繪圖線5

objective-c
ipad
ios5
line

2012-05-08 82 views 0 likes

我嘗試使用此功能繪圖線5

-(IBAction) DrawLine 
{ 
    CGContextRef c = UIGraphicsGetCurrentContext(); 

     CGFloat red[4] = {1.0f, 0.0f, 0.0f, 1.0f}; 
     CGContextSetStrokeColor(c, red); 
     CGContextBeginPath(c); 
     CGContextMoveToPoint(c, 5.0f, 5.0f); 
     CGContextAddLineToPoint(c, 50.0f, 50.0f); 
     CGContextStrokePath(c); 
}

繪製的目標C線，但我發現，c爲空或爲零，爲什麼？什麼是解決方案？

來源

2012-05-08 kartal