Cocos2d-x-3.6 用户交互原理---------如何通过JNI连接Java和C++

发布时间：2020-12-14 16:22:57 所属栏目：百科来源：网络整理

导读：cocos2d-x c++ Java JNI 用户交互这里指的就是用户在手机上的点击，滑动以及晃动手机等行为，从而得到相应的反

cocos2d-x c++ Java JNI

用户交互这里指的就是用户在手机上的点击，滑动以及晃动手机等行为，从而得到相应的反馈。今天学习Cocos2dx，遇到交互问题，所以就写出来和大家分享一下。我这里是以Android连接为例的，因为目前我只会Android相关的开发。好了，不多说，看下面步骤：

第一步：在Android中，交互操作的入口在SurfaceView或是GLSurfaceView中的onTouchEvent时间中。本例代码所在位置org.cocos2dx.lib---->Cocos2dxGLSurfaceView.java

[java] 
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 publicbooleanonTouchEvent(finalMotionEventpMotionEvent){
 //thesedataareusedinACTION_MOVEandACTION_CANCEL
finalintpointerNumber=pMotionEvent.getPointerCount();
 int[]ids=newint[pointerNumber];
float[]xs=float[pointerNumber];
float[]ys=float[pointerNumber];
 
for(inti=0;i<pointerNumber;i++){
 ids[i]=pMotionEvent.getPointerId(i);
 xs[i]=pMotionEvent.getX(i);
 ys[i]=pMotionEvent.getY(i);
 }
switch(pMotionEvent.getAction()&MotionEvent.ACTION_MASK){
caseMotionEvent.ACTION_POINTER_DOWN:
intindexPointerDown=pMotionEvent.getAction()>>MotionEvent.ACTION_POINTER_INDEX_SHIFT;
intidPointerDown=pMotionEvent.getPointerId(indexPointerDown);
floatxPointerDown=pMotionEvent.getX(indexPointerDown);
floatyPointerDown=pMotionEvent.getY(indexPointerDown);
 
this.queueEvent(newRunnable(){
 @Override
voidrun(){
 Cocos2dxGLSurfaceView.this.mCocos2dxRenderer.handleActionDown(idPointerDown,xPointerDown,yPointerDown);
 }
 });
break;
caseMotionEvent.ACTION_DOWN:
//thereareonlyonefingeronthescreen
intidDown=pMotionEvent.getPointerId(0);
floatxDown=xs[0];
floatyDown=ys[0];
this.mCocos2dxRenderer.handleActionDown(idDown,xDown,yDown);
caseMotionEvent.ACTION_MOVE:
newRunnable(){
 @Override
voidrun(){
 Cocos2dxGLSurfaceView.this.mCocos2dxRenderer.handleActionMove(ids,xs,ys);
 });
break;
caseMotionEvent.ACTION_POINTER_UP:
intindexPointUp=pMotionEvent.getAction()>>MotionEvent.ACTION_POINTER_INDEX_SHIFT;
intidPointerUp=pMotionEvent.getPointerId(indexPointUp);
floatxPointerUp=pMotionEvent.getX(indexPointUp);
floatyPointerUp=pMotionEvent.getY(indexPointUp);
this.mCocos2dxRenderer.handleActionUp(idPointerUp,xPointerUp,yPointerUp);
caseMotionEvent.ACTION_UP:
 //thereareonlyonefingeronthescreen
intidUp=pMotionEvent.getPointerId(0);
floatxUp=xs[floatyUp=ys[this.mCocos2dxRenderer.handleActionUp(idUp,xUp,yUp);
caseMotionEvent.ACTION_CANCEL:
this.mCocos2dxRenderer.handleActionCancel(ids,ys);
returntrue;
 }

第二步：Cocos2dxGLSurfaceView.this.mCocos2dxRenderer.handleActionDown(idDown,yDown)等相关语句的方法在org.cocos2dx.lib------>Cocos2dxRender.java，代码如下：

