目前，我正在开发一个带有WebView前端的原生Android应用程序.
I have something like:
public class dataObject
{
int a;
String b;
}
在活动中，
I have made an array of dataObject, say dataObject x[5];
Now i want to pass these 5 dataObject to my javascript webView interface as JSON in a callback function.
我在网上浏览了一下，似乎大多数教程都在讨论如何转换fromJson().关于toJson()的内容不多.我找到了一个让我明白dataObject.toJson()是可行的.
But how can I pass all 5 dataObjects?
Here's a comprehensive example on how to use Gson with a list of objects. This should demonstrate exactly how to convert to/from Json, how to reference lists, etc.
Test.java:
import com.google.gson.Gson;
import java.util.List;
import java.util.ArrayList;
import com.google.gson.reflect.TypeToken;
import java.lang.reflect.Type;
public class Test {
public static void main (String[] args) {
// Initialize a list of type DataObject
List<DataObject> objList = new ArrayList<DataObject>();
objList.add(new DataObject(0, "zero"));
objList.add(new DataObject(1, "one"));
objList.add(new DataObject(2, "two"));
// Convert the object to a JSON string
String json = new Gson().toJson(objList);
System.out.println(json);
// Now convert the JSON string back to your java object
Type type = new TypeToken<List<DataObject>>(){}.getType();
List<DataObject> inpList = new Gson().fromJson(json, type);
for (int i=0;i<inpList.size();i++) {
DataObject x = inpList.get(i);
System.out.println(x);
}
}
private static class DataObject {
private int a;
private String b;
public DataObject(int a, String b) {
this.a = a;
this.b = b;
}
public String toString() {
return "a = " +a+ ", b = " +b;
}
}
}
To compile it:
javac -cp "gson-2.1.jar:." Test.java
And finally to run it:
java -cp "gson-2.1.jar:." Test
Note that if you're using Windows, you'll have to switch : with ; in the previous two commands.
After you run it, you should see the following output:
[{"a":0,"b":"zero"},{"a":1,"b":"one"},{"a":2,"b":"two"}]
a = 0, b = zero
a = 1, b = one
a = 2, b = two
Keep in mind that this is only a command line program to demonstrate how it works, but the same principles apply within the Android environment (referencing jar libs, etc.)