将字符串数组分配给js变量以便在播放中自动完成？

Question

I have a js variable in the index.html file and i want to do an assignment like this:

var names=["${stateNames}"];

where stateNames is a Java List containing state names. How do i do an assignment like the above so that names now has all the state names contained in stateNames ? The variable stateNames is passed to index.html from the play controller.

Is there any way to do the above ??

Answer 1

If you are using the Groovy templates, this is trivial, because you have access to Groovy's collection methods :

var names=[${stateNames.collect{'"'+it+'"'}.join(",")}];

collect transforms your collection, join creates one big String separated by the given String.

Scala version for completeness' sake:

var names = [@(stateNames.map{"\"" + _ + "\""}.mkString(","))];

Answer 2

There are a number of different options that you can uses here.

1. The neatest option, would be to create a JavaExtension that outputted a comma separated list.
2. You could simply iterate over the list and use the array.push() notation to add each value to your names array.
3. You could use the script tag to iterate over your list, and output the values

Option 1, you would need to create a class like below

package ext;

import play.templates.JavaExtensions;
import java.util.*;

public class MyExtensions extends JavaExtensions {

  public static String stringifyList(List list) {
     StringBuffer buff = new StringBuffer();
     for (Object item: list) {
        buff.append("'"+item.toString()+"'"+",");
     }

     return buff.toString();
  }

}

You would then just use this by using the JavaExtension in your view, so

var names=[${list.stringifyList()}];

Options 2 and 3 are detailed below

<script type="text/javascript">

   // option 2
   var names = new Array();
   #{list items:list, as:'item'}
    names.push('${item}');
   #{/list}

   // option 3
   var names2 = [%{ 
    for (String item: list) {
        out.print("'"+item+"'"+",");
    }
   }%]

</script>