安装weex-chart插件 提示iOS项目不是weexpack创建的

[emptywalker]

我使用weex create xxx创建的项目，在使用weex plugin add weex-chart安装插件时，提示以下信息，请问该如何手动添加这个插件

 emptywalker$ weex plugin add weex-chart 
Installing "[email protected]" for ios
Failed to install 'weex-chart':Error
    at new Api (/Users/emptywalker/.xtoolkit/node_modules/weexpack/lib/src/platforms/ios_pack/Api.js:85:15)
    at Object.getPlatformApi (/Users/emptywalker/.xtoolkit/node_modules/weexpack/lib/src/platforms/platforms.js:76:23)
    at handleInstall (/Users/emptywalker/.xtoolkit/node_modules/weexpack/lib/src/plugman/install.js:614:27)
    at /Users/emptywalker/.xtoolkit/node_modules/weexpack/lib/src/plugman/install.js:410:28
    at _fulfilled (/Users/emptywalker/.xtoolkit/node_modules/weexpack/node_modules/q/q.js:787:54)
    at self.promiseDispatch.done (/Users/emptywalker/.xtoolkit/node_modules/weexpack/node_modules/q/q.js:816:30)
    at Promise.promise.promiseDispatch (/Users/emptywalker/.xtoolkit/node_modules/weexpack/node_modules/q/q.js:749:13)
    at /Users/emptywalker/.xtoolkit/node_modules/weexpack/node_modules/q/q.js:509:49
    at flush (/Users/emptywalker/.xtoolkit/node_modules/weexpack/node_modules/q/q.js:108:17)
    at _combinedTickCallback (internal/process/next_tick.js:131:7)
Error: The provided path "~/platforms/ios/Weexplugin" is not a weexpack iOS project.