从我这里的问题:Without subclassing a UIView or UIViewController: possible to catch if a subview was added?
我想知道如何将答案中的代码移植到 MonoTouch。它基本上用一个新方法替换了一个方法,然后在没有子类化的情况下调用旧方法。是否有可能让这个指针在 MonoTouch 中工作?
//Makes views announce their change of superviews
Method method = class_getInstanceMethod([UIView class], @selector(willMoveToSuperview:));
IMP originalImp = method_getImplementation(method);
void (^block)(id, UIView*) = ^(id _self, UIView* superview) {
[_self willChangeValueForKey:@"superview"];
originalImp(_self, @selector(willMoveToSuperview:), superview);
[_self didChangeValueForKey:@"superview"];
};
IMP newImp = imp_implementationWithBlock((__bridge void*)block);
method_setImplementation(method, newImp);
最佳答案
这看起来很适合我们提供通用机制来劫持方法。以下是您可以同时使用的纯 C# 代码实现:
[DllImport ("/usr/lib/libobjc.dylib")]
extern static IntPtr class_getInstanceMethod (IntPtr classHandle, IntPtr Selector);
[DllImport ("/usr/lib/libobjc.dylib")]
extern static Func<IntPtr,IntPtr,IntPtr> method_getImplementation (IntPtr method);
[DllImport ("/usr/lib/libobjc.dylib")]
extern static IntPtr imp_implementationWithBlock (ref BlockLiteral block);
[DllImport ("/usr/lib/libobjc.dylib")]
extern static void method_setImplementation (IntPtr method, IntPtr imp);
static Func<IntPtr,IntPtr,IntPtr> original_impl;
void HijackWillMoveToSuperView ()
{
var method = class_getInstanceMethod (new UIView ().ClassHandle, new Selector ("willMoveToSuperview:").Handle);
original_impl = method_getImplementation (method);
var block_value = new BlockLiteral ();
CaptureDelegate d = MyCapture;
block_value.SetupBlock (d, null);
var imp = imp_implementationWithBlock (ref block_value);
method_setImplementation (method, imp);
}
delegate void CaptureDelegate (IntPtr block, IntPtr self, IntPtr uiView);
[MonoPInvokeCallback (typeof (CaptureDelegate))]
static void MyCapture (IntPtr block, IntPtr self, IntPtr uiView)
{
Console.WriteLine ("Moving to: {0}", Runtime.GetNSObject (uiView));
original_impl (self, uiView);
Console.WriteLine ("Added");
}
关于ios - 如何将 "method_getImplementation"和 "method_setImplementation"移植到 MonoTouch?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/14127453/