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static

native

void

nativeTouchesBegin(

int

id,

float

x,153); background-color:inherit; font-weight:bold">float

y);

voidnativeTouchesEnd(floaty);
voidnativeTouchesMove(int[]ids,153); background-color:inherit; font-weight:bold">float[]xs,153); background-color:inherit; font-weight:bold">float[]ys);
voidnativeTouchesCancel(float[]ys);
voidhandleActionDown(floaty){
Cocos2dxRenderer.nativeTouchesBegin(id,x,y);
voidhandleActionUp( Cocos2dxRenderer.nativeTouchesEnd(id,153); background-color:inherit; font-weight:bold">voidhandleActionCancel(float[]ys){
Cocos2dxRenderer.nativeTouchesCancel(ids,ys);
voidhandleActionMove( Cocos2dxRenderer.nativeTouchesMove(ids,248); line-height:18px; margin:0px!important; padding:0px 3px 0px 10px!important"> }

第三步： private static native void nativeTouchesBegin(final int id,final float x,final float y)这是本地方法，调用c++内容的语句。而这些内容被打包在Android工程中的libs/armeabi/cocos2dcpp.so文件中。所以我们在使用这些方法时一定要加载这个.so文件。代码位置在org.cocos2dx.lib--->Cocos2dxActivity.java，内容如下：

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void

onLoadNativeLibraries(){

try{
ApplicationInfoai=getPackageManager().getApplicationInfo(getPackageName(),PackageManager.GET_META_DATA);
Bundlebundle=ai.metaData;
StringlibName=bundle.getString("android.app.lib_name");
System.loadLibrary(libName);
}catch(Exceptione){
e.printStackTrace();
}

bundle.getString("android.app.lib_name")文件是找出.so文件。和它相关内容在Android工程中AndroidManifest.xml里，内容如下：

[html] 
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<?xmlversion="1.0"encoding="utf-8"?>

<manifestxmlns:android="http://schemas.android.com/apk/res/android"
package="org.cocos.CocosProject4"
android:versionCode="1"
android:versionName="1.0"
android:installLocation="auto">
uses-sdkandroid:minSdkVersion="9"/>
uses-featureandroid:glEsVersion="0x00020000"/>
applicationandroid:label="@string/app_name"
android:icon="@drawable/icon"
meta-dataandroid:name="android.app.lib_name"
android:value="cocos2dcpp"activityandroid:name="org.cocos2dx.cpp.AppActivity"
android:label="@string/app_name"
android:screenOrientation="landscape"
android:theme="@android:style/Theme.NoTitleBar.Fullscreen"
android:configChanges="orientation"intent-filteractionandroid:name="android.intent.action.MAIN"categoryandroid:name="android.intent.category.LAUNCHER"</>
activityapplicationsupports-screensandroid:anyDensity="true"
android:smallScreens="true"
android:normalScreens="true"
android:largeScreens="true"
android:xlargeScreens="true"uses-permissionandroid:name="android.permission.INTERNET"manifest>

第四步：cocos2dcpp.so文件的生成，因为native 方法都在这里面。它的生成在Android工程中的jni文件里么的Android.mk文件（相关内容参考链接）。native方法所在文件路径cocos2d-x-3.6/cocos/platform/android/jni/TouchesJni.cpp,内容如下：

[cpp] 
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#include"base/CCDirector.h"

#include"base/CCEventKeyboard.h"
#include"base/CCEventDispatcher.h"
#include"platform/android/CCGLViewImpl-android.h"
#include<android/log.h>
#include<jni.h>
usingnamespacecocos2d;
extern"C"{
JNIEXPORTvoidJNICALLJava_org_cocos2dx_lib_Cocos2dxRenderer_nativeTouchesBegin(JNIEnv*env,jobjectthiz,jintid,jfloatx,jfloaty){
intptr_tidlong=id;
cocos2d::Director::getInstance()->getOpenGLView()->handleTouchesBegin(1,&idlong,&x,&y);
JNIEXPORTvoidJNICALLJava_org_cocos2dx_lib_Cocos2dxRenderer_nativeTouchesEnd(JNIEnv*env,jfloaty){
intptr_tidlong=id;
cocos2d::Director::getInstance()->getOpenGLView()->handleTouchesEnd(1,&y);
voidJNICALLJava_org_cocos2dx_lib_Cocos2dxRenderer_nativeTouchesMove(JNIEnv*env,jintArrayids,jfloatArrayxs,jfloatArrayys){
intsize=env->GetArrayLength(ids);
jintid[size];
jfloatx[size];
jfloaty[size];
env->GetIntArrayRegion(ids,size,id);
env->GetFloatArrayRegion(xs,x);
env->GetFloatArrayRegion(ys,y);
intptr_tidlong[size];
for(inti=0;i<size;i++)
idlong[i]=id[i];
cocos2d::Director::getInstance()->getOpenGLView()->handleTouchesMove(size,idlong,153); background-color:inherit; font-weight:bold">voidJNICALLJava_org_cocos2dx_lib_Cocos2dxRenderer_nativeTouchesCancel(JNIEnv*env,jfloatArrayys){
intsize=env->GetArrayLength(ids);
jintid[size];
jfloatx[size];
jfloaty[size];
env->GetIntArrayRegion(ids,id);
env->GetFloatArrayRegion(xs,x);
env->GetFloatArrayRegion(ys,87); background-color:inherit; font-weight:bold">intptr_tidlong[size];
inti=0;i<size;i++)
idlong[i]=id[i];
cocos2d::Director::getInstance()->getOpenGLView()->handleTouchesCancel(size,248); line-height:18px; margin:0px!important; padding:0px 3px 0px 10px!important"> }

