小编jms*_*617的帖子

在了解NSInvocations时,似乎我对内存管理的理解存在差距.

这是一个示例项目:

@interface DoNothing : NSObject
@property (nonatomic, strong) NSInvocation *invocation;
@end

@implementation DoNothing
@synthesize invocation = _invocation;

NSString *path = @"/Volumes/Macintosh HD/Users/developer/Desktop/string.txt";

- (id)init
{
    self = [super init];
    if (self) {

        SEL selector = @selector(stringWithContentsOfFile:encoding:error:);
        NSInvocation *i = [NSInvocation invocationWithMethodSignature:[NSString methodSignatureForSelector:selector]];

        Class target = [NSString class];
        [i setTarget:target];
        [i setSelector:@selector(stringWithContentsOfFile:encoding:error:)];

        [i setArgument:&path atIndex:2];

        NSStringEncoding enc = NSASCIIStringEncoding;
        [i setArgument:&enc atIndex:3];

        __autoreleasing NSError *error;
        __autoreleasing NSError **errorPointer = &error;
        [i setArgument:&errorPointer atIndex:4];

        // I understand that I need to …