Question

我将图层添加到我的视图中：

    [self.layer insertSublayer:_gradient above:_another.layer];

然后即使我在超级层上调用 needsDisplay ，它似乎也不会被删除：

        [_gradient removeFromSuperlayer];

如何删除它？

Answer 1

你可以在从superlayer中删除后设置渐变nil。它对我有效。

[gradient removeFromSuperlayer];
 gradient =nil;

Answer 2

我使用了这些，然后检查以确保将其删除：

// assuming there is only 1 gradientLayer this should print 1
print(parentView.layer.sublayers?.count as Any)

parentView.layer.sublayers?.removeAll() // remove everything from the parentView
gradientLayer.removeFromSuperlayer() // just to be safe

// check to see if it's in the parentView or not
if let _ = (parentView.layer.sublayers?.compactMap { $0 as? CAGradientLayer })?.first {

    print("gradientLayer has not been removed")
} else {

    print("yay it's removed")
}

// this should now print nil
print(parentView.layer.sublayers?.count as Any)

如何从它的超级层中删除CAGradientLayer

2 个答案: