cocos2dx 点击事件分析（2）

<pre name="code" class="cpp">1、java端 Cocos2dxGLSurfaceView类
@Override
	public boolean onTouchEvent(final MotionEvent pMotionEvent) {
		// these data are used in ACTION_MOVE and ACTION_CANCEL **

		//触摸点的个数,也可以理解为多少个手指点击屏幕
		final int pointerNumber = pMotionEvent.getPointerCount(); 

		final int[] ids = new int[pointerNumber];
		final float[] xs = new float[pointerNumber];
		final float[] ys = new float[pointerNumber];

		for (int i = 0; i < pointerNumber; i++) {
			//每个手指都会分配一个唯一的ID，第一个id为0，依次累加1,2..
			//只要手指没有离开屏幕，那么在移动过程中，这个ID不变，都是唯一的
			//所以我们可以根据这个ID来判断手指，而且每个手指移动，都有响应的
			//x,y坐标，不同手指之间的坐标无关
			ids[i] = pMotionEvent.getPointerId(i); 
			xs[i] = pMotionEvent.getX(i);
			ys[i] = pMotionEvent.getY(i);
		}

		switch (pMotionEvent.getAction() & MotionEvent.ACTION_MASK) {
		        //跟多点触控有关，只有当手指个数大于1个时，才会触发，每增加一个手指
			//就会多执行一次，每多一个手指，都没分配一个唯一的ID（idPointerDown）
			//因为第二个手指也会触发类似于第一个手指的点击动作，所以即使处理
			//单点点击事件，也需要考虑第二个手指的点击动作。
			case MotionEvent.ACTION_POINTER_DOWN:
				final int indexPointerDown = pMotionEvent.getAction() >> MotionEvent.ACTION_POINTER_ID_SHIFT;
				final int idPointerDown = pMotionEvent.getPointerId(indexPointerDown);
				final float xPointerDown = pMotionEvent.getX(indexPointerDown);
				final float yPointerDown = pMotionEvent.getY(indexPointerDown);

				this.queueEvent(new Runnable() {
					@Override
					public void run() {
						Cocos2dxGLSurfaceView.this.mCocos2dxRenderer.handleActionDown(idPointerDown,xPointerDown,yPointerDown);
					}
				});
				break;

			case MotionEvent.ACTION_DOWN:	//单点触控
				// there are only one finger on the screen
				//单点触控，也可以理解为，第一个手指触摸屏幕时会触发这个事件，
				//如果第二个手指点击屏幕，则不会触发这个事件，第二个手指即后面的
				//会触发ACTION_POINTER_DOWN事件
				final int idDown = pMotionEvent.getPointerId(0);
				final float xDown = xs[0];
				final float yDown = ys[0];

				this.queueEvent(new Runnable() {
					@Override
					public void run() {
						Cocos2dxGLSurfaceView.this.mCocos2dxRenderer.handleActionDown(idDown,xDown,yDown);
					}
				});
				break;

			case MotionEvent.ACTION_MOVE:
				//手指在屏幕上移动时，（由于屏幕很灵敏，即使点击也会伴随着触发这个动作）
				//会触发这个事件，handleActionMove函数会把所有手指的移动事件,都传递给C++端
				this.queueEvent(new Runnable() {
					@Override
					public void run() {
						Cocos2dxGLSurfaceView.this.mCocos2dxRenderer.handleActionMove(ids,xs,ys);
					}
				});
				break;

			case MotionEvent.ACTION_POINTER_UP:
				final int indexPointUp = pMotionEvent.getAction() >> MotionEvent.ACTION_POINTER_ID_SHIFT;
				final int idPointerUp = pMotionEvent.getPointerId(indexPointUp);
				final float xPointerUp = pMotionEvent.getX(indexPointUp);
				final float yPointerUp = pMotionEvent.getY(indexPointUp);

