NDK: 处理用户交互事件

在 android_main（struct android_app* state)函数里面设置输入事件处理函数：
state->onInputEvent = &handleInput;//设置输入事件的处理函数，如触摸响应
static int32_t handleInput(struct android_app* app, AInputEvent* event)
{
//获取消息的类型,消息有两种类型，一种是Motion类型一种是key类型。
int32_t lEventType = AInputEvent_getType(event);
switch(lEventType)
{
case AINPUT_EVENT_TYPE_MOTION:
//motion类型的消息的来源有两种，所以要获取消息的来源
switch(AInputEvent_getSource(event))
{
case AINPUT_SOURCE_TOUCHSCREEN:
//消息来源于触摸屏
break;
case AINPUT_SOURCE_TRACKBALL:
//消息来源于trackball
break;
}
break;
case AINPUT_EVENT_TYPE_KEY：
//消息来源于物理键盘或虚拟键盘，这个处理是一样的
break;
}
//知道来源与那里的时候，在判断具体是什么消息

int32_t id = AMotionEvent_getAction(event);
switch(id)
{
//触摸移动消息
case AMOTION_EVENT_ACTION_MOVE:
pNode->yaw(Ogre::Radian(Ogre::Degree(10.0f)));
break;
//触摸按下消息
case AMOTION_EVENT_ACTION_DOWN:
pNode->yaw(Ogre::Radian(Ogre::Degree(10.0f)));
break;
触摸弹起消息
case AMOTION_EVENT_ACTION_UP:
pNode->yaw(Ogre::Radian(Ogre::Degree(10.0f)));
break;
}
}
还有一些函数是获取坐标点的， 是绝对坐标：AMotionEvent_getX()，以屏幕左上角为原点。
AMotionEvent_getXOffset（event），返回0.0
AMotionEvent_getXPrecision（event)返回1.0

下面这两个函数用于多点触摸
AMotionEvent_getPointerCount(const
AInputEvent* motion_event);但是测试发现按下两个手指也返回1，不知道是不是硬件问题
AMotionEvent_getPointerId(const AInputEvent* motion_event, size_t pointer_index);不知道怎么用
AMotionEvent_getRawX(event,0);//这个返回的是相对于屏幕左上角的坐标，
AMotionEvent_getX(event,0);//和AMotionEvent_getRawX返回值一样
//这两个函数，如果第二个参数改成1之后，返回值总是为0.0
//说明这个pointer_index还是有用的。
终于弄明白这个point_index是什么意思了，这个值表示第几个手指，哈哈。
但是这个AMotionEvent_getPointerCount无论按下几个手指为什么老是返回1呢？
AMotionEvent_getOrientation(event,0);//总是返回0.0,按下两个手指有时有值。
输入设备有哪些：1 物理键盘，2 D-PAD，3 Trackball
输入类型：
////////////////////////////////////////////////////////////////////////////////////////////
enum {
    /**
     * Command from main thread: the AInputQueue has changed.  Upon processing
     * this command, android_app->inputQueue will be updated to the new queue
     * (or NULL).
     */
    APP_CMD_INPUT_CHANGED,
    /**
     * Command from main thread: a new ANativeWindow is ready for use.  Upon
     * receiving this command, android_app->window will contain the new window
     * surface.
     */
    APP_CMD_INIT_WINDOW,
    /**
     * Command from main thread: the existing ANativeWindow needs to be
     * terminated.  Upon receiving this command, android_app->window still
     * contains the existing window; after calling android_app_exec_cmd
     * it will be set to NULL.
     */
    APP_CMD_TERM_WINDOW,
    /**
     * Command from main thread: the current ANativeWindow has been resized.
     * Please redraw with its new size.
     */
    APP_CMD_WINDOW_RESIZED,
    /**
     * Command from main thread: the system needs that the current ANativeWindow
     * be redrawn.  You should redraw the window before handing this to
     * android_app_exec_cmd() in order to avoid transient drawing glitches.
     */
    APP_CMD_WINDOW_REDRAW_NEEDED,
    /**
     * Command from main thread: the content area of the window has changed,
     * such as from the soft input window being shown or hidden.  You can
     * find the new content rect in android_app::contentRect.
     */
    APP_CMD_CONTENT_RECT_CHANGED,
   /**
     * Command from main thread: the app's activity window has gained
     * input focus.
     */
    APP_CMD_GAINED_FOCUS,
    /**
     * Command from main thread: the app's activity window has lost
     * input focus.
     */
    APP_CMD_LOST_FOCUS,
    /**
     * Command from main thread: the current device configuration has changed.
     */
    APP_CMD_CONFIG_CHANGED,
    /**
     * Command from main thread: the system is running low on memory.
     * Try to reduce your memory use.
     */
    APP_CMD_LOW_MEMORY,
    /**
     * Command from main thread: the app's activity has been started.
     */
    APP_CMD_START,
    /**
     * Command from main thread: the app's activity has been resumed.
     */
    APP_CMD_RESUME,
    /**
     * Command from main thread: the app should generate a new saved state
     * for itself, to restore from later if needed.  If you have saved state,
     * allocate it with malloc and place it in android_app.savedState with
     * the size in android_app.savedStateSize.  The will be freed for you
     * later.
     */
    APP_CMD_SAVE_STATE,
    /**
    * Command from main thread: the app's activity has been paused.
     */
    APP_CMD_PAUSE,
    /**
     * Command from main thread: the app's activity has been stopped.
     */
    APP_CMD_STOP,
    /**
     * Command from main thread: the app's activity is being destroyed,
     * and waiting for the app thread to clean up and exit before proceeding.
     */
    APP_CMD_DESTROY,
};