Question

我正在开发一个绘图应用程序，它允许用户在它的superView（self.view）子视图的UIView（InsideView）上绘制UIbezier路径。我在InsideView中使用常规绘图代码，如touchesBegan:, touchesMoved:, touchesEnded:，我在viewController类（InsideView的superView）中处理缩放缩放代码handlePinch:(UIPinchGestureRecognizer *)recognizer:。

当我先画画时，我可以在它之后进行缩放变焦，但是当我首先进行缩放变焦时，绘制代码（touchesBegan等）在UIPinchGestureRecognizer被触发后不会被调用，并且它不会在InsideView上绘制任何内容。我究竟做错了什么？提前致谢。

// InsideView中的代码（它是一个UIView子类，是self.view的子视图）

- (id)initWithFrame:(CGRect)frame{              
                 self = [super initWithFrame:frame];
                 if (self) {
                             path = [UIBezierPath bezierPath];
                             [path setLineWidth:7.0];
                             pointsArray = [NSMutableArray array];
                             finish = NO;
                             }
                   return self;   
}   
-(void)drawRect:(CGRect)rect{
                        [[UIColor redColor] setStroke];
                        [path stroke];
}
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{

                    UITouch *touch = [touches anyObject];
                    CGPoint p = [touch locationInView:self];
                    [path moveToPoint:p];
                    [pointsArray addObject:[NSValue valueWithCGPoint:p]];
}
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{

                    UITouch *touch = [touches anyObject];
                    CGPoint p = [touch locationInView:self];
                    [path addLineToPoint:p];
                    [self setNeedsDisplay];
                    [pointsArray addObject:[NSValue valueWithCGPoint:p]];
}
-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event{

                    [path closePath];

                    //Smoothing the path.
                    path.miterLimit=-10;
                    [self setNeedsDisplay];
                    finish = YES;
}

//Code in the viewController (InsideView's superView)
- (void)viewDidLoad {
        [super viewDidLoad];
        InsideView* sV = [InsideView new];
        [sV setFrame:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)];
        [self.view addSubview:sV];

        //Pinch
        UIPinchGestureRecognizer*pinch = [[UIPinchGestureRecognizer alloc]initWithTarget:self action:@selector(handlePinch:)];
        pinch.delegate =self;
        [sV addGestureRecognizer:pinch];
}
- (void)handlePinch:(UIPinchGestureRecognizer *)recognizer{

        if ([recognizer numberOfTouches] < 2)
            return;
        if (recognizer.state == UIGestureRecognizerStateBegan) {
            lastScale = 1.0;
            lastPoint = [recognizer locationInView:self.view];
        }
        // Scale
        CGFloat scale = 1.0 - (lastScale - recognizer.scale);
        [sV.layer setAffineTransform:
         CGAffineTransformScale([sV.layer affineTransform],
                                scale,
                                scale)];
        lastScale = recognizer.scale;
        // Translate
        CGPoint point = [recognizer locationInView:self.view];

        [sV.layer setAffineTransform:
         CGAffineTransformTranslate([sV.layer affineTransform],
                                    point.x - lastPoint.x,
                                    point.y - lastPoint.y)];
        lastPoint = [recognizer locationInView:self.view];
}
-(void)handlePinchWithGestureRecognizer:(UIPinchGestureRecognizer *)pinchGestureRecognizer{
        sV.transform = CGAffineTransformScale(sV.transform, pinchGestureRecognizer.scale, pinchGestureRecognizer.scale);
        pinchGestureRecognizer.scale = 1.0;
}
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer{
        return YES;
}

Answer 1

我开发了一个UIViewController，我一起使用它们没有任何问题，或许解决方案可能是将这个逻辑从UIView移动到UIViewController。所以在viewDidLoad你可以像这样定义捏合识别器

UIPinchGestureRecognizer* pinch = [[UIPinchGestureRecognizer alloc]initWithTarget:self action:@selector(handlePinch:)];
[self.view addGestureRecognizer:pinch];

当然，方法handlePinch:也应与UIViewController一起移至touchesBegan:withEvent:， touchesMoved:withEvent:，touchesEnded:withEvent:方法

这些方法应该改变的是你应该改变

self

到

self.yourSpecificCurrentUIView

为什么touchesbegan：在使用UIPinchGestureRecognizer后永远不会在UIView上调用？

1 个答案: