来自带有Android和sdl的c ++的Java回调

Question

我正在尝试使用android / SDL c ++代码调用Java方法来弹出或更新Toast。 但我越来越

W/dalvikvm( 4026): Invalid indirect reference 0x41e6b710 in decodeIndirectRef

从Java端（例如从常规调用的Handler）进行更新时，Toast似乎可以工作，并且我的消息字符串将Log（）确定，但是只要setText（）中有任何内容（甚至是“ Hello World”），我崩溃。

我的main.cc（参考https://wiki.libsdl.org/SDL_AndroidGetJNIEnv ）

#include <stdlib.h>
#include <stdio.h>
#include <time.h>

#include "SDL.h"

#include <android/log.h>
#include <jni.h>

#define log(...) __android_log_print(ANDROID_LOG_INFO, "SDL/c", __VA_ARGS__);

void progressMessage(const char *message)
{
    log("0) '%s'", message);
    JNIEnv *jni_env = (JNIEnv*)SDL_AndroidGetJNIEnv();
    log("1) env %08x", (unsigned int)jni_env);
    jobject jni_activity = (jobject)SDL_AndroidGetActivity();
    log("2) act %08x", (unsigned int)jni_activity);

    jclass jni_class(jni_env->GetObjectClass(jni_activity));
    log("3) cls %08x", (unsigned int)jni_class);
    jstring jstr = jni_env->NewStringUTF(message);
    log("4) str %08x", (unsigned int)jstr);
    jmethodID method = jni_env->GetMethodID(jni_class,
    "progressMessage", "(Ljava/lang/String;)V    ");
    log("5) met %08x", (unsigned int)method);

    jni_env->CallVoidMethod(jni_activity, method, jstr);
    log("6) done");
    jni_env->DeleteLocalRef(jni_activity);
    jni_env->DeleteLocalRef(jni_class);
}

int main(int argc, char *argv[])
{
    SDL_Window *window;
    SDL_Renderer *renderer;

    if(SDL_CreateWindowAndRenderer(0, 0, 0, &window, &renderer) < 0)
        exit(2);

    Uint8 done = 0;
    SDL_Event event;

    int loop = 0;
    while(!done)
    {
        if (loop % 100 == 0)
        {
            char message[256];
            sprintf(message, "Log %d", loop);
            progressMessage(message);
        }

        while(SDL_PollEvent(&event))
        {
            if(event.type == SDL_QUIT || event.type == SDL_KEYDOWN || event.type == SDL_FINGERDOWN)
            {
                done = 1;
            }
        }

        int col = loop % 512;
        if (col > 255)
            col = 256-col;
        SDL_SetRenderDrawColor(renderer, col,col,col, 0xFF);
        SDL_RenderClear(renderer);
        SDL_RenderPresent(renderer);
        SDL_Delay(10);

        loop++;
    }

    exit(0);
}

我的课

package com.example.test;

import android.util.Log;
import android.widget.Toast;
import android.os.Bundle;

import org.libsdl.app.SDLActivity; 

public class SDLTest extends SDLActivity {

    public static Toast toast = null;

    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        toast = Toast.makeText(this, "", Toast.LENGTH_SHORT);

        this.progressMessage("Starting");
    }

    public void progressMessage(String message) {
        Log.i("SDL/java", message);
        toast.setText(message);
        toast.setDuration(Toast.LENGTH_SHORT);
        toast.show();
    }
}

这是logcat的输出

I/SDL     ( 4561): SDL_Android_Init()
I/SDL     ( 4561): SDL_Android_Init() finished!
I/SDL/c   ( 4561): 0) 'Log 0'
I/SDL/c   ( 4561): 1) env 76160ec8
I/SDL/c   ( 4561): 2) act 2d900009
I/SDL/c   ( 4561): 3) cls 1dd00011
I/SDL/c   ( 4561): 4) str 1d200015
I/SDL/c   ( 4561): 5) met 6d788688
I/SDL/java( 4561): Log 0
I/SDL/c   ( 4561): 6) done
I/ActivityManager(  594): Displayed com.example.test/.SDLTest: +218ms
V/SDL     ( 4561): onWindowFocusChanged(): true
I/SDL/c   ( 4561): 0) 'Log 100'
I/SDL/c   ( 4561): 1) env 76160ec8
I/SDL/c   ( 4561): 2) act 1de00011
I/SDL/c   ( 4561): 3) cls 2da00009
I/SDL/c   ( 4561): 4) str 1dc00019
I/SDL/c   ( 4561): 5) met 6d788688
I/SDL/java( 4561): Log 100
I/SDL/c   ( 4561): 6) done
I/SDL/c   ( 4561): 0) 'Log 200'
I/SDL/c   ( 4561): 1) env 76160ec8
I/SDL/c   ( 4561): 2) act 41e64a80
W/dalvikvm( 4561): Invalid indirect reference 0x41e64a80 in decodeIndirectRef
I/dalvikvm( 4561): "SDLThread" prio=5 tid=11 RUNNABLE
I/dalvikvm( 4561):   | group="main" sCount=0 dsCount=0 obj=0x41e75fd0 self=0x761607a0
I/dalvikvm( 4561):   | sysTid=4579 nice=0 sched=0/0 cgrp=apps handle=1981156344
I/dalvikvm( 4561):   | state=R schedstat=( 0 0 0 ) utm=3 stm=11 core=1
I/dalvikvm( 4561):   at org.libsdl.app.SDLActivity.nativeInit(Native Method)
I/dalvikvm( 4561):   at org.libsdl.app.SDLMain.run(SDLActivity.java:915)
I/dalvikvm( 4561):   at java.lang.Thread.run(Thread.java:841)
I/dalvikvm( 4561): 
E/dalvikvm( 4561): VM aborting

看来“活动”指针已损坏。

（我也希望可以将环境，活动，类和方法全部缓存起来）

我错过了什么？

Answer 1

这是一个线程问题。

SDL在单独的线程中启动SDLMain（），因此调用那些Java方法是有问题的！

理想的解决方案是在某些非线程模式下运行SDL，如此处所述http://theorangeduck.com/page/issues-sdl-ios-and-android

但是我已经通过在SDLActivity中公开sendCommand解决了我眼前的问题

public boolean sendCommand(int command, Object data)

并实现一个消息系统，可以由

public void progressMessage(String message) {
    toast.setText(message);
    toast.setDuration(Toast.LENGTH_LONG);
    toast.show();
}

public static boolean sendCommand(int command, String string) {
    return SDLActivity.mSingleton.sendCommand(command, string);
}

@Override
protected boolean onUnhandledMessage(int command, Object param) {
    boolean ok = true;
    switch (command) {
    case COMMAND_USER_PROGRESS:
        progressMessage((String)param);
        break;
    default:
        ok = false;
        break;
    }
    return ok;
}