uniapp 调用ios原生 UIImagePickerController 代理方法不走

var pickerVC = plus.ios.newObject("UIImagePickerController");
var navDelegate = plus.ios.implements("UINavigationControllerDelegate");
var pickerDelegate = plus.ios.implements("UIImagePickerControllerDelegate",{
"imagePickerController:didFinishPickingMediaWithInfo:":function(picker,info){
console.log("111");
console.log(info);
}
});

            plus.ios.invoke(pickerVC,"setPickerDelegate",pickerDelegate);  
            plus.ios.invoke(pickerVC,"setNavDelegate",navDelegate);  

            var UIApplicationClass = plus.ios.importClass("UIApplication");    
            var UIAppObj = UIApplicationClass.sharedApplication();    
            var del = plus.ios.invoke(UIAppObj,"delegate");  
            var appWindowObj = plus.ios.invoke(del,"window");    
            var appRootController = plus.ios.invoke(appWindowObj,"rootViewController");    
            plus.ios.invoke(appRootController,"presentViewController:animated:completion:",pickerVC,true,null);