ios版native.js回调函数时出现EXC_BAD_ACCESS

我参考教程5+ App开发Native.js入门指南
按教程添加了.h和.m文件
在使用test()函数 回调时 xcode报错 EXC_BAD_ACCESS(code=1,address=0x8)，求大大解答呀
ps:我测试不传参数时能成功调用回调函数

// 定义协议  
@protocol NjsHelloEvent <NSObject>  
@required  
-(void) onEventInvoked:(NSString*)name;  
@end  
// -------------------------------------------------------------  
// 定义类NjsHello  
@interface NjsHello : NSObject {  
    NSString *_name;  
    id<NjsHelloEvent > _delegate;  
}  
@property (nonatomic,retain) NSString *name;  
@property (nonatomic,retain) id delegate;  
-(void)updateName:(NSString*)newname;  
-(void)setEventObserver:(id<NjsHelloEvent >)delegate;  
-(void)test;  
+(void)testCount;  
@end  

#import "njshello.h"  
// 实现类NjsHello  
@implementation NjsHello  
@synthesize name=_name;  
-(void)updateName:(NSString*)newname{  
    _name = [newname copy];  
}  
-(void)setEventObserver:(id<NjsHelloEvent >)delegate{  
    _delegate = delegate;  
}  
-(void)test{  
    NSLog(@"My name is: %@",_name);  
    [[self delegate]onEventInvoked:_name];//!!!!!!!!!!!!!!!!!!!!!!!!!  EXC_BAD_ACCESS(code=1,address=0x8)  
}  
-(void)dealloc{  
    [_name release];  
    [super dealloc];  
}  
+(void)testCount{  
    NSLog( @"Static test count" );  
}  
@end

// 导入测试类NjsHello  
var NjsHello = plus.ios.importClass("NjsHello");  
// 实现协议“NjsHelloEvent”的代理  
var hevent = plus.ios.implements( "NjsHelloEvent", {  
    "onEventInvoked":function( name ){  
        console.log( "Invoked Object’s name: "+name ); // 输出“Invoked Object’s name: Tester”  
    }  
} );  
var hello = new NjsHello()  
// 调用updateName方法  
hello.updateName( "Tester" );  
// 设置监听对象  
hello.setEventObserver( hevent );  
// 调用test方法，触发代理事件  
hello.test(); // 触发上面代理对象定义的匿名函数运行