第五步：cocos2d::Director::getInstance()->getOpenGLView()->handleTouchesBegin(1,&y)这个方法是如何起作用的呢，文件位置在 cocos2d-x-3.6/cocos/platform/CCGLView.cpp，内如如下：

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GLView::handleTouchesBegin(

int

num,

intptr_t

ids[],87); background-color:inherit; font-weight:bold">float

xs[],87); background-color:inherit; font-weight:bold">float

ys[])

{
intptr_tid=0;
floatx=0.0f;
floaty=0.0f;
intunusedIndex=0;
EventTouchtouchEvent;
inti=0;i<num;++i)
id=ids[i];
x=xs[i];
y=ys[i];
autoiter=g_touchIdReorderMap.find(id);
//itisanewtouch
if(iter==g_touchIdReorderMap.end())
{
unusedIndex=getUnUsedIndex();
//ThetouchesismorethanMAX_TOUCHES?
if(unusedIndex==-1){
CCLOG("ThetouchesismorethanMAX_TOUCHES,unusedIndex=%d",unusedIndex);
continue;
Touch*touch=g_touches[unusedIndex]=new(std::nothrow)Touch();
touch->setTouchInfo(unusedIndex,(x-_viewPortRect.origin.x)/_scaleX,
(y-_viewPortRect.origin.y)/_scaleY);
CCLOGINFO("x=%fy=%f",touch->getLocationInView().x,touch->getLocationInView().y);
g_touchIdReorderMap.insert(std::make_pair(id,unusedIndex));
touchEvent._touches.push_back(touch);
if(touchEvent._touches.size()==0)
CCLOG("touchesBegan:size=0");
return;
touchEvent._eventCode=EventTouch::EventCode::BEGAN;
autodispatcher=Director::getInstance()->getEventDispatcher();
dispatcher->dispatchEvent(&touchEvent);
}

第六步：使用。首先要给_eventDispathcer(在CCNote.cpp文件中)添加listener,示例如下：

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autolistener=EventListenerTouchAllAtOnce::create();

listener->onTouchesBegan=CC_CALLBACK_2(ParticleDemo::onTouchesBegan,this);
listener->onTouchesMoved=CC_CALLBACK_2(ParticleDemo::onTouchesMoved,153); background-color:inherit; font-weight:bold">this);
listener->onTouchesEnded=CC_CALLBACK_2(ParticleDemo::onTouchesEnded,108); list-style:decimal-leading-zero outside; color:inherit; line-height:18px; margin:0px!important; padding:0px 3px 0px 10px!important"> _eventDispatcher->addEventListenerWithSceneGraphPriority(listener,153); background-color:inherit; font-weight:bold">this);

其次就是我们实际操作，使交互产生什么样的变化，代码如下：

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ParticleDemo::onTouchesBegan(

const

std::vector<Touch*>&touches,Event*event)

onTouchesEnded(touches,event);
voidParticleDemo::onTouchesMoved(returnonTouchesEnded(touches,event);
voidParticleDemo::onTouchesEnded( autotouch=touches[0];
autolocation=touch->getLocation();
autopos=Vec2::ZERO;
if(_background)
pos=_background->convertToWorldSpace(Vec2::ZERO);
if(_emitter!=nullptr)
_emitter->setPosition(location-pos);
}

上面代码是ParticleTest中的内容，通过dispathcer将参数最终传递给要变化的_mitter，就是粒子发射器的移动。

（编辑：李大同）

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