Question: I've tried every option explained step by step [here](https://stackoverflow.com/questions/6760115/importing-a-github-project-into-eclipse) [and here:](https://stackoverflow.com/questions/29245924/import-java-project-from-github-to-eclipse) [and here](https://stackoverflow.com/questions/8070017/how-to-import-a-git-non-eclipse-java-project-into-eclipse) 

And I can't get it to work.

What I want to do is pick [this project:](https://github.com/Simmetrics/simmetrics) , however it may be done (I've tried both through maven and git), and use its code in eclipse. And what I mean by that, is that I get to the point of seeing the folders in eclipse, but I can't create packages since it's not a java project, and if I mess up the code on the files that appear, it doesn't give me a warning nor in general interacts with said code.

So I guess I'm missing some piece of knowledge and I don't know where else to look for it. **What should I do to use that project in my eclipse, and create my own code that calls and uses the classes and methods from said project?**

Thank you in advance.

Answer: 
Yes, I found the similar issue, it seems to me `react-addons-perf` only work on `react`, for `react native` project, you can use `RCTRenderingPerf` which is a built-in tool in `react native` lib. My react native version is `"react-native": "^0.45.1"`

`import PerfMonitor from 'react-native/Libraries/Performance/RCTRenderingPerf';`

Start measurements

```
PerfMonitor.toggle();
PerfMonitor.start();

```

Stop measurements and print Results

```
PerfMonitor.stop();

```

You do not need to explicitly call print method to print the results, `stop()` already covered that.

You can verify it by running:

```
...
  _setIndex(idx){
    PerfMonitor.toggle();
    PerfMonitor.start();
    this.setState({index:idx})
  }

  componentDidUpdate(){
    PerfMonitor.stop();
  }

  render() {
    return (
      <View style={styles.container}>
        <Text>Welcome to react-native {helloWorld()}</Text>
        <Text>Open up App.js to start working on your app!</Text>
        <Text>Changes you make will automatically reload.</Text>
        <Text>Shake your phone to open the developer menu.</Text>
        <Button title="click me to see profiling in console log" onPress={()=> this._setIndex(2)}/>
      </View>
    );
  }
...

```

Make sure `Remote Debug JS` is on, then you can see the results on chrome console.
Did you try enabling the performance monitor in the dev menu by clicking on Show Perf Monitor? 

[Example](https://imgur.com/a/al87N)