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Swift中使用protocol的注意事项,
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OC中protocol是用weak和assign修饰的弱引用.Swift中protocol功能被增强了,如果使用以下代码就会变成强引用.
protocol TestDelegate
{
func cellClicked(let@H_403_5@ index:Int,let@H_403_5@ data:AnyObject);
}
class Test: NSObject,TestDelegate {
var@H_403_5@ b:Test2?;
func cellClicked(let@H_403_5@ index:Int,let@H_403_5@ data:AnyObject)
{
}
static@H_403_5@ func test()
{
var@H_403_5@ a:Test? = Test();
a?.b = Test2();
a?.b?.delegate@H_403_5@ = a;
a = nil;
}
deinit
{
print("test deinit"@H_403_5@);
}
}
class Test2:NSObject {
var@H_403_5@ delegate@H_403_5@:TestDelegate?;
deinit
{
print("Test2 deinit"@H_403_5@);
}
}
上述代码,deinit永远不会被调用,因为Test实例被Test2实例强引用了
protocol TestDelegate:class
{
func cellClicked(let@H_403_5@ index:Int,let@H_403_5@ data:AnyObject)
{
}
static@H_403_5@ func test()
{
var@H_403_5@ a:Test? = Test();
a?.b = Test2();
a?.b?.delegate@H_403_5@ = a;
把protocol修饰成class,delegate对象用weak修饰.
原文链接:https://www.f2er.com/swift/324225.html