cocos2dx android平台事件系統解析

對於cocos2dx在android平台事件的響應過程很模糊，於是分析了下源碼，cocos2dx 版本3.4，先導入一個android工程，然后看下AndroidManifest.xml

    <application android:label="@string/app_name"
                 android:icon="@drawable/icon">
                     
        <!-- Tell Cocos2dxActivity the name of our .so -->
        <meta-data android:name="android.app.lib_name"
                  android:value="cocos2dcpp" />

        <activity android:name="org.cocos2dx.cpp.AppActivity"
                  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>
    </application>

由此得知啟動窗口類為 org.cocos2dx.cpp.AppActivity，並繼承之 Cocos2dxActivity

package org.cocos2dx.cpp;

import org.cocos2dx.lib.Cocos2dxActivity;

public class AppActivity extends Cocos2dxActivity {
}

public abstract class Cocos2dxActivity extends Activity implements Cocos2dxHelperListener 

看下 Cocos2dxActivity 的 onCreate

    @Override
    protected void onCreate(final Bundle savedInstanceState) {
        Log.i(TAG, "------onCreate----");
        super.onCreate(savedInstanceState);
        CocosPlayClient.init(this, false);

        onLoadNativeLibraries();//加載了一些靜態庫

        sContext = this;
        this.mHandler = new Cocos2dxHandler(this);
        
        Cocos2dxHelper.init(this);
        
        this.mGLContextAttrs = getGLContextAttrs();
        this.init();//初始化

        if (mVideoHelper == null) {
            mVideoHelper = new Cocos2dxVideoHelper(this, mFrameLayout);
        }
        
        if(mWebViewHelper == null){
            mWebViewHelper = new Cocos2dxWebViewHelper(mFrameLayout);
        }
    }

onCreate 調用了  init()  初始化

   public void init() {
        
        // FrameLayout
        ViewGroup.LayoutParams framelayout_params =
            new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,
                                       ViewGroup.LayoutParams.MATCH_PARENT);
        mFrameLayout = new FrameLayout(this);
        mFrameLayout.setLayoutParams(framelayout_params);

        // Cocos2dxEditText layout
        ViewGroup.LayoutParams edittext_layout_params =
            new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,
                                       ViewGroup.LayoutParams.WRAP_CONTENT);
        Cocos2dxEditText edittext = new Cocos2dxEditText(this);
        edittext.setLayoutParams(edittext_layout_params);

        // ...add to FrameLayout
        mFrameLayout.addView(edittext);

        // Cocos2dxGLSurfaceView
        this.mGLSurfaceView = this.onCreateView();

        // ...add to FrameLayout
        mFrameLayout.addView(this.mGLSurfaceView);

        // Switch to supported OpenGL (ARGB888) mode on emulator
        if (isAndroidEmulator())
           this.mGLSurfaceView.setEGLConfigChooser(8, 8, 8, 8, 16, 0);

        this.mGLSurfaceView.setCocos2dxRenderer(new Cocos2dxRenderer());
        this.mGLSurfaceView.setCocos2dxEditText(edittext);

        // Set framelayout as the content view
        setContentView(mFrameLayout);
    }

最終顯示的視圖為 this.mGLSurfaceView = this.onCreateView();

    public Cocos2dxGLSurfaceView onCreateView() {
        Cocos2dxGLSurfaceView glSurfaceView = new Cocos2dxGLSurfaceView(this);
        //this line is need on some device if we specify an alpha bits
        if(this.mGLContextAttrs[3] > 0) glSurfaceView.getHolder().setFormat(PixelFormat.TRANSLUCENT);

        Cocos2dxEGLConfigChooser chooser = new Cocos2dxEGLConfigChooser(this.mGLContextAttrs);
        glSurfaceView.setEGLConfigChooser(chooser);

        return glSurfaceView;
    }

Cocos2dxGLSurfaceView 就是最終顯示的視圖，事件處理也在這個類中，包括 onResume，onPause，onSizeChanged，onKeyDown，onTouchEvent等 主要看下onTouchEvent事件的處理過程

 @Override
    public boolean onTouchEvent(final MotionEvent pMotionEvent) {
        
        //Log.d(TAG, "------onTouchEvent action=----"+pMotionEvent.getAction());
        
        // these data are used in ACTION_MOVE and ACTION_CANCEL
        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++) {
            ids[i] = pMotionEvent.getPointerId(i);
            xs[i] = pMotionEvent.getX(i);
            ys[i] = pMotionEvent.getY(i);
        }

        switch (pMotionEvent.getAction() & MotionEvent.ACTION_MASK) {
            case MotionEvent.ACTION_POINTER_DOWN:
                final int indexPointerDown = pMotionEvent.getAction() >> MotionEvent.ACTION_POINTER_INDEX_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:
                // there are only one finger on the screen
                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:
                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_INDEX_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
                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, xs, ys);
                    }
                });
                break;
        }

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

 看下 MotionEvent.ACTION_DOWN，調用了Cocos2dxGLSurfaceView.this.mCocos2dxRenderer.handleActionDown

    public void handleActionDown(final int id, final float x, final float y) {
        Log.i("Cocos2dxRenderer","-----handleActionDown--");
        Cocos2dxRenderer.nativeTouchesBegin(id, x, y);
    }

這里的nativeTouchesBegin 是一個jni方法，是現在cocos2d\cocos\platform\android\jni\TouchesJni.cpp里，

private static native void nativeTouchesBegin(final int id, final float x, final float y);

    JNIEXPORT void JNICALL Java_org_cocos2dx_lib_Cocos2dxRenderer_nativeTouchesBegin(JNIEnv * env, jobject thiz, jint id, jfloat x, jfloat y) {
        intptr_t idlong = id;
        log("----Info:nativeTouchesBegin id = %d, x=%f, y=%f",id,x,y);
        cocos2d::Director::getInstance()->getOpenGLView()->handleTouchesBegin(1, &idlong, &x, &y);
    }

最后調用GLView::handleTouchesBegin 通過 EventDispatcher::dispatchEvent進行事件的分發，調用事件響應函數，都是C++里完成的，就不再往下分析了。

能力有限，分析有誤處請指正。