如何将TVML/JavaScriptCore与UIKit/Objective-C(Swift)联系起来？

Question

到目前为止,tvOS支持两种制作电视应用程序的方法,TVML和UIKit,并且没有正式提及如何混合使用TVML(基本上是XML)用户界面和应用程序逻辑的本机计数器部分和I/O(如播放,流媒体,iCloud持久性等).

那么,哪个是混合TVML和UIKit在新tvOS应用中的最佳解决方案？

在下面我尝试了一个解决方案,遵循从Apple论坛改编的代码片段以及关于JavaScriptCore到ObjC/Swift绑定的相关问题.这是Swift项目中的一个简单的包装类.

import UIKit
import TVMLKit
@objc protocol MyJSClass : JSExport {
    func getItem(key:String) -> String?
    func setItem(key:String, data:String)
}
class MyClass: NSObject, MyJSClass {
    func getItem(key: String) -> String? {
        return "String value"
    }

    func setItem(key: String, data: String) {
        print("Set key:\(key) value:\(data)")
    }
}

代表必须遵守TVApplicationControllerDelegate:

typealias TVApplicationDelegate = AppDelegate
extension TVApplicationDelegate : TVApplicationControllerDelegate {

    func appController(appController: TVApplicationController, evaluateAppJavaScriptInContext jsContext: JSContext) {
        let myClass: MyClass = MyClass();
        jsContext.setObject(myClass, forKeyedSubscript: "objectwrapper");
    }

    func appController(appController: TVApplicationController, didFailWithError error: NSError) {
        let title = "Error Launching Application"
        let message = error.localizedDescription
        let alertController = UIAlertController(title: title, message: message, preferredStyle:.Alert ) self.appController?.navigationController.presentViewController(alertController, animated: true, completion: { () -> Void in
            })
        }

    func appController(appController: TVApplicationController, didStopWithOptions options: [String : AnyObject]?) {
    }

    func appController(appController: TVApplicationController, didFinishLaunchingWithOptions options: [String : AnyObject]?) {
    }
}

在这一点上,javascript非常简单.看看带有命名参数的方法,您需要更改javascript计数器部分方法名称:

   App.onLaunch = function(options) {
       var text = objectwrapper.getItem()
        // keep an eye here, the method name it changes when you have named parameters, you need camel case for parameters:      
       objectwrapper.setItemData("test", "value")
 }

App. onExit = function() {
        console.log('App finished');
    }

现在,假设你有一个非常复杂的js接口来导出像

@protocol MXMJSProtocol<JSExport>
- (void)boot:(JSValue *)status network:(JSValue*)network user:(JSValue*)c3;
- (NSString*)getVersion;
@end
@interface MXMJSObject : NSObject<MXMJSProtocol>
@end
@implementation MXMJSObject
- (NSString*)getVersion {
  return @"0.0.1";
}

你可以这样做

JSExportAs(boot, 
      - (void)boot:(JSValue *)status network:(JSValue*)network user:(JSValue*)c3 );

在JS Counter部分的这一点,你不会做骆驼案:

objectwrapper.bootNetworkUser(statusChanged,networkChanged,userChanged)

但你要做的是:

objectwrapper.boot(statusChanged,networkChanged,userChanged)

最后,再看一下这个界面:

- (void)boot:(JSValue *)status network:(JSValue*)network user:(JSValue*)c3;

传入的值JSValue*是一种在ObjC/Swift和之间传递完成处理程序的方法JavaScriptCore.在本机代码中,您可以使用参数进行调用:

dispatch_async(dispatch_get_main_queue(), ^{
                                           NSNumber *state  = [NSNumber numberWithInteger:status];
                                           [networkChanged.context[@"setTimeout"]
                                            callWithArguments:@[networkChanged, @0, state]];
                                       });

在我的发现中,我已经看到如果你不在主线程和异步上发送,MainThread将挂起.所以我将调用调用完成处理程序回调的javascript"setTimeout"调用.

