CGPoint touchLocation = [touch locationInView:self.view];
    if ([touch view] == textLable)
    {
        int intValue =  (int)((touchLocation.y * 24.0)/320.0);

        NSString *anyValue = [NSString stringWithFormat:@"%d",intValue];

        CGPoint newTouchLocation = touchLocation;
        newTouchLocation.x = newTouchLocation.x + distanceTouchX;
        newTouchLocation.y = newTouchLocation.y + distanceTouchY;

        textLable.center= newTouchLocation;
        textLable.text = anyValue;
        NSLog(@"%f %f", touchLocation.y, textLable.frame.origin.y);
    }
}
@end