用繪製內容在UIView上清除背景顏色

Question

在我的FirstView中，我放置了第二個視圖，我想用它來繪製內容。繪圖工作正常，但問題是第二個視圖的背景是黑色的。我試圖設置視圖的背景色以清除顏色：

[self setBackgroundColor:[UIColor clearColor]]; 

但它仍然是黑色的。

#import "CustomView.h" 

@interface CustomView() 

@end 

@implementation CustomView 


-(void)drawRect:(CGRect)rect 
    { 

     UIBezierPath *aPath = [UIBezierPath bezierPath]; 

     aPath.lineWidth = 15; 

     //set the stoke color 
     [[UIColor greenColor] setStroke]; 

     // Set the starting point of the shape. 
     [aPath moveToPoint:CGPointMake(100.0, 0.0)]; 

     // Draw the lines. 
     [aPath addLineToPoint:CGPointMake(200.0, 40.0)]; 
     [aPath addLineToPoint:CGPointMake(160, 140)]; 
     [aPath addLineToPoint:CGPointMake(40.0, 140)]; 
     [aPath addLineToPoint:CGPointMake(0.0, 40.0)]; 
     [aPath closePath]; 

     //draw the path 
     [aPath stroke]; 
    } 





@end 

Answer 1

你是否將兩個視圖設置爲[UIColor clearColor]？我認爲你需要基於此：iphone: make view transparent but subviews non transparent