cocos2d-x android 项目横竖屏切换 jni实现

1.确认AndroidManifest.xml中相应的activity设置了orientation， 如

<activity android:name=\".Hello\"
                  android:label=\"@string/app_name\"
                  android:screenOrientation=\"landscape\"
                  android:theme=\"@android:style/Theme.NoTitleBar.Fullscreen\"
                  android:configChanges=\"orientation\">
            <intent-filter>
                <action android:name=\"android.intent.action.MAIN\" />
                <category android:name=\"android.intent.category.LAUNCHER\" />
            </intent-filter>
        </activity>

2.修改 主activity类的java代码，添加修改屏幕方向的接口：

package com.gaofeng.game;

import org.cocos2dx.lib.Cocos2dxActivity;

import android.content.Intent;
import android.os.Bundle;
import android.util.Log;

public class Hello extends Cocos2dxActivity{

    //added to save activity instance
    static Hello myClass;

    protected void onCreate(Bundle savedInstanceState){
        super.onCreate(savedInstanceState);

        //added to set activity instance
        myClass = this;

    }

    static {
         System.loadLibrary("game");
    }
    
    //interface added to be called by c language, return 1 success, 0 failed
    public static int changeOrientation(int orientation)
    {
        myClass.setRequestedOrientation(orientation);
        if(myClass.getRequestedOrientation() == orientation)
        {
            return 1; 
        }
        return 0;
    }
}

3.修改jni接口的main文件，加入调用java来修改orientation的c接口（如果c调java的地方多，可以考虑另写文件，这里只一个接口，main里有jni.h的包含比较方便）

#include \"AppDelegate.h\"
#include \"platform/android/jni/JniHelper.h\"
#include <jni.h>
#include <android/log.h>

#include \"HelloWorldScene.h\"
#include <cstring>
#include <cstdio>

#define  LOG_TAG \"main\"
#define  LOGD(...) __android_log_print(ANDROID_LOG_DEBUG,LOG_TAG,__VA_ARGS__)

using namespace cocos2d;

extern \"C\"
{

JNIEnv *jniEnv = 0;
JavaVM *jniVm = 0;

 CCSize orientationSize[2] = {{0, 0}, {0, 0}};

jint JNI_OnLoad(JavaVM *vm, void *reserved)
{
    //save vm, not needed
    jniVm = vm;

    JniHelper::setJavaVM(vm);

    return JNI_VERSION_1_4;
}

void Java_org_cocos2dx_lib_Cocos2dxRenderer_nativeInit(JNIEnv* env, jobject thiz, jint w, jint h)
{
    jniEnv = env;

    if (!CCDirector::sharedDirector()->getOpenGLView())
    {
        CCEGLView *view = CCEGLView::sharedOpenGLView();
        view->setFrameSize(w, h);

        //save the orientation values, orientationSize[0] save the landscape value and [1] save portrait here
        //u should adjust codes here according to your project
        do{
            orientationSize[0].width = w;
            orientationSize[0].height = h;
            orientationSize[1].width = h;
            orientationSize[1].height = w;
        }while(0);

        AppDelegate *pAppDelegate = new AppDelegate();
        CCApplication::sharedApplication()->run();
    }
    else
    {
        ccDrawInit();
        ccGLInvalidateStateCache();

        CCShaderCache::sharedShaderCache()->reloadDefaultShaders();
        CCTextureCache::reloadAllTextures();
        CCNotificationCenter::sharedNotificationCenter()->postNotification(EVNET_COME_TO_FOREGROUND, NULL);
        CCDirector::sharedDirector()->setGLDefaultValues();
    }
}

int changeOrientation(int orientation)
{
    if(jniEnv)
    {
        //find main activity class
        jclass cls = jniEnv->FindClass(\"com/gaofeng/game/Hello\");

        jmethodID mid = jniEnv->GetStaticMethodID(cls, \"changeOrientation\", \"(I)I\");
        if(mid > 0)
        {
            if(jniEnv->CallStaticIntMethod(cls, mid, orientation))
            {
                CCEGLView *view = CCEGLView::sharedOpenGLView();
                CCSize sz = view->getFrameSize();

                //reset the framesize, if not, the framesize keep its pre values
                 view->setFrameSize(orientationSize[orientation].width, orientationSize[orientation].height);
                return 1;
            }
        }
    }
    return 0;
}


}

4.需要切换横竖屏的地方调用changeOrientation。
  我使用的例子是helloworld，只有一个场景，因为在游戏启动时调用applicationDidFinishLaunching()创建场景，包括
  了初始化类、设置精灵位置等行为，而重设屏幕方向并不会销毁场景重新创建，所以helloworld切换成竖屏时图片显
  示有问题。但实际需要切换横竖屏的时候往往要和切换场景一起进行，所以不会涉及这个问题。请以实际项目为准
  进行资源适配。