[IOS]如何通过UIView画三角形

1.创建一个实现CustomView,继承UIView

2.重写drawRect

- (void)drawRect:(CGRect)rect {
    // Drawing code
    CGContextRef context = UIGraphicsGetCurrentContext();
    
    // Draw a triangle
    CGContextBeginPath(context);
    CGContextMoveToPoint   (context, self.bounds.size.width/2, 0);  // top
    CGContextAddLineToPoint(context, 0, self.bounds.size.height);  // right
    CGContextAddLineToPoint(context, self.bounds.size.width,self.bounds.size.height);  // left
    CGContextClosePath(context);
    
    CGContextSetRGBFillColor(context, 1, 1, 1, 1);
    CGContextFillPath(context);
    
}

3.使用

CustomView *customView = [[CustomView alloc] initWithFrame:CGRectMake(mainScreen.size.width/2-50, mainScreen.size.height/2-50, 100, 100)];
    customView.backgroundColor = [UIColor lightGrayColor];
    [self.view addSubview:customView];

 参考：

1.IOS用CGContextRef画各种图形(文字、圆、直线、弧线、矩形、扇形、椭圆、三角形、圆角矩形、贝塞尔曲线、图片)