所以我在这里使用的方法是:

• 使用JSExportAs采取与命名参数方法车,避免骆驼JavaScript的同行一样callMyParam1Param2Param3
• 使用JSValue作为参数,以摆脱完成处理的.在本机端使用callWithArguments.在JS端使用javascript函数;
• dispatch_async 对于完成处理程序,可能在JavaScript端调用setTimeout 0延迟,以避免UI冻结.

[更新] 我已经更新了这个问题,以便更清楚.我发现一个技术解决方案弥合TVML和UIKit以

• 了解最佳编程模型 JavaScriptCode
• 从有权桥JavaScriptCore来ObjectiveC,反之亦然
• 打电话时有最好的表现JavaScriptCode,从Objective-C

Answer 1

此WWDC视频介绍了如何在JavaScript和Obj-C之间进行通信

以下是我从Swift到JavaScript的沟通方式:

//when pushAlertInJS() is called, pushAlert(title, description) will be called in JavaScript.
func pushAlertInJS(){

    //allows us to access the javascript context
    appController!.evaluateInJavaScriptContext({(evaluation: JSContext) -> Void in

        //get a handle on the "pushAlert" method that you've implemented in JavaScript
        let pushAlert = evaluation.objectForKeyedSubscript("pushAlert")

        //Call your JavaScript method with an array of arguments
        pushAlert.callWithArguments(["Login Failed", "Incorrect Username or Password"])

        }, completion: {(Bool) -> Void in
        //evaluation block finished running
    })
}

以下是我从JavaScript到Swift的通信方式(它需要在Swift中进行一些设置):

//call this method once after setting up your appController.
func createSwiftPrint(){

//allows us to access the javascript context
appController?.evaluateInJavaScriptContext({(evaluation: JSContext) -> Void in

    //this is the block that will be called when javascript calls swiftPrint(str)
    let swiftPrintBlock : @convention(block) (String) -> Void = {
        (str : String) -> Void in

        //prints the string passed in from javascript
        print(str)
    }

    //this creates a function in the javascript context called "swiftPrint". 
    //calling swiftPrint(str) in javascript will call the block we created above.
    evaluation.setObject(unsafeBitCast(swiftPrintBlock, AnyObject.self), forKeyedSubscript: "swiftPrint")
    }, completion: {(Bool) -> Void in
    //evaluation block finished running
})
}

[更新]对于那些想知道javascript方面的"pushAlert"外观的人,我将分享在application.js中实现的示例

var pushAlert = function(title, description){
   var alert = createAlert(title, description);
   alert.addEventListener("select", Presenter.load.bind(Presenter));
   navigationDocument.pushDocument(alert);
}


// This convenience funnction returns an alert template, which can be used to present errors to the user.

var createAlert = function(title, description) {  

   var alertString = `<?xml version="1.0" encoding="UTF-8" ?>
       <document>
         <alertTemplate>
           <title>${title}</title>
           <description>${description}</description>

         </alertTemplate>
       </document>`

   var parser = new DOMParser();

   var alertDoc = parser.parseFromString(alertString, "application/xml");

   return alertDoc
}

Answer 2

你提出了一个几乎可行的想法。显示本机视图后，目前还没有直接的方法将基于 TVML 的视图推送到导航堆栈上。我此时所做的是：

let appDelegate = UIApplication.sharedApplication().delegate as! AppDelegate
appDelegate.appController?.navigationController.popViewControllerAnimated(true)
dispatch_async(dispatch_get_main_queue()) {
    tvmlContext!.evaluateScript("showTVMLView()")
}

...然后在 JavaScript 方面：

function showTVMLView() {setTimeout(function(){_showTVMLView();}, 100);}
function _showTVMLView() {//push the next document onto the stack}

这似乎是将执行从主线程转移到 JSVirtualMachine 线程并避免 UI 锁定的最干净的方法。请注意，我至少必须弹出当前的本机视图控制器，否则它会被发送一个致命的选择器。