无法将void转换为int

Question

I'm making my first Android plug in for unity and I've ran into one issue I can't resolve. Right now, this plug in is extremely simple. All it does it return an increasing number but with the method being create in a native Android file. Then I call this method from inside Unity to see the number rise.

Here is my code. The Android Java file:

package com.test.app;

import com.unity3d.player.UnityPlayerActivity;
import android.content.Context;
import android.os.Bundle;
import android.util.Config;
import android.util.Log;

public class PluginTest extends UnityPlayerActivity
{
    private static final String TAG = "PluginTest_Unity";
    private static int number = 0;

@Override
protected void onCreate(Bundle myBundle)
{
    super.onCreate(myBundle);
}

@Override
protected void onResume()
{
    if(Config.DEBUG)
    {
        Log.d(TAG, "onResume");
    }
    super.onResume();
}

@Override
protected void onPause()
{
    super.onPause();
}

@Override
protected void onStop()
{
    if(Config.DEBUG)
    {
        Log.d(TAG, "onStop");

    }
    super.onStop();
}

public static int getNumber()
{
    number++;
    return number;
}

}

My C# file in Unity:

using UnityEngine;
using System.Collections;

public class NumberExample : MonoBehaviour 
{
    public GUIText number_output_text;
    AndroidJavaClass pluginTutorialActivityJavaClass;

    // Use this for initialization
    void Start () 
    {
        AndroidJNI.AttachCurrentThread();
        pluginTutorialActivityJavaClass = new AndroidJavaClass("com.test.app.PluginTest");
    }

    // Update is called once per frame
    void Update () 
    {
        int number = pluginTutorialActivityJavaClass.CallStatic("getNumber");
        number_output_text.text = "nr: " + number;
    }
}

However, when I try to build my program in Unity it complains that I cannot convert a void to an int with the following line:

int number = pluginTutorialActivityJavaClass.CallStatic("getNumber");

Can anyone see the change I need to make with my code?

Answer 1

From the docs :

To call a static method with a non-void return type, use the generic version.

// Create a java.lang.String object, and call static method valueOf(float value).
function Start() {
    var jo = new AndroidJavaObject("java.lang.String");
    var valueString = jo.CallStatic<string>("valueOf", 42.f);
}

You should probably call

int number = pluginTutorialActivityJavaClass.CallStatic<int>("getNumber");