如何在移動圖像時保持並拖動圖像？

Question

這是我的隨機移動圖像和觸摸代碼的代碼。

-(void)viewDidAppear:(BOOL)animated { 

timer = [NSTimer scheduledTimerWithTimeInterval:5 target:self selector:@selector(randomizeXandY) userInfo:nil repeats:YES]; 
} 

-(void)randomizeXandY { 

CGFloat x = (CGFloat) (arc4random() % (int) self.view.bounds.size.width); 
CGFloat y = (CGFloat) (arc4random() % (int) self.view.bounds.size.height); 

[self moveObjectsAtX:x Y:y]; 

} 

-(void)moveObjectsAtX:(CGFloat)x Y:(CGFloat)y { 

[UIView animateWithDuration:5 animations:^{ 
    imgView.center = CGPointMake(x, y); 
}]; 

} 

-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event { 

UITouch *touch = [[event allTouches]anyObject]; 
CGPoint touchLocation = [touch locationInView:self.view]; 

    if ([touch view] == imgView) { 

     imgView.center = touchLocation; 
    } 

} 

Answer 1

嘗試在touchesBegin代碼和touchesEnded

-(void)touchesBegin:(NSSet *)touches withEvent:(UIEvent *)event { 

// stop timers here 

} 

-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event { 

// start timers here again 

} 

Answer 2

你必須使用以下方法：

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

    //... 
} 

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event { 

    UITouch *touch = [[event allTouches] anyObject]; 
    CGPoint touchLocation = [touch locationInView:self.view]; 
    //.. 

} 

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

    //... 
} 

中的touchesBegan方法

，檢查觸摸是你的形象：

if (CGRectContainsPoint(yourImage.frame, touchLocation)){ 
    dragging = YES; 
} 

如果是的話設置一個全局變量，例如bool拖動到YES。

在touchesMoved：

檢查

if (dragging){ 
    yourImage.frame = CGRectMake(touchLocation.x, touchLocation.y,yourImage.frame.size.widht,yourImage.frame.size.height); 
} 

在touchesEnded

： 組拖到NO

拖動= NO;

所以：

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

    if (CGRectContainsPoint(yourImage.frame, touchLocation)){ 
     dragging = YES; 
     [timer invalidate]; 
     timer = nil; 
    } 
    //... 
} 

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event { 

    UITouch *touch = [[event allTouches] anyObject]; 
    CGPoint touchLocation = [touch locationInView:self.view]; 

    if (dragging){ 
     yourImage.frame = CGRectMake(touchLocation.x, touchLocation.y,yourImage.frame.size.widht,yourImage.frame.size.height); 
    } 
    //.. 

} 

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

    dragging = NO; 
    //... 
} 

Answer 3

我寧願建議使用UIPanGestureRecognizer。在它的處理方法中，您可以檢查觸摸的可能狀態。

-(void)handlePan:(UIPanGestureRecognizer *)recognizer { 
     switch (recognizer.state) { 
      case UIGestureRecognizerStateBegan: { 
       CGPoint touchLocation = [recognizer locationInView:self.view]; 

       ... 

       break; 
      } 

      case UIGestureRecognizerStateChanged: 

       ... 

       break; 

      case UIGestureRecognizerStateEnded: 

       ... 

       break; 

      default: 
       break; 
}