我正在为Mail.app制作一个插件。我希望这个插件为Mail的工具栏添加一个按钮。为此,我决定最好的方法是调用函数在MessageViewer的initialize方法中添加此按钮(MessageViewer是Mail.app的FirstResponder的类)。我修改的代码似乎很好地工作:但是不能调整类方法
+ (void) initialize
{
[super initialize];
// class_setSuperclass([self class], NSClassFromString(@"MVMailBundle"));
// [ArchiveMailBundle registerBundle];
// Add a couple methods to the MessageViewer class.
Class MessageViewer = NSClassFromString(@"MessageViewer");
// swizzleSuccess should be NO if any of the following three calls fail
BOOL swizzleSuccess = YES;
swizzleSuccess &= [[self class] copyMethod:@selector(_specialValidateMenuItem:)
fromClass:[self class]
toClass:MessageViewer];
swizzleSuccess &= [[self class] copyMethod:@selector(unsubscribeSelectedMessages:)
fromClass:[self class]
toClass:MessageViewer];
,当我试图做同样的,这是行不通的:
// //Copy the method to the original MessageViewer
swizzleSuccess &= [[self class] copyMethod:@selector(_specialInitMessageViewer:)
fromClass:[self class]
toClass:MessageViewer];
这里是混写方法:
+ (BOOL)swizzleMethod:(SEL)origSel withMethod:(SEL)altSel inClass:(Class)cls
{
// For class (cls), swizzle the original selector with the new selector.
//debug lines to try to figure out why swizzling is failing.
// if (!cls || !origSel) {
// NSLog(@"Something was null. Uh oh.");
//}
Method origMethod = class_getInstanceMethod(cls, origSel);
if (!origMethod) {
NSLog(@"Swizzler -- original method %@ not found for class %@", NSStringFromSelector(origSel),
[cls className]);
return NO;
}
//if (!altSel) NSLog(@"altSel null. :(");
Method altMethod = class_getInstanceMethod(cls, altSel);
if (!altMethod) {
NSLog(@"Swizzler -- alternate method %@ not found for class %@", NSStringFromSelector(altSel),
[cls className]);
return NO;
}
method_exchangeImplementations(origMethod, altMethod);
return YES;
}
+ (BOOL) copyMethod:(SEL)sel fromClass:(Class)fromCls toClass:(Class)toCls
{
// copy a method from one class to another.
Method method = class_getInstanceMethod(fromCls, sel);
if (!method)
{
NSLog(@"copyMethod-- method %@ could not be found in class %@", NSStringFromSelector(sel),
[fromCls className]);
return NO;
}
class_addMethod(toCls, sel,
class_getMethodImplementation(fromCls, sel),
method_getTypeEncoding(method));
return YES;
}
似乎在调用class_getInstanceMethod要失败的,因为我得到的日志中的错误。这发生在我自己的类中的方法以及MessageViewer的初始化方法。
我在这里没有考虑到一些问题吗?
您的代码格式不正确,看起来有点乱。您需要每条代码行至少有4个空格才能使其不被破坏。 – 2010-12-08 02:10:00