				this.queueEvent(new Runnable() {
					@Override
					public void run() {
						Cocos2dxGLSurfaceView.this.mCocos2dxRenderer.handleActionUp(idPointerUp,xPointerUp,yPointerUp);
					}
				});
				break;

			case MotionEvent.ACTION_UP:
				// there are only one finger on the screen
				//第一个手指离开屏幕会触发这个事件，如果有第二个手指，
				//也离开屏幕，则会触发ACTION_POINTER_UP事件
				final int idUp = pMotionEvent.getPointerId(0);
				final float xUp = xs[0];
				final float yUp = ys[0];

				this.queueEvent(new Runnable() {
					@Override
					public void run() {
						Cocos2dxGLSurfaceView.this.mCocos2dxRenderer.handleActionUp(idUp,xUp,yUp);
					}
				});
				break;

			case MotionEvent.ACTION_CANCEL:
				this.queueEvent(new Runnable() {
					@Override
					public void run() {
						Cocos2dxGLSurfaceView.this.mCocos2dxRenderer.handleActionCancel(ids,ys);
					}
				});
				break;
		}

        /*
		if (BuildConfig.DEBUG) {
			Cocos2dxGLSurfaceView.dumpMotionEvent(pMotionEvent);
		}
		*/
		return true;
	}

-->>调用相应的jni方法：
	public void handleActionDown(final int pID,final float pX,final float pY) {
		Cocos2dxRenderer.nativeTouchesBegin(pID,pX,pY);
	}

	public void handleActionUp(final int pID,final float pY) {
		Cocos2dxRenderer.nativeTouchesEnd(pID,pY);
	}

	public void handleActionCancel(final int[] pIDs,final float[] pXs,final float[] pYs) {
		Cocos2dxRenderer.nativeTouchesCancel(pIDs,pXs,pYs);
	}

	public void handleActionMove(final int[] pIDs,final float[] pYs) {
		Cocos2dxRenderer.nativeTouchesMove(pIDs,pYs);
	}

2、C++中：TouchesJni.cpp文件
    JNIEXPORT void JNICALL Java_org_cocos2dx_lib_Cocos2dxRenderer_nativeTouchesBegin(JNIEnv * env,jobject thiz,jint id,jfloat x,jfloat y) {
        cocos2d::CCDirector::sharedDirector()->getOpenGLView()->handleTouchesBegin(1,&id,&x,&y);
    }

    JNIEXPORT void JNICALL Java_org_cocos2dx_lib_Cocos2dxRenderer_nativeTouchesEnd(JNIEnv * env,jfloat y) {
        cocos2d::CCDirector::sharedDirector()->getOpenGLView()->handleTouchesEnd(1,&y);
    }

    JNIEXPORT void JNICALL Java_org_cocos2dx_lib_Cocos2dxRenderer_nativeTouchesMove(JNIEnv * env,jintArray ids,jfloatArray xs,jfloatArray ys) {
        int size = env->GetArrayLength(ids);
        jint id[size];
        jfloat x[size];
        jfloat y[size];

        env->GetIntArrayRegion(ids,size,id);
        env->GetFloatArrayRegion(xs,x);
        env->GetFloatArrayRegion(ys,y);

        cocos2d::CCDirector::sharedDirector()->getOpenGLView()->handleTouchesMove(size,id,x,y);
    }

    JNIEXPORT void JNICALL Java_org_cocos2dx_lib_Cocos2dxRenderer_nativeTouchesCancel(JNIEnv * env,y);

        cocos2d::CCDirector::sharedDirector()->getOpenGLView()->handleTouchesCancel(size,y);
    }

    总结：手指ACTION_POINTER_DOWN和ACTION_DOWN事件一次只会触发一个，不会同时出现。
    看cocos2d::CCDirector::sharedDirector()->getOpenGLView()->handleTouchesBegin(1,&y)
    第一个参数表示num，始终为1.

（编辑：李大同）

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