對象 - 問題畫兩點

Question

之間的直線

我現在的OBJ-C代碼：

- (void)slopeMode:(CGPoint)point{ 
    if (dPoint1.x != -1) //If a coordinate pos has already been set for dPoint1 
    { 
     dPoint2 = point; //Then set it in dPoint2 instead 


     [cPath moveToPoint: CGPointMake(dPoint1.x-5,dPoint1.y-5)]; 
     [cPath addLineToPoint:CGPointMake(dPoint2.x-5,dPoint2.y-5)]; 
     [cPath moveToPoint:CGPointMake(dPoint2.x-5,dPoint2.y-5)]; 

     [cPath addArcWithCenter:CGPointMake(dPoint2.x-5,dPoint2.y-5) radius:10 startAngle:0 endAngle:DEGREES_TO_RADIANS(360) clockwise:YES]; 

     [cPath closePath]; 
     [[UIColor greenColor] setStroke]; 
     [[UIColor greenColor] setFill]; 

     [cPath fill]; 
     [cPath stroke]; 

     gfxP1.path = [cPath CGPath]; 
     gfxP1.fillColor = [[UIColor greenColor] CGColor]; 
     gfxP1.lineWidth = 4.0; 

     [[wBView layer] addSublayer:gfxP1]; 

     rSlope = [self calcSlope:dPoint1 :dPoint2]; 

     [self callAlert:@"Slope Calculation" :[NSString stringWithFormat:@"%.*f",precision,rSlope] :@"OK"]; 

     //Reset datapoints 
     [self resetDPoint:&dPoint1]; 
     [self resetDPoint:&dPoint2]; 

     //Reset gfx 
     //[self resetCALayer:gfxP1]; 
     //[self resetCALayer:gfxP2]; 

     //Reset other vars 
     cSlope = -1; 
     rSlope = -1; 
     tempFStore = @""; 
    } 

    else 
    { 
     dPoint1 = point;   

     cPath = [UIBezierPath bezierPathWithArcCenter:CGPointMake(dPoint1.x-5,dPoint1.y-5) radius:10 startAngle:0 endAngle:DEGREES_TO_RADIANS(360) clockwise:YES];  
    } 
} 

我的問題是，我能到我的UIView對象，但行我想中顯示我的兩個點添加將這兩點連接在一起不會被創建或不能正確顯示。以下是我在IPhone模擬器使用上面的代碼中看到：

Answer 1

下面的代碼嘗試（做修改，按您的要求）：

得到兩個CGPoint並把它傳遞到下面的方法：

- (void)drawLine:(CGPoint)startPoint endPoint:(CGPoint)endPoint{ 

    CGContextRef context = UIGraphicsGetCurrentContext(); 
    CGContextSaveGState(context); 
    CGContextSetStrokeColorWithColor(context, [[UIColor redColor]CGColor]);//adjust color 
    CGContextSetLineWidth(context, 1.0);//adjust line width 
    CGContextMoveToPoint(context, startPoint.x, startPoint.y); 
    CGContextAddLineToPoint(context, endPoint.x, endPoint.y); 
    CGContextStrokePath(context); 
    CGContextRestoreGState(context); 

}