Cocoa Selector Question

问题

I have a question on how to use a selector with multiple parameters. I need to toggle this:

-(void)openBackupNamed:(NSString *)name

using this:

[backupList addItemWithTitle:file action:@selector(openBackupNamed:) keyEquivalent:@""];

I know that there is the withObject: parameter for these cases, but I can't do this in the addItemWithTitle:action:keyEquivalent: method or am I missing something?

Thanks

回答1:

In your case you will have to create a new NSInvocation object and set it's index 2 parameter to your NSString (The 0- and 1-indexed parameters are reserved).

Example:

// Assuming:
NSString *myString = ...;

/* / */

NSInvocation *invocation = [NSInvocation invocationWithMethodSignature:[self methodSignatureForSelector:@selector(openBackupNamed:)]];
[invocation setSelector:@selector(openBackupNamed:)];
[invocation setTarget:self];
[invocation setArgument:&myString atIndex: 2];

[invocation invoke]; // or use invokeWithTarget: instead of the above setTarget method.

Read the ADC NSInvocation Class Reference

Please mind the setArgument message. You have to pass it the address of your parameter (your string), not the actual object itself.

来源：https://stackoverflow.com/questions/3076825/cocoa-selector-question