objective-c - UIView仅设置侧面边框

有没有一种方法可以将UIView的边框的边设置为一种颜色，而将顶部和底部保留为另一种颜色？

最佳答案

不，CALayer边界不支持这种行为。完成所需操作的最简单方法是，在 View 的每一侧添加一个n点宽的不透明 subview ，并将所需的边框颜色作为其背景色。

例:

CGSize mainViewSize = theView.bounds.size;
CGFloat borderWidth = 2;
UIColor *borderColor = [UIColor redColor];
UIView *leftView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, borderWidth, mainViewSize.height)];
UIView *rightView = [[UIView alloc] initWithFrame:CGRectMake(mainViewSize.width - borderWidth, 0, borderWidth, mainViewSize.height)];
leftView.opaque = YES;
rightView.opaque = YES;
leftView.backgroundColor = borderColor;
rightView.backgroundColor = borderColor;

// for bonus points, set the views' autoresizing mask so they'll stay with the edges:
leftView.autoresizingMask = UIViewAutoresizingFlexibleHeight | UIViewAutoresizingFlexibleRightMargin;
rightView.autoresizingMask = UIViewAutoresizingFlexibleHeight | UIViewAutoresizingFlexibleLeftMargin;

[theView addSubview:leftView];
[theView addSubview:rightView];

[leftView release];
[rightView release];

请注意，这与CALayer边界的行为完全不符-左边界 View 和右边界 View 将始终位于其 super View 的边界之内。