不兼容的指针类型传递类型为＆＃39; CFMutableDataRef＆＃39;的可保留参数。 CanvasView

Question

我目前正在构建一个绘画应用。我收到一个奇怪的错误，我昨天在代码中没有收到：

Incompatible pointer types passing retainable parameter of type 'CFMutableDataRef' (aka 'struct __CFData *')to a CF function expecting 'CGPathRef' (aka 'const struct CGPath *') type

这些行发生错误：

CGContextAddPath(context, tempLine.linePath);

CGContextAddPath(context, self.currentLine.linePath);

CGPathMoveToPoint(self.currentLine.linePath, NULL, cPoint.x, cPoint.y);

CGPathAddLineToPoint(self.currentLine.linePath, NULL, currentPoint.x, currentPoint.y);

CGPathAddLineToPoint(self.currentLine.linePath, NULL, cPoint.x, cPoint.y);

我已导入，但它似乎无法正常工作。

这是我的代码：

@implementation CanvasView
@synthesize lines, currentLine;

-(id)initWithFrame:(CGRect)frame{
    if ((self = [super initWithFrame:frame])) {
        self.backgroundColor = [UIColor clearColor];
        self.currentLine = [[Line alloc] init];
        self.lines = [NSMutableArray arrayWithCapacity:10];
    }
    return self;
}


- (void)drawRect:(CGRect)rect
{
    CGContextRef context = UIGraphicsGetCurrentContext();
    UIGraphicsBeginImageContext(self.frame.size);

    // draw accumulated lines
    if ([self.lines count] > 0) {
        for (Line *tempLine in self.lines){
            CGContextSetAlpha(context, tempLine.opacity);
            CGContextSetStrokeColorWithColor(context, tempLine.lineColor.CGColor);
            CGContextSetLineWidth(context, tempLine.lineWidth);
            CGContextSetLineCap(context, kCGLineCapRound);
            CGContextSetLineJoin(context, kCGLineJoinRound);
            CGContextAddPath(context, tempLine.linePath);
            CGContextStrokePath(context);

            }
    }

    //draw current line
    CGContextSetAlpha(context, self.currentLine.opacity);


    CGContextSetStrokeColorWithColor(context, self.currentLine.lineColor.CGColor);
    CGContextSetLineWidth(context, self.currentLine.lineWidth);
    CGContextSetLineCap(context, kCGLineCapRound);
    CGContextSetLineJoin(context, kCGLineJoinRound);
    CGContextBeginPath(context);
    CGContextAddPath(context, self.currentLine.linePath);
    CGContextStrokePath(context);


    UIGraphicsEndImageContext();


}

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

    CGPathMoveToPoint(self.currentLine.linePath, NULL, cPoint.x, cPoint.y);

    [self setNeedsDisplay];
}

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
    UITouch *touch = [touches anyObject];   
    CGPoint currentPoint = [touch locationInView:self];

    CGPathAddLineToPoint(self.currentLine.linePath, NULL, currentPoint.x, currentPoint.y);

    [self setNeedsDisplay];
}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {  
    UITouch *touch = [touches anyObject];
    CGPoint cPoint = [touch locationInView:self];
    CGPathAddLineToPoint(self.currentLine.linePath, NULL, cPoint.x, cPoint.y);

    [self setNeedsDisplay];
    [self.lines addObject:self.currentLine];
    Line *nextLine = [[Line alloc] initWithOptions:self.currentLine.lineWidth color:self.currentLine.lineColor opacity:self.currentLine.opacity];
    self.currentLine = nextLine;
    NSLog(@"touch #: %u", [self.lines count]);
